Being based on units of ten, the metric system makes it convenient to convert from one scale to another. This is why the sciences generally use the metric system. Divers, however, tend to use the system their culture uses, so it’s useful to be able to convert from the metric system to the imperial system. Here are some common equivalents that you may find handy.
Length
1 centimetre = 0.3937 inches
1 metre = 3.28 feet
1 kilometre = 0.62 miles
1 inch = 2.54 centimetres
1 foot = 0.3038 metres
1 mile = 1.61 kilometres
Weight
1 gram = 0.035 ounces
1 kilogram = 2.2 pounds
1 metric ton = 2204.6 pounds
1 ounce = 28.3 grams
1 pound = 0.45 kilograms
1 ton = 907.2 kilograms
Volume
1 litre = 0.22 gallons
1 litre = 0.9 quarts
1 quart = 1.1 litres
1 gallon = 4.4 litres
1 gallon = 0.15 cubic feet
1 cubic foot = 28.3 litres
1 cubic foot = 6.4 gallons
Temperature
To convert from Celsius to Fahrenheit:
(C° × 1.8) + 32
To convert from Fahrenheit to Celsius
(F° − 32) × .555
Heat
1 calorie = the amount of heat needed to raise 1 gram of water 1°C
1 BTU (British Thermal Unit) = the amount of heat required to raise 1 pint (1 pound) of water 1°F
1 BTU = 252 calories.
Tuesday, 25 November 2008
Monday, 24 November 2008
The winter scene
Feels like its been ages and a day since I put finger to keyboard, so apologies.
Contrary to common belief the sun isn't always shining above Athens. Three hundred or so days of sunshine, cannot be considered a poor score by any means, especially for those from northern Europe, but Athens does get its fair share of winter every year too.
Come the autumn, the locals slowly withdraw from the beaches and prepare for this very Greek, twice-a-year ritual of replacing their personal wardrobes. In mid October, all the summer gear, T-shirts,. shorts, flip flops etc is put away till next May, and sweaters, coats and scarves are unearthed. On the city front now, although the tables never disappear from the pavements and the squares, people from now on tend to stay indoors and many restaurants, bars and nightclubs closed for the whole summer are now back in business.
For those of you who started diving in the summer, I sincerely hope you won't be packing away your dive gear. The water's warm enough for a 5mm full wetsuit with hood, gloves and booties. Best of all, for most who shore dive, the parking is easy and the sites deserted.
Contrary to common belief the sun isn't always shining above Athens. Three hundred or so days of sunshine, cannot be considered a poor score by any means, especially for those from northern Europe, but Athens does get its fair share of winter every year too.
Come the autumn, the locals slowly withdraw from the beaches and prepare for this very Greek, twice-a-year ritual of replacing their personal wardrobes. In mid October, all the summer gear, T-shirts,. shorts, flip flops etc is put away till next May, and sweaters, coats and scarves are unearthed. On the city front now, although the tables never disappear from the pavements and the squares, people from now on tend to stay indoors and many restaurants, bars and nightclubs closed for the whole summer are now back in business.
For those of you who started diving in the summer, I sincerely hope you won't be packing away your dive gear. The water's warm enough for a 5mm full wetsuit with hood, gloves and booties. Best of all, for most who shore dive, the parking is easy and the sites deserted.
Saturday, 8 November 2008
Cretaquarium Thalassocosmos
The construction of the Cretaquarium Thalassocosmos in Gournes, Iraklion, Crete was made possible through European Economic Area grants.
As recreational scuba diving service providers we can all support its marine research and conservation efforts by arranging visits to the museum. For example: it's easy for service providers in Crete to pre-register their students enrolled in fish identification courses and following the required dives, to award their 'c' cards during their visit to the museum. Students, in turn, can invite friends and family and can enjoy showing them their experience and expertise.
Click on title for more information on Cretaquarium Thalassocosmos.
As recreational scuba diving service providers we can all support its marine research and conservation efforts by arranging visits to the museum. For example: it's easy for service providers in Crete to pre-register their students enrolled in fish identification courses and following the required dives, to award their 'c' cards during their visit to the museum. Students, in turn, can invite friends and family and can enjoy showing them their experience and expertise.
Click on title for more information on Cretaquarium Thalassocosmos.
Wednesday, 1 October 2008
Pearls of wisdom
Scuba diving is NOT like skiing or riding a bike
It is like moon walking because both moon walking and scuba diving require life support equipment and proper training to handle the equipment. It also often involves travelling to exotic destinations in order to better appreciate the sport.
On diving 'medicals'
While there is nothing wrong with seeking opinions of training agencies, dive shops, instructors or fellow divers (either in person or on the internet), there is no substitute for a medical exam/consult with a physician knowledgeable in diving medicine.
On selecting a dive store
The single most important selection criteria in choosing to return to a particular dive shop is "confidence" ... a belief in the shop's staff, education, travel packages, and equipment. No single dive shop can provide the absolute best possible solution for every diver in every mode of diving done in a variety of environments. So, visit as many as possible stores to get a sense of their inventory and areas of expertise. Then, choose the one that best matches your individual needs as your primary diving resource.
On choosing dive gear
With diving gear, there is no such thing as one-size fits all or one piece of gear that is perfect for all divers in all diving situations. When you decide to purchase dive gear, what is most important is your fit and comfort, not anyone else's. So, go to as many dive shops as you can find, try many different options, and then acquire the product that best fits your needs.
On diving equipment
No one can know everything, about dive equipment, diving, or anything else for that matter. Any new-to-you dive gear will have some unknown features, when in doubt, ask (or read the manual, if available). The ability to ask about the unknown is a positive character trait and a hallmark of a good diver.
On equipment service
Every time life support equipment (BCD and/or regulator) is serviced, it should be tested in safe, confined water before it is used for travel or extreme situations.
On being a role model
Students may listen to what we, as instructors, say, but they will do as we do. As scuba instructors, our best method of teaching is by example.
On evaluating students and divers
The only way to evaluate a student or diver is to listen to them, observe their ease and comfort during dive preparation and in-water diving. In other words, an evaluation of diving skills is simply not possible without doing the dive. It is the individual skills of the diver, not the plastic they carry, that determines their individual levels of expertise. We have all heard that you cannot judge a book by its cover. In diving instruction this means that, while certainly a necessity, there is no guarantee that any C-card, decal, patch or sticker can be assumed to be an accurate and reliable measure of the claimed level of knowledge, skill and experience.
My name on a C-card
My signature on a C card means that the recipient is not only certified but also qualified at the level to which he/she has been trained.
It is like moon walking because both moon walking and scuba diving require life support equipment and proper training to handle the equipment. It also often involves travelling to exotic destinations in order to better appreciate the sport.
On diving 'medicals'
While there is nothing wrong with seeking opinions of training agencies, dive shops, instructors or fellow divers (either in person or on the internet), there is no substitute for a medical exam/consult with a physician knowledgeable in diving medicine.
On selecting a dive store
The single most important selection criteria in choosing to return to a particular dive shop is "confidence" ... a belief in the shop's staff, education, travel packages, and equipment. No single dive shop can provide the absolute best possible solution for every diver in every mode of diving done in a variety of environments. So, visit as many as possible stores to get a sense of their inventory and areas of expertise. Then, choose the one that best matches your individual needs as your primary diving resource.
On choosing dive gear
With diving gear, there is no such thing as one-size fits all or one piece of gear that is perfect for all divers in all diving situations. When you decide to purchase dive gear, what is most important is your fit and comfort, not anyone else's. So, go to as many dive shops as you can find, try many different options, and then acquire the product that best fits your needs.
On diving equipment
No one can know everything, about dive equipment, diving, or anything else for that matter. Any new-to-you dive gear will have some unknown features, when in doubt, ask (or read the manual, if available). The ability to ask about the unknown is a positive character trait and a hallmark of a good diver.
On equipment service
Every time life support equipment (BCD and/or regulator) is serviced, it should be tested in safe, confined water before it is used for travel or extreme situations.
On being a role model
Students may listen to what we, as instructors, say, but they will do as we do. As scuba instructors, our best method of teaching is by example.
On evaluating students and divers
The only way to evaluate a student or diver is to listen to them, observe their ease and comfort during dive preparation and in-water diving. In other words, an evaluation of diving skills is simply not possible without doing the dive. It is the individual skills of the diver, not the plastic they carry, that determines their individual levels of expertise. We have all heard that you cannot judge a book by its cover. In diving instruction this means that, while certainly a necessity, there is no guarantee that any C-card, decal, patch or sticker can be assumed to be an accurate and reliable measure of the claimed level of knowledge, skill and experience.
My name on a C-card
My signature on a C card means that the recipient is not only certified but also qualified at the level to which he/she has been trained.
Tuesday, 23 September 2008
EN 144-3
EN 144-3:2003 is now the new standard for "Outlet Connections For Diving Gases Nitrox And Oxygen", though until August 2008 valves may have been supplied either to this or the previous national standard. The standard now applies to the connection between a gas cylinder-valve and a first stage or compressor connection when the tank contains gas with an oxygen content greater than 22%. What it means is that your nitrox cylinder will have a dedicated outlet valve, your nitrox regulator will have a dedicated connection to your cylinder valve, and filling stations will have a dedicated nitrox filling connector.
Brussels decided that some new regulations were needed regarding the transport of gases under pressure. They decided that each gas should have its own individual tank valve fitting, so that the wrong gas could never be put into a particular cylinder.
There was already a DIN fitting for use with air cylinders (DIN being the German standards body), so they decided to stipulate an entirely different fitting for use with air mixes with a higher content of oxygen than normal - nitrox. They came up with the M26 valve thread, with a larger diameter than the now familiar DIN fitting.
The recommendation was not mandatory till August 2008, and a poll of Greek service providers indicated that no-one seemed aware of it.
As instructors and service providers we have a duty of care to our students and clients. Failing in our duty exposes us to both legal action and liability for any harm caused. Our 3rd party liability insurance may, or may not, decline to pay out, partly or fully, in an accident if the breach of duty of care is bad enough.
Brussels decided that some new regulations were needed regarding the transport of gases under pressure. They decided that each gas should have its own individual tank valve fitting, so that the wrong gas could never be put into a particular cylinder.
There was already a DIN fitting for use with air cylinders (DIN being the German standards body), so they decided to stipulate an entirely different fitting for use with air mixes with a higher content of oxygen than normal - nitrox. They came up with the M26 valve thread, with a larger diameter than the now familiar DIN fitting.
The recommendation was not mandatory till August 2008, and a poll of Greek service providers indicated that no-one seemed aware of it.
As instructors and service providers we have a duty of care to our students and clients. Failing in our duty exposes us to both legal action and liability for any harm caused. Our 3rd party liability insurance may, or may not, decline to pay out, partly or fully, in an accident if the breach of duty of care is bad enough.
Thursday, 18 September 2008
I've given up using Chemical Lights on night dives
For the following reasons:
- Single use
- Limited life
- Can be accidentally activated
- Need to be properly disposed of following a night dive
Now replaced with 'YO ZURI' Japanese fishing LED lights that:
- Are reusable
- Only activate upon contact with water
- Offer 1000 (one thousand) operating hours
- Stop flashing once contacts dry
- Offer a (brighter) flashing light in a choice of Blue, Green & Red colours
These LED's can be purchased from most retailers selling fishing tackle. I suggest you opt for the larger three and a half inch long LED offering one thousand operating hours, rather than its smaller (seven hundred operating hours) counterpart.
- Single use
- Limited life
- Can be accidentally activated
- Need to be properly disposed of following a night dive
Now replaced with 'YO ZURI' Japanese fishing LED lights that:
- Are reusable
- Only activate upon contact with water
- Offer 1000 (one thousand) operating hours
- Stop flashing once contacts dry
- Offer a (brighter) flashing light in a choice of Blue, Green & Red colours
These LED's can be purchased from most retailers selling fishing tackle. I suggest you opt for the larger three and a half inch long LED offering one thousand operating hours, rather than its smaller (seven hundred operating hours) counterpart.
Saturday, 13 September 2008
On tying knots
In a 'Search & Recovery' class we teach the art of knot tying. For those of you who may experience difficulty mastering the Bowline & Sheet Bend, here are two videos I found on YouTube that clearly and simply demonstrate tying these knots.
Bowline
Sheet Bend
Bowline
Sheet Bend
Wednesday, 3 September 2008
Dive site mapping
The role of a dive leader demands knowledge of dive sites as well as the use of dive site maps when conducting a pre-dive briefing. This knowledge should include layout, distances, depths, entry and exit points as well as any possible currents and hazards. Safety is an important factor but having a map will allow divers to visit the best features of the site by marking where they are and what to look out for.
One of the easiest ways to map a dive site is to use a large slate, tape measure, compass, depth gauge and fixed buoy in order to create an accurate picture of the underwater terrain.
Large slate: If possible use one with pre-printed grid markings.
Tape measure: purchase a 30m reel from your local hardware store.
Compass: use a compass to draw intersecting distance arcs.
Secure buoy: use as a central point from which everything is to be measured.
Using this technique
(1) Start by drawing a quick sketch of the site from memory on a slate - it's a good base from which to add measurements and bearings and will help you set parameters.
(2) Select a central point from which everything on the site will be measured (setting up a buoy will allow you to attach a reel to measure distance)
(3) From the central point swim using a U search pattern as it a good way of covering a large area.
(4) Use kick cycles to measure distances between each feature. Find out how many kick cycles it takes you to fin from one end of a 10 meter line to the other. Use this number to convert kick cycles to meters when moving from one feature to the next, noting distance and depth.
(5) Take a bearing from each feature, again from the central point. Mark these on the rough sketch.
(6) Note features as not-to-be missed areas of the dive as well as of any potential hazards. Note entry points for both boat and shore diving.
(7) If drawing to scale you'll need grid paper, protractors and rulers. This will highlight areas that may need to be surveyed if they don't match up correctly.
(8) Note the depths to the bottom if known (make a note after every 5 meters or so) - this helps create contour lines on your final version.
(9) Add relevant topside features (car park, evacuation area, as well as where oxygen and first aid kit is positioned).
One of the easiest ways to map a dive site is to use a large slate, tape measure, compass, depth gauge and fixed buoy in order to create an accurate picture of the underwater terrain.
Large slate: If possible use one with pre-printed grid markings.
Tape measure: purchase a 30m reel from your local hardware store.
Compass: use a compass to draw intersecting distance arcs.
Secure buoy: use as a central point from which everything is to be measured.
Using this technique
(1) Start by drawing a quick sketch of the site from memory on a slate - it's a good base from which to add measurements and bearings and will help you set parameters.
(2) Select a central point from which everything on the site will be measured (setting up a buoy will allow you to attach a reel to measure distance)
(3) From the central point swim using a U search pattern as it a good way of covering a large area.
(4) Use kick cycles to measure distances between each feature. Find out how many kick cycles it takes you to fin from one end of a 10 meter line to the other. Use this number to convert kick cycles to meters when moving from one feature to the next, noting distance and depth.
(5) Take a bearing from each feature, again from the central point. Mark these on the rough sketch.
(6) Note features as not-to-be missed areas of the dive as well as of any potential hazards. Note entry points for both boat and shore diving.
(7) If drawing to scale you'll need grid paper, protractors and rulers. This will highlight areas that may need to be surveyed if they don't match up correctly.
(8) Note the depths to the bottom if known (make a note after every 5 meters or so) - this helps create contour lines on your final version.
(9) Add relevant topside features (car park, evacuation area, as well as where oxygen and first aid kit is positioned).
Tuesday, 2 September 2008
Cylinder cleaning
A recent query from a colleague regarding cylinder cleaning prompted me to list this article on 'Cylinder cleaning and tumbling' by Dr.Dick Boyd, Greg Kent and Dave Anderson of Global Mfg.Corp.
Click on the title to peruse article.
Click on the title to peruse article.
Diving Tourism
Out of the approximately 3,2 million active European divers, an estimated 825,000 tend to travel to their diving destination whilst on holiday each year.
During an average ten day stay, the divers expenditure from dive travel can usually mount up to approximately 3,800 million Euros.
Source:World Recreational Scuba Training Council
During an average ten day stay, the divers expenditure from dive travel can usually mount up to approximately 3,800 million Euros.
Source:World Recreational Scuba Training Council
Monday, 25 August 2008
Entry level course price comparisons worldwide
From an article that appeared in the Wall Street Journal on 12 March, 2008.
Click on title for link to website.
Ever noticed the effect of perceived value on student's performance and engagement in classes? Those who feel like they have made a significant investment in the class are usually more attentive, interested, and likely to continue beyond the entry level class.
Click on title for link to website.
Ever noticed the effect of perceived value on student's performance and engagement in classes? Those who feel like they have made a significant investment in the class are usually more attentive, interested, and likely to continue beyond the entry level class.
Sunday, 24 August 2008
European Standards for Recreational Diving
European Standards for Recreational Diving were published in early 2004 and define the state of the art for scuba diver and instructor training and the operation of dive centres and resorts.
The standards were jointly developed over a five year period by diver training organisations, consumer representatives and government bodies under the auspices of the European Committee for Standardisation, also known as CEN. The objectives of these European Standards (also known as European Norms) are as follows:
For divers:
• to ensure a high level of quality and safety
• to create internationally recognised diver qualifications, so making it simple for divers to have their qualifications recognised internationally
For diving professionals:
• to provide defensible standards for the teaching and guiding of divers
• to provide scuba instructors with an internationally accepted qualification that will allow them to work easily across Europe
For dive centres and resorts:
• To specify safety-related guidelines indicating how the typical activities of a service provider should be conducted; including training, equipment hire, and the conduct of dive trips
Since the introduction of the standards, a need arose to have an independent, respected body audit training organisations that wished to claim compliance with the standards and confirm that they do in fact meet all of the relevant requirements.
As a result the EUF Certification Body was formed, a joint-venture of the European Underwater Federation (EUF) and the Austrian Standards Institute. The EUF Certification Body meets the requirements for certification bodies specified in the European Standard EN 45011.
Certification by the EUF Certification Body follows a stringent auditing process that allows successful training organisations to prove convincingly that their training programmes are in full conformity with the requirements defined in the European Standards on recreational diving services.
European Standard Level & Reference Number
Diver Level 1 Supervised Diver : EN 14153-1
Diver Level 2 Autonomous Diver : EN 14153-2
Diver Level 3 Dive Leader : EN 14153-3
Instructor Level 1 : EN 14413-1
Instructor Level 2 : EN 14413-2
The standards were jointly developed over a five year period by diver training organisations, consumer representatives and government bodies under the auspices of the European Committee for Standardisation, also known as CEN. The objectives of these European Standards (also known as European Norms) are as follows:
For divers:
• to ensure a high level of quality and safety
• to create internationally recognised diver qualifications, so making it simple for divers to have their qualifications recognised internationally
For diving professionals:
• to provide defensible standards for the teaching and guiding of divers
• to provide scuba instructors with an internationally accepted qualification that will allow them to work easily across Europe
For dive centres and resorts:
• To specify safety-related guidelines indicating how the typical activities of a service provider should be conducted; including training, equipment hire, and the conduct of dive trips
Since the introduction of the standards, a need arose to have an independent, respected body audit training organisations that wished to claim compliance with the standards and confirm that they do in fact meet all of the relevant requirements.
As a result the EUF Certification Body was formed, a joint-venture of the European Underwater Federation (EUF) and the Austrian Standards Institute. The EUF Certification Body meets the requirements for certification bodies specified in the European Standard EN 45011.
Certification by the EUF Certification Body follows a stringent auditing process that allows successful training organisations to prove convincingly that their training programmes are in full conformity with the requirements defined in the European Standards on recreational diving services.
European Standard Level & Reference Number
Diver Level 1 Supervised Diver : EN 14153-1
Diver Level 2 Autonomous Diver : EN 14153-2
Diver Level 3 Dive Leader : EN 14153-3
Instructor Level 1 : EN 14413-1
Instructor Level 2 : EN 14413-2
Wednesday, 20 August 2008
A Diver's Guide To Oxygen Therapy Apparatus
This is an electronic reprint and expansion of an article that appeared in Sources (Part 1: July/Aug. 1989, 30-35 & Part 2: Sept/Aug 1989, 72-74). This material is copyrighted and all rights retained by the author. This article is made available as a service to the diving community by the author and may be distributed for any non-commercial or Not-For-Profit use.
About The Author: Larry "Harris" Taylor, Ph.D. is a biochemist and Dive Safety Coordinator at the University of Michigan. He has authored more than 100 scuba related articles. His personal dive library is considered one of the best recreational sources of information in North America.
Copyright 2001-2004 by Larry "Harris" Taylor
All rights reserved.
Every diver has been told that recompression is the treatment of choice for a serious diving malady. However, since divers may dive in locations separated in time and space from recompression facilities, there is often an appreciable delay (12-40 hours, or more) between the onset of the first recognizable symptoms and admission to a recompression facility. Therefore, it is important for divers to accept the reality that they, on the dive site, as the first responders, determine the subsequent quality of life (if life continues) long before professional medical people see the victim. Divers must realize that in the field, without professional medical care, the administration of 100 % oxygen is the treatment of choice for dealing with most serious diving maladies.
Oxygen is often used in traumatic injuries to treat shock-associated hypoxia (lack of oxygen in the body tissues due to a decrease in blood circulation) or to supplement the breathing of those with chronic lung disease. The vast majority of oxygen equipment available to the public is designed to manage those particular problems. These devices have saved lives, and they will continue to do so, in situations that they were designed to manage. However, devices that were designed for home treatments are inadequate for the dive accident scenario. In diving problems, the key to successful management of the diving accident victim pending hyperbaric oxygen therapy is continued breathing of the highest possible concentration of oxygen en route to professional medical assistance.
A serious dive malady can be described as "bubble trouble." A large bubble(s) of gas, composed primarily of nitrogen, an inert gas, has formed and that bubble(s) interferes with normal body functioning. (Note: In decompression sickness a nitrogen bubble forms as the supersaturated nitrogen gas comes out of solution; in an air embolism the bubble initially is air (79 % nitrogen). However, the body’s metabolism uses the oxygen in the air bubble, so that eventually the bubble becomes almost all nitrogen. In decompression sickness, the bubble can form in almost any tissue. In a lung over pressurization event, the bubble of air is injected into the spaces around the lung or directly into arterial circulation. If the bubble enters the arterial circulation, the bubble generally first lodges in a capillary. Since blood flow is only one way, cells downstream from the bubble stop receiving nutrients and oxygen, while cell-toxic metabolic waste products begin to build-up. The result is that cells downstream from the bubble begin to die. Many cells (particularly those of the central nervous system), once dead, are never regenerated. If too many cells die, life is either impaired, or in the worst case, ceases.
Treatment for "bubble trouble" is to reduce the size of the bubble so that the bubble can no longer interfere with normal function or to move the bubble through the capillary and thus restore blood flow. This can be accomplished physically in a recompression chamber. The effect of increased pressure (typically, 165 fsw in air embolism cases and 60 fsw in decompression sickness) is to decrease the volume of the offending bubble. Decreasing bubble size can also be accomplished by the administration of a very high concentration of oxygen.
We use oxygen primarily not to treat trauma-associated hypoxia, but rather as a technique to denitrogenate" the body. Ideally, we wish to initially surround the offending nitrogen bubbles(s) with a pure oxygen environment. Since we begin with a bubble composed almost exclusively of nitrogen, if we surround the bubble with 100% oxygen, then nitrogen in the bubble will move out of the bubble into the nitrogen-poor surroundings. (Remember Daltons law of partial pressure and that all gases wish to remain uniform in concentration through the volume they occupy). The movement of nitrogen out of the bubble is controlled primarily by partial pressure differences. The greater the difference of partial pressure between the outside and inside of the bubble, the faster this movement of gas will occur. Movement of gas will continue until the partial pressure for the gas is the same inside as it is outside the bubble for all gas components within the bubble. If the bubble's surroundings can be kept at a high oxygen concentration, eventually the bubble will have little nitrogen present. Oxygen (having a higher concentration outside the bubble) will move into the bubble. However, The loss of nitrogen (moves out because of partial pressure gradient between inside and outside the bubble) and the consumption of oxygen by cellular processes cause the bubble to shrink in size. Ultimately, the bubble shrinks enough to restore normal function or, if in a capillary, move through the capillary and thus restore blood flow. In order for this process to work, the oxygen concentration administered to the diving accident victim must be exceptionally high, as close to 100% as possible. In other words, to be effective in reducing the bubble (thus, saving body functions or life itself), our oxygen administration equipment should be capable of delivering 100% oxygen while meeting 100% of the patient's respiratory requirements. (See Why 100% for a more detailed discussion.)
There is an enormous diversity of devices on the market for home utilization of oxygen. These devices vary in the amount and percentage of oxygen that can be effectively administered. Remember, the primary concern in the field management of a diving problem is the ability to deliver 100% oxygen to the patient. Let's examine the equipment available today.
CYLINDERS:
Cylinders are available in either aluminum or steel in a variety of sizes. Cylinders should be rated by D.O.T. for oxygen service and painted green. Merely painting a scuba tank green is not a good practice; Cylinders and all equipment rated for oxygen service undergo a special cleaning to insure that no grease or oily combustible material is present in the system. The cylinder should be equipped with a medical oxygen valve, which has two holes that mate to two pins on the oxygen regulator. These valves are commonly opened with a special wrench, although more expensive units will have a convenient handle. Some valves have a cylinder pressure gauge built-in, thus allowing the cylinder pressure to be monitored without having to put on the regulator. For divers, the minimum size should be a 412 liter (14.6 cu. ft.) steel D cylinder. The comparable aluminum cylinder is 415 liters. This will provide 30 to 40 minutes of 100% oxygen delivered by demand valve. It will also provide about 27 minutes of lower concentration oxygen when delivered to a constant flow device at a minimum flow rate of 15 Liters/minute (L/min). The standard kit now contains an aluminum Jumbo D (636.8 Liters; 22.4 cu. ft.) cylinder. This provides about 50 minutes of use by demand system and approximately 42 minutes of use at 15 Liters per minute. Also available is a larger E cylinder that has a volume of 680 liters (24.1 cu. ft.). Larger cylinders (3000 L) are available, but these cylinders are not very portable. Cylinders should be filled only with medical (U.S.P.) grade oxygen. Some people have filled oxygen bottles used in rescue training with compressed air because it is cheaper. Not only is this practice illegal, but also it could be dangerous, as compressed air is 79 % nitrogen. In an emergency, someone could get confused and administer compressed air (21 % oxygen) to a patient who desperately needs 100 % oxygen.
REGULATORS:
The preferred system is a demand mask system. These systems deliver oxygen only when the patient breathes (demands a gas supply) and thus, the patient most efficiently uses the gas in the cylinder. This efficiency, coupled with its ability to furnish nearly 100 % oxygen to the patient is why the demand system is the most desirable oxygen administration system available for use by divers in treating a serious "bubble trouble" event. A demand regulator (analogous to a scuba second stage) requires a high-pressure regulator (analogous to a scuba first stage). There are several of these devices available. The "first" and "second" stages can be purchased separately or combined as part of a demand valve system. Divers can consult their local hospital supply vendor for descriptions and specifics of available units. (In dealing with local vendors, the key word to remember is "demand"; some very good resuscitators on the market do not have the demand feature.) In addition, DAN has assisted in making available to divers a complete oxygen administration kit that includes a demand regulator system. Information on this system is available from DAN
The demand system is very similar to a scuba regulator. When the patient inhales, the second stage senses the decrease in pressure and initiates rapid gas flow. Since this system is sealed from the environment, this mask can deliver approximately 100 % oxygen to the patient. The demand mask system is the current preferred method of oxygen administration to a breathing patient for the management of a serious diving malady.
VARIABLE RATE/ CONSTANT FLOW SYSTEMS:
If a demand system is not used (they are expensive), then the next best option would be an adjustable-flow medical oxygen regulator capable of delivering at least 15 L/min. These regulators deliver a constant flow of oxygen at a rate that can be adjusted by the first responder. Additionally, many demand systems have a first stage that will only furnish gas to a second stage demand regulator. In this case, a separate regulator capable of delivering a minimum of 15 L/min will be needed for the pocket mask to cope with a non-breathing victim. Ideally, a regulator (like that contained within the DAN kit) should be purchased which will supply both a demand valve mask and a constant flow system. Most of the oxygen delivery systems discussed below will be utilized at minimum of 15 L/min, but you want a regulator able to deliver more than the minimum. Most regulators have two gauges: a cylinder pressure gauge and an oxygen flow meter. Simply turning a knob can vary the gas flow. Those regulators used with a cylinder whose valve contains a cylinder pressure gauge may only have a flow meter. Although these systems can, with the proper mask, deliver a reasonable concentration of oxygen, the continuous flow wastes much of the gas supply and is not nearly as effective or efficient as the demand valve in meeting the respiratory requirements of the diving accident victim.
All regulators should be rated for oxygen service and used only on oxygen cylinders. They should be inspected and serviced annually by a qualified technician.
FIXED RATE / CONSTANT FLOW SYSTEMS:
These units typically have a small (often disposable) gas bottles, an on-off valve, and a constant flow delivery of only 6 L/min. These devices often come with only a simple facemask. These units are not capable of delivering the desired high concentrations of oxygen needed to "denitrogenate" and as such, divers should consider them inadequate for their needs in dealing with any diving malady. Although these devices are the least expensive oxygen administration tools available, they are also the least desirable in terms of effectiveness in dealing with a diving "bubble trouble" emergency.
ADAPTORS:
There are commercial and homemade devices available for utilizing scuba regulators with medical oxygen cylinders. This defeats the primary purpose of safety standards that have historically been promulgated to prevent accidents. Many industrial or medical gases are chemically reactive. In addition, there are an abundance of different gases used in medicine. Having standards, which allow regulators to be used on cylinders of only one type of gas, prevents formation of dangerous chemical combinations arising from the mixing of these different gases. It also guarantees that the gas delivery system is chemically compatible with the gas being delivered. Finally, this set of standards insures that the gas being delivered is what you think it should be.
Oxygen is chemically reactive and can interact with a great many compounds. These oxidation reactions liberate heat, enough to initiate combustion or, in some cases, explosions. To prevent accidental chemical reactions from occurring, all oxygen equipment must be rigorously cleaned and degreased. Most scuba diving regulators are not kept scrupulously clean; thus, using a scuba regulator as an oxygen delivery device poses an element of fire risk. There has been at least one reported incident of a fire that occurred because of the use of a scuba regulator and a homemade adaptor on an oxygen cylinder.
There is always a group of divers looking for a way to "beat the system." In the Great Lakes we have divers diving well beyond sport diving depths. Many of these divers are "experimenting with their spinal cords" by using homemade oxygen decompression procedures in the water. Some of these divers are unaware of the risks of breathing 100% oxygen at depth. Although this population is, admittedly, small, an adaptor does provide a potential for abuse by those few people who wish to use oxygen for their in-water decompression procedures. In-water use of oxygen should remain outside the realm of traditional sport diving.
Some of these oxygen-to-scuba adaptors have proven of tremendous value in remote parts of the world. Most North Americans are not that isolated and can have ready access to proper equipment. Lastly, if you already have an oxygen cylinder, a suitable medical oxygen regulator and a demand valve are not much more in cost than the most often used adaptor.
DELIVERY MASKS:
The delivery systems discussed below may supply higher concentrations of oxygen in a clinical setting when used by clinical professionals, but, in the field, in an emergency use by the lay community, it is reasonable to believe the concentrations of oxygen delivered will be significantly less than text-book quoted values.
CONSTANT FLOW DELIVERY DEVICES: The mask used will determine the final concentration of constant flow oxygen that the patient breathes. The gas coming out of the cylinder is 100 % oxygen; the concentration of oxygen the patient actually breathes will depend on how much the oxygen is diluted with air or the patient's exhalation. The final concentration of oxygen delivered will be affected by the actual flow rate, the quality of the seal of the mask around the patient's mouth and nose, and the patient's rate and depth of breathing. In general, the higher the flow rate, the higher the concentration of oxygen the patient will breathe (and the shorter the time that the gas supply will last). The poorer the mask-patient seal, the lower the concentration of oxygen that the patient will receive. In the field, the flow rate and the quality of the mask seal are probably the most important elements in determining the actual concentration of oxygen delivered to the patient. Note that the concentrations of oxygen mask delivery systems listed below are practical values obtained by skilled medical personnel in a clinical setting. Values obtained in the field from highly stressed first responders will probably be lower.
NASAL CANNULA: This device delivers an unpredictable amount of oxygen ranging from 24-32 % at 1 - 6 L/min depending on how much the patient inhales through the mouth. Higher flow rates are uncomfortable for the patient. A high flow rate can quickly dry out the nasal mucosa and become rapidly uncomfortable.
SIMPLE FACEMASK: This device is probably the most commonly available to the public. It seals poorly and its large ventilation holes allow the oxygen flow to be diluted with air. The simple facemask at an oxygen flow of 6 L/min delivers approximately 35-40 % oxygen. Increasing the flow to 10 L/min may increase oxygen concentration to about 50 %. If the flow rate is less than 6 L/min (as cylinder nears empty), the patient may re-breathe much of his own exhalation and thus, the concentration of oxygen delivered will be low, possibly severely hypoxic.
VENTURI MASKS: This device utilizes a mechanical venturi effect to increase oxygen flow rate into the mask; this limits the dilution of the oxygen by air entering into the mask. There are different types of venturi masks available. Typically, these units deliver 24 - 28 % oxygen at 4 L/min and 35 - 40 % oxygen at 8 L/min. This mask should only be used in a clinical setting and should not be used in the field.
PARTIAL REBREATHER: This mask adds a reservoir bag to the simple facemask. This mask appears similar to a non-rebreather mask. However, it is missing a one-way valve between the reservoir bag and the mask. The reservoir bag fills with oxygen. When the patient breathes, much of the inhalation volume comes from the bag and thus, the oxygen concentration delivered is increased. However, with this system the patient's exhalation can mix with gas in the bag. At 6 L/min this system delivers 40-50 % oxygen; at 10-15L/min the partial rebreather can deliver approximately 60 % oxygen. These masks are often called medium concentration oxygen delivery masks.
NON-REBREATHER: This mask consists of a mask that has a reservoir bag attached. The bag is separated from the mask by a one-way valve that prevents air and patient exhalation from diluting the oxygen in the reservoir bag. When the patient inhales, the valve opens and the patient breathes primarily oxygen. There are also one-way valves that cover the holes on the mask to allow patient exhalation to escape without allowing large quantities of air to enter
the mask. Some masks have this one-way valve on both sides of the mask. These masks are prescription only. If both sides are covered and gas flow ceases, then the patient will not be able to breathe because the valves keep air from entering during inhalation. The common high oxygen concentration mask has a one -way valve on only one side so that if gas flow ceases, the patient can still breathe. At a minimum oxygen flow of 15 L/min, as long as the reservoir bag is kept filled and a good seal is maintained, this mask can deliver 60 - 75% oxygen to the patient
The systems described above are designed for use with a patient that is breathing. This accounts for roughly 90 - 95 % of all diving accidents. Since these devices require an inhalation effort from the patient to move the oxygen into the lungs, they will be ineffective in dealing with a non-breathing patient who is in probably the most desperate need of high concentrations of oxygen. The following devices are used for the non-breathing patient.
POCKET MASK: This device is the current suggested means of ventilating a non-breathing scuba diving accident victim. The oxygen line is hooked into a nipple on the mask, gas flow is started, and the rescuer performs mouth-to-pocket mask resuscitation. At 6 L/min the oxygen delivered will be about 35 %. At 15L/min this procedure, with a good mask seal, will deliver about 50 % oxygen to the patient. These units are used in conjunction with a small one-way valve assembly that diverts the patient's exhalation away from the rescuer. The valve also contains a filter to minimize risk of disease transmission between rescuer and patient. The valve assembly should be considered single-use.
SINGLE-USE POCKET MASKS: This disposable device is designed for use in C.P.R. The unit (InterTech # 008010, or equivalent) comes with a single use pocket mask that forms a good seal, a one-way valve to isolate the patient's breath from the rescuer, a short piece of respiratory tubing, and a mouthpiece to make breathing into the device a little easier and more comfortable. By adding a T-adaptor oxygen inlet (Airlife U/Adapit # 004081, or equivalent) and changing the length of respiratory tubing to longer than 12 " (the tubing acts as an oxygen reservoir; the longer the tubing, the higher the final concentration of oxygen that can be delivered), this new device can furnish more than 60 % oxygen to the patient at 15 L/min. Consult your local hospital supply vendor for parts and check your assembly with someone knowledgeable in oxygen administration to insure that the device is properly assembled.
MECHANICAL VENTILATOR: Many demand oxygen systems, as well as special mechanical resuscitators, can utilize oxygen pressure to force oxygen into the lungs. Some of these, particularly older models, do not have overpressure release valves. If too much gas is forced into the lungs, it is possible for the patient to suffer lung damage from the resuscitation effort. All mechanical ventilators require specialized training and therefore belong to the realm of the licensed medical professional. Sport divers, without special training should not utilize these devices. Remember, a primary concern of a first responder is to do no additional harm.
BAG VALVE MASK: This device stores oxygen in a bag that fills from an oxygen reservoir. The oxygen is delivered to the patient by squeezing the large bag. Properly used (which requires three or four hands and/or a lot of properly-supervised practice), this device can furnish nearly 100 % oxygen to the non-breathing patient. To be effective, they must be used in conjunction with an endotracheal airway and should not be used by rescuers who have not had proper training and practice to obtain this necessary skill. (Placement of an oral airway is most definitely a technique that requires training and clinical ability. Improper placement can injure or block the patient's airway. Those without clinical training and proficiency should not attempt Insertion of airway management devices.)
NASAL CANNULA ON RESCUER: One technique for administration of oxygen to an unconscious diver has the rescuer breathing oxygen delivered by a nasal cannula. After breathing oxygen, the rescuer then performs mouth-to-mouth resuscitation on the victim. Note that this technique certainly delivers a greater concentration of oxygen to the victim than mere mouth-to-mouth breathing. Since the nasal cannula can deliver at best about 32% oxygen to the rescuer, the actual oxygen concentration delivered to the patient will be probably between 20 - 30%. The effectiveness of this technique has not yet been demonstrated.
RECOMMENDATIONS FOR A DIVING ACCIDENT MANAGEMENT OXYGEN KIT:
1. Avoid all 6 L/min constant flow devices.
2. The DAN oxygen unit was assembled based on the advice of the hyperbaric medical experts at DAN It contains a single 415 L cylinder (41 minutes supply at 10 L/min. (DAN kits now primarily use an aluminum Jumbo D (636.8 Liters; approximately 50 minutes of gas supply for a demand inhalator)), a demand valve delivery oxygen system for breathing patients and a pocket mask for non-breathing patients. This kit represents the current state of the art for dealing with oxygen administration in a serious diving emergency. As such, the DAN kit (or its equivalent) represents the minimal amount of oxygen equipment that should be present on dive training sites. Dive training should NOT, in my opinion, occur with anything less than this equipment on site. Since many divers dive or train in remote locations and are more than 30 minutes from medical assistance, a second (or more) 415 L (or larger) cylinder is desirable. Divers should have enough gas supply on hand to treat an injured diver for the amount of time it takes for the local site professional emergency response team to travel to the dive site.
INSTRUCTORS PLEASE NOTE: In the US, the DAN oxygen kit is considered the standard-of-care in the diving community for treatment of diving accidents. To train with less than this is a liability risk that you should be unwilling to assume!
3. A reasonable emergency alternative to the demand system, would be one (or more) D or E cylinder, a variable flow (15 L/min) medical oxygen regulator, a high concentration (non-rebreathing) oxygen delivery mask for breathing patients, and either the Laerdal or single-use modification pocket mask described above for a non-breathing patient. I tell my students to carry a non-rebreather mask in their traveling first aid kit. So, if they are in a situation where the only oxygen supply is constant flow and a simple facemask, substitution of the non-rebreather mask for the simple facemask can immediately boost the oxygen concentration given to the patient.
4. For those who already have oxygen cylinders and possibly some oxygen administration equipment, possible additions include:
a. A demand valve and mask with appropriate first stage. Consult your local hospital supply vendor or DAN for advice. Many of these devices contain a lever or trigger for positive pressure mechanical ventilation. If your demand system has a trigger, do not use this trigger unless you have received training in its use. Improper use (especially with older mechanical ventilators) could damage patient's lungs and lead to increased patient injury or death.
b. For those who already have an oxygen regulator capable of delivering 15 L/min and cannot afford a demand mask, a non-rebreathing mask (Hudson # 1059, or equivalent) is a necessary alternative. This mask properly used, will deliver about 60 - 70 % oxygen at 15 L/min. The mask sells for between $ 3 - 6. But remember, for denitrogenation we need the highest possible concentration of oxygen, so, although this system is better than nothing, all efforts should be made to supply accident management kit with a demand system.
c. One of the pocket mask assemblies described above.
d. A rugged carrying case to protect the oxygen unit from rough handling and the environment. Cases with O-rings to insure watertight integrity are recommended for use in marine environments.
Local hospital supply vendors or DAN can be exceptionally helpful to you when you assemble the oxygen administration portion of your emergency response kit. Make certain that you discuss your needs with a respiratory therapist, not just a salesperson. Explain that your oxygen use will be emergency field management of a scuba diving injury, and that your desire is to furnish the highest possible concentration of oxygen with only a limited supply of gas to a scuba diving accident victim. They may also inform you about any local legal restrictions on oxygen equipment or utilization. Note that oxygen used in aircraft, in very small cylinders (like those sold by mail-order), or by rescue personnel for emergency use only are exempt from prescription requirements. (Many local vendors, however, will be more comfortable if you obtain a prescription for your oxygen unit. My personal prescription states that the oxygen unit is only for emergency applications in a diving accident.) Regardless of what you decide to carry in your emergency response kit, remember that people save lives; equipment merely helps. (In an emergency, divers should utilize whatever is available to the best of their abilities within the limitations of their training and the tools assembled.) All the above equipment is useless; unless you (and your buddy) know how to use the life saving tools you will carry with you to the dive site. Thus, you should seek out the training of a knowledgeable dive rescue or oxygen administration instructor who can teach you the proper use of oxygen administration devices. Oxygen administration is a skill that can be easily learned, under proper supervision. Practice now could prevent a later problem from becoming a catastrophe.
About The Author: Larry "Harris" Taylor, Ph.D. is a biochemist and Dive Safety Coordinator at the University of Michigan. He has authored more than 100 scuba related articles. His personal dive library is considered one of the best recreational sources of information in North America.
Copyright 2001-2004 by Larry "Harris" Taylor
All rights reserved.
Every diver has been told that recompression is the treatment of choice for a serious diving malady. However, since divers may dive in locations separated in time and space from recompression facilities, there is often an appreciable delay (12-40 hours, or more) between the onset of the first recognizable symptoms and admission to a recompression facility. Therefore, it is important for divers to accept the reality that they, on the dive site, as the first responders, determine the subsequent quality of life (if life continues) long before professional medical people see the victim. Divers must realize that in the field, without professional medical care, the administration of 100 % oxygen is the treatment of choice for dealing with most serious diving maladies.
Oxygen is often used in traumatic injuries to treat shock-associated hypoxia (lack of oxygen in the body tissues due to a decrease in blood circulation) or to supplement the breathing of those with chronic lung disease. The vast majority of oxygen equipment available to the public is designed to manage those particular problems. These devices have saved lives, and they will continue to do so, in situations that they were designed to manage. However, devices that were designed for home treatments are inadequate for the dive accident scenario. In diving problems, the key to successful management of the diving accident victim pending hyperbaric oxygen therapy is continued breathing of the highest possible concentration of oxygen en route to professional medical assistance.
A serious dive malady can be described as "bubble trouble." A large bubble(s) of gas, composed primarily of nitrogen, an inert gas, has formed and that bubble(s) interferes with normal body functioning. (Note: In decompression sickness a nitrogen bubble forms as the supersaturated nitrogen gas comes out of solution; in an air embolism the bubble initially is air (79 % nitrogen). However, the body’s metabolism uses the oxygen in the air bubble, so that eventually the bubble becomes almost all nitrogen. In decompression sickness, the bubble can form in almost any tissue. In a lung over pressurization event, the bubble of air is injected into the spaces around the lung or directly into arterial circulation. If the bubble enters the arterial circulation, the bubble generally first lodges in a capillary. Since blood flow is only one way, cells downstream from the bubble stop receiving nutrients and oxygen, while cell-toxic metabolic waste products begin to build-up. The result is that cells downstream from the bubble begin to die. Many cells (particularly those of the central nervous system), once dead, are never regenerated. If too many cells die, life is either impaired, or in the worst case, ceases.
Treatment for "bubble trouble" is to reduce the size of the bubble so that the bubble can no longer interfere with normal function or to move the bubble through the capillary and thus restore blood flow. This can be accomplished physically in a recompression chamber. The effect of increased pressure (typically, 165 fsw in air embolism cases and 60 fsw in decompression sickness) is to decrease the volume of the offending bubble. Decreasing bubble size can also be accomplished by the administration of a very high concentration of oxygen.
We use oxygen primarily not to treat trauma-associated hypoxia, but rather as a technique to denitrogenate" the body. Ideally, we wish to initially surround the offending nitrogen bubbles(s) with a pure oxygen environment. Since we begin with a bubble composed almost exclusively of nitrogen, if we surround the bubble with 100% oxygen, then nitrogen in the bubble will move out of the bubble into the nitrogen-poor surroundings. (Remember Daltons law of partial pressure and that all gases wish to remain uniform in concentration through the volume they occupy). The movement of nitrogen out of the bubble is controlled primarily by partial pressure differences. The greater the difference of partial pressure between the outside and inside of the bubble, the faster this movement of gas will occur. Movement of gas will continue until the partial pressure for the gas is the same inside as it is outside the bubble for all gas components within the bubble. If the bubble's surroundings can be kept at a high oxygen concentration, eventually the bubble will have little nitrogen present. Oxygen (having a higher concentration outside the bubble) will move into the bubble. However, The loss of nitrogen (moves out because of partial pressure gradient between inside and outside the bubble) and the consumption of oxygen by cellular processes cause the bubble to shrink in size. Ultimately, the bubble shrinks enough to restore normal function or, if in a capillary, move through the capillary and thus restore blood flow. In order for this process to work, the oxygen concentration administered to the diving accident victim must be exceptionally high, as close to 100% as possible. In other words, to be effective in reducing the bubble (thus, saving body functions or life itself), our oxygen administration equipment should be capable of delivering 100% oxygen while meeting 100% of the patient's respiratory requirements. (See Why 100% for a more detailed discussion.)
There is an enormous diversity of devices on the market for home utilization of oxygen. These devices vary in the amount and percentage of oxygen that can be effectively administered. Remember, the primary concern in the field management of a diving problem is the ability to deliver 100% oxygen to the patient. Let's examine the equipment available today.
CYLINDERS:
Cylinders are available in either aluminum or steel in a variety of sizes. Cylinders should be rated by D.O.T. for oxygen service and painted green. Merely painting a scuba tank green is not a good practice; Cylinders and all equipment rated for oxygen service undergo a special cleaning to insure that no grease or oily combustible material is present in the system. The cylinder should be equipped with a medical oxygen valve, which has two holes that mate to two pins on the oxygen regulator. These valves are commonly opened with a special wrench, although more expensive units will have a convenient handle. Some valves have a cylinder pressure gauge built-in, thus allowing the cylinder pressure to be monitored without having to put on the regulator. For divers, the minimum size should be a 412 liter (14.6 cu. ft.) steel D cylinder. The comparable aluminum cylinder is 415 liters. This will provide 30 to 40 minutes of 100% oxygen delivered by demand valve. It will also provide about 27 minutes of lower concentration oxygen when delivered to a constant flow device at a minimum flow rate of 15 Liters/minute (L/min). The standard kit now contains an aluminum Jumbo D (636.8 Liters; 22.4 cu. ft.) cylinder. This provides about 50 minutes of use by demand system and approximately 42 minutes of use at 15 Liters per minute. Also available is a larger E cylinder that has a volume of 680 liters (24.1 cu. ft.). Larger cylinders (3000 L) are available, but these cylinders are not very portable. Cylinders should be filled only with medical (U.S.P.) grade oxygen. Some people have filled oxygen bottles used in rescue training with compressed air because it is cheaper. Not only is this practice illegal, but also it could be dangerous, as compressed air is 79 % nitrogen. In an emergency, someone could get confused and administer compressed air (21 % oxygen) to a patient who desperately needs 100 % oxygen.
REGULATORS:
The preferred system is a demand mask system. These systems deliver oxygen only when the patient breathes (demands a gas supply) and thus, the patient most efficiently uses the gas in the cylinder. This efficiency, coupled with its ability to furnish nearly 100 % oxygen to the patient is why the demand system is the most desirable oxygen administration system available for use by divers in treating a serious "bubble trouble" event. A demand regulator (analogous to a scuba second stage) requires a high-pressure regulator (analogous to a scuba first stage). There are several of these devices available. The "first" and "second" stages can be purchased separately or combined as part of a demand valve system. Divers can consult their local hospital supply vendor for descriptions and specifics of available units. (In dealing with local vendors, the key word to remember is "demand"; some very good resuscitators on the market do not have the demand feature.) In addition, DAN has assisted in making available to divers a complete oxygen administration kit that includes a demand regulator system. Information on this system is available from DAN
The demand system is very similar to a scuba regulator. When the patient inhales, the second stage senses the decrease in pressure and initiates rapid gas flow. Since this system is sealed from the environment, this mask can deliver approximately 100 % oxygen to the patient. The demand mask system is the current preferred method of oxygen administration to a breathing patient for the management of a serious diving malady.
VARIABLE RATE/ CONSTANT FLOW SYSTEMS:
If a demand system is not used (they are expensive), then the next best option would be an adjustable-flow medical oxygen regulator capable of delivering at least 15 L/min. These regulators deliver a constant flow of oxygen at a rate that can be adjusted by the first responder. Additionally, many demand systems have a first stage that will only furnish gas to a second stage demand regulator. In this case, a separate regulator capable of delivering a minimum of 15 L/min will be needed for the pocket mask to cope with a non-breathing victim. Ideally, a regulator (like that contained within the DAN kit) should be purchased which will supply both a demand valve mask and a constant flow system. Most of the oxygen delivery systems discussed below will be utilized at minimum of 15 L/min, but you want a regulator able to deliver more than the minimum. Most regulators have two gauges: a cylinder pressure gauge and an oxygen flow meter. Simply turning a knob can vary the gas flow. Those regulators used with a cylinder whose valve contains a cylinder pressure gauge may only have a flow meter. Although these systems can, with the proper mask, deliver a reasonable concentration of oxygen, the continuous flow wastes much of the gas supply and is not nearly as effective or efficient as the demand valve in meeting the respiratory requirements of the diving accident victim.
All regulators should be rated for oxygen service and used only on oxygen cylinders. They should be inspected and serviced annually by a qualified technician.
FIXED RATE / CONSTANT FLOW SYSTEMS:
These units typically have a small (often disposable) gas bottles, an on-off valve, and a constant flow delivery of only 6 L/min. These devices often come with only a simple facemask. These units are not capable of delivering the desired high concentrations of oxygen needed to "denitrogenate" and as such, divers should consider them inadequate for their needs in dealing with any diving malady. Although these devices are the least expensive oxygen administration tools available, they are also the least desirable in terms of effectiveness in dealing with a diving "bubble trouble" emergency.
ADAPTORS:
There are commercial and homemade devices available for utilizing scuba regulators with medical oxygen cylinders. This defeats the primary purpose of safety standards that have historically been promulgated to prevent accidents. Many industrial or medical gases are chemically reactive. In addition, there are an abundance of different gases used in medicine. Having standards, which allow regulators to be used on cylinders of only one type of gas, prevents formation of dangerous chemical combinations arising from the mixing of these different gases. It also guarantees that the gas delivery system is chemically compatible with the gas being delivered. Finally, this set of standards insures that the gas being delivered is what you think it should be.
Oxygen is chemically reactive and can interact with a great many compounds. These oxidation reactions liberate heat, enough to initiate combustion or, in some cases, explosions. To prevent accidental chemical reactions from occurring, all oxygen equipment must be rigorously cleaned and degreased. Most scuba diving regulators are not kept scrupulously clean; thus, using a scuba regulator as an oxygen delivery device poses an element of fire risk. There has been at least one reported incident of a fire that occurred because of the use of a scuba regulator and a homemade adaptor on an oxygen cylinder.
There is always a group of divers looking for a way to "beat the system." In the Great Lakes we have divers diving well beyond sport diving depths. Many of these divers are "experimenting with their spinal cords" by using homemade oxygen decompression procedures in the water. Some of these divers are unaware of the risks of breathing 100% oxygen at depth. Although this population is, admittedly, small, an adaptor does provide a potential for abuse by those few people who wish to use oxygen for their in-water decompression procedures. In-water use of oxygen should remain outside the realm of traditional sport diving.
Some of these oxygen-to-scuba adaptors have proven of tremendous value in remote parts of the world. Most North Americans are not that isolated and can have ready access to proper equipment. Lastly, if you already have an oxygen cylinder, a suitable medical oxygen regulator and a demand valve are not much more in cost than the most often used adaptor.
DELIVERY MASKS:
The delivery systems discussed below may supply higher concentrations of oxygen in a clinical setting when used by clinical professionals, but, in the field, in an emergency use by the lay community, it is reasonable to believe the concentrations of oxygen delivered will be significantly less than text-book quoted values.
CONSTANT FLOW DELIVERY DEVICES: The mask used will determine the final concentration of constant flow oxygen that the patient breathes. The gas coming out of the cylinder is 100 % oxygen; the concentration of oxygen the patient actually breathes will depend on how much the oxygen is diluted with air or the patient's exhalation. The final concentration of oxygen delivered will be affected by the actual flow rate, the quality of the seal of the mask around the patient's mouth and nose, and the patient's rate and depth of breathing. In general, the higher the flow rate, the higher the concentration of oxygen the patient will breathe (and the shorter the time that the gas supply will last). The poorer the mask-patient seal, the lower the concentration of oxygen that the patient will receive. In the field, the flow rate and the quality of the mask seal are probably the most important elements in determining the actual concentration of oxygen delivered to the patient. Note that the concentrations of oxygen mask delivery systems listed below are practical values obtained by skilled medical personnel in a clinical setting. Values obtained in the field from highly stressed first responders will probably be lower.
NASAL CANNULA: This device delivers an unpredictable amount of oxygen ranging from 24-32 % at 1 - 6 L/min depending on how much the patient inhales through the mouth. Higher flow rates are uncomfortable for the patient. A high flow rate can quickly dry out the nasal mucosa and become rapidly uncomfortable.
SIMPLE FACEMASK: This device is probably the most commonly available to the public. It seals poorly and its large ventilation holes allow the oxygen flow to be diluted with air. The simple facemask at an oxygen flow of 6 L/min delivers approximately 35-40 % oxygen. Increasing the flow to 10 L/min may increase oxygen concentration to about 50 %. If the flow rate is less than 6 L/min (as cylinder nears empty), the patient may re-breathe much of his own exhalation and thus, the concentration of oxygen delivered will be low, possibly severely hypoxic.
VENTURI MASKS: This device utilizes a mechanical venturi effect to increase oxygen flow rate into the mask; this limits the dilution of the oxygen by air entering into the mask. There are different types of venturi masks available. Typically, these units deliver 24 - 28 % oxygen at 4 L/min and 35 - 40 % oxygen at 8 L/min. This mask should only be used in a clinical setting and should not be used in the field.
PARTIAL REBREATHER: This mask adds a reservoir bag to the simple facemask. This mask appears similar to a non-rebreather mask. However, it is missing a one-way valve between the reservoir bag and the mask. The reservoir bag fills with oxygen. When the patient breathes, much of the inhalation volume comes from the bag and thus, the oxygen concentration delivered is increased. However, with this system the patient's exhalation can mix with gas in the bag. At 6 L/min this system delivers 40-50 % oxygen; at 10-15L/min the partial rebreather can deliver approximately 60 % oxygen. These masks are often called medium concentration oxygen delivery masks.
NON-REBREATHER: This mask consists of a mask that has a reservoir bag attached. The bag is separated from the mask by a one-way valve that prevents air and patient exhalation from diluting the oxygen in the reservoir bag. When the patient inhales, the valve opens and the patient breathes primarily oxygen. There are also one-way valves that cover the holes on the mask to allow patient exhalation to escape without allowing large quantities of air to enter
the mask. Some masks have this one-way valve on both sides of the mask. These masks are prescription only. If both sides are covered and gas flow ceases, then the patient will not be able to breathe because the valves keep air from entering during inhalation. The common high oxygen concentration mask has a one -way valve on only one side so that if gas flow ceases, the patient can still breathe. At a minimum oxygen flow of 15 L/min, as long as the reservoir bag is kept filled and a good seal is maintained, this mask can deliver 60 - 75% oxygen to the patient
The systems described above are designed for use with a patient that is breathing. This accounts for roughly 90 - 95 % of all diving accidents. Since these devices require an inhalation effort from the patient to move the oxygen into the lungs, they will be ineffective in dealing with a non-breathing patient who is in probably the most desperate need of high concentrations of oxygen. The following devices are used for the non-breathing patient.
POCKET MASK: This device is the current suggested means of ventilating a non-breathing scuba diving accident victim. The oxygen line is hooked into a nipple on the mask, gas flow is started, and the rescuer performs mouth-to-pocket mask resuscitation. At 6 L/min the oxygen delivered will be about 35 %. At 15L/min this procedure, with a good mask seal, will deliver about 50 % oxygen to the patient. These units are used in conjunction with a small one-way valve assembly that diverts the patient's exhalation away from the rescuer. The valve also contains a filter to minimize risk of disease transmission between rescuer and patient. The valve assembly should be considered single-use.
SINGLE-USE POCKET MASKS: This disposable device is designed for use in C.P.R. The unit (InterTech # 008010, or equivalent) comes with a single use pocket mask that forms a good seal, a one-way valve to isolate the patient's breath from the rescuer, a short piece of respiratory tubing, and a mouthpiece to make breathing into the device a little easier and more comfortable. By adding a T-adaptor oxygen inlet (Airlife U/Adapit # 004081, or equivalent) and changing the length of respiratory tubing to longer than 12 " (the tubing acts as an oxygen reservoir; the longer the tubing, the higher the final concentration of oxygen that can be delivered), this new device can furnish more than 60 % oxygen to the patient at 15 L/min. Consult your local hospital supply vendor for parts and check your assembly with someone knowledgeable in oxygen administration to insure that the device is properly assembled.
MECHANICAL VENTILATOR: Many demand oxygen systems, as well as special mechanical resuscitators, can utilize oxygen pressure to force oxygen into the lungs. Some of these, particularly older models, do not have overpressure release valves. If too much gas is forced into the lungs, it is possible for the patient to suffer lung damage from the resuscitation effort. All mechanical ventilators require specialized training and therefore belong to the realm of the licensed medical professional. Sport divers, without special training should not utilize these devices. Remember, a primary concern of a first responder is to do no additional harm.
BAG VALVE MASK: This device stores oxygen in a bag that fills from an oxygen reservoir. The oxygen is delivered to the patient by squeezing the large bag. Properly used (which requires three or four hands and/or a lot of properly-supervised practice), this device can furnish nearly 100 % oxygen to the non-breathing patient. To be effective, they must be used in conjunction with an endotracheal airway and should not be used by rescuers who have not had proper training and practice to obtain this necessary skill. (Placement of an oral airway is most definitely a technique that requires training and clinical ability. Improper placement can injure or block the patient's airway. Those without clinical training and proficiency should not attempt Insertion of airway management devices.)
NASAL CANNULA ON RESCUER: One technique for administration of oxygen to an unconscious diver has the rescuer breathing oxygen delivered by a nasal cannula. After breathing oxygen, the rescuer then performs mouth-to-mouth resuscitation on the victim. Note that this technique certainly delivers a greater concentration of oxygen to the victim than mere mouth-to-mouth breathing. Since the nasal cannula can deliver at best about 32% oxygen to the rescuer, the actual oxygen concentration delivered to the patient will be probably between 20 - 30%. The effectiveness of this technique has not yet been demonstrated.
RECOMMENDATIONS FOR A DIVING ACCIDENT MANAGEMENT OXYGEN KIT:
1. Avoid all 6 L/min constant flow devices.
2. The DAN oxygen unit was assembled based on the advice of the hyperbaric medical experts at DAN It contains a single 415 L cylinder (41 minutes supply at 10 L/min. (DAN kits now primarily use an aluminum Jumbo D (636.8 Liters; approximately 50 minutes of gas supply for a demand inhalator)), a demand valve delivery oxygen system for breathing patients and a pocket mask for non-breathing patients. This kit represents the current state of the art for dealing with oxygen administration in a serious diving emergency. As such, the DAN kit (or its equivalent) represents the minimal amount of oxygen equipment that should be present on dive training sites. Dive training should NOT, in my opinion, occur with anything less than this equipment on site. Since many divers dive or train in remote locations and are more than 30 minutes from medical assistance, a second (or more) 415 L (or larger) cylinder is desirable. Divers should have enough gas supply on hand to treat an injured diver for the amount of time it takes for the local site professional emergency response team to travel to the dive site.
INSTRUCTORS PLEASE NOTE: In the US, the DAN oxygen kit is considered the standard-of-care in the diving community for treatment of diving accidents. To train with less than this is a liability risk that you should be unwilling to assume!
3. A reasonable emergency alternative to the demand system, would be one (or more) D or E cylinder, a variable flow (15 L/min) medical oxygen regulator, a high concentration (non-rebreathing) oxygen delivery mask for breathing patients, and either the Laerdal or single-use modification pocket mask described above for a non-breathing patient. I tell my students to carry a non-rebreather mask in their traveling first aid kit. So, if they are in a situation where the only oxygen supply is constant flow and a simple facemask, substitution of the non-rebreather mask for the simple facemask can immediately boost the oxygen concentration given to the patient.
4. For those who already have oxygen cylinders and possibly some oxygen administration equipment, possible additions include:
a. A demand valve and mask with appropriate first stage. Consult your local hospital supply vendor or DAN for advice. Many of these devices contain a lever or trigger for positive pressure mechanical ventilation. If your demand system has a trigger, do not use this trigger unless you have received training in its use. Improper use (especially with older mechanical ventilators) could damage patient's lungs and lead to increased patient injury or death.
b. For those who already have an oxygen regulator capable of delivering 15 L/min and cannot afford a demand mask, a non-rebreathing mask (Hudson # 1059, or equivalent) is a necessary alternative. This mask properly used, will deliver about 60 - 70 % oxygen at 15 L/min. The mask sells for between $ 3 - 6. But remember, for denitrogenation we need the highest possible concentration of oxygen, so, although this system is better than nothing, all efforts should be made to supply accident management kit with a demand system.
c. One of the pocket mask assemblies described above.
d. A rugged carrying case to protect the oxygen unit from rough handling and the environment. Cases with O-rings to insure watertight integrity are recommended for use in marine environments.
Local hospital supply vendors or DAN can be exceptionally helpful to you when you assemble the oxygen administration portion of your emergency response kit. Make certain that you discuss your needs with a respiratory therapist, not just a salesperson. Explain that your oxygen use will be emergency field management of a scuba diving injury, and that your desire is to furnish the highest possible concentration of oxygen with only a limited supply of gas to a scuba diving accident victim. They may also inform you about any local legal restrictions on oxygen equipment or utilization. Note that oxygen used in aircraft, in very small cylinders (like those sold by mail-order), or by rescue personnel for emergency use only are exempt from prescription requirements. (Many local vendors, however, will be more comfortable if you obtain a prescription for your oxygen unit. My personal prescription states that the oxygen unit is only for emergency applications in a diving accident.) Regardless of what you decide to carry in your emergency response kit, remember that people save lives; equipment merely helps. (In an emergency, divers should utilize whatever is available to the best of their abilities within the limitations of their training and the tools assembled.) All the above equipment is useless; unless you (and your buddy) know how to use the life saving tools you will carry with you to the dive site. Thus, you should seek out the training of a knowledgeable dive rescue or oxygen administration instructor who can teach you the proper use of oxygen administration devices. Oxygen administration is a skill that can be easily learned, under proper supervision. Practice now could prevent a later problem from becoming a catastrophe.
Friday, 8 August 2008
The scuba agency debate
Rummaging through some old papers, I came across a certificate issued to me by my first dive instructor. A ‘One Star’ sport diver certificate issued by the South African Underwater Union enabling me to dive up to a maximum depth of 15 meters – this was way back in 1983.
The certificate got me thinking about what probably is one of the most commonly asked questions by those considering diving. That is, "what is the best SCUBA certification agency?"
So which one is best? And, "will a certification with one agency limit me in any way?"
Most people seem to feel and believe that it's not so much the agency that's important - it's the instructor that makes the difference. The general consensus is that all of the major organizations are qualified to provide the materials and certifications. But keep in mind that the organization does not teach you to dive - the instructor does. Thus, it's important to find an instructor that is truly qualified, that presents the material thoroughly, and that makes you feel safe in the water.
Potential students seldom ask any questions beyond price. As the old saying goes, "You get what you pay for." Excellent instructors will usually have a higher priced class for a number of reasons. The instructor is dedicated toward providing you all the time you need to master necessary knowledge and skills. Extra time can be expensive. Keep in mind; the instructor is trying to make a living. His time is valuable.
When selecting a service provider (instructor) question the following:
How long has the instructor been teaching?
Most instructors improve over time. They learn new techniques and get ideas from other instructors and through experience improve their classes.
Do they certify all their students?
Only instructors who are in a hurry and care nothing about your safety will answer yes. You want an instructor who will require you to be safe and knowledgeable before issuing a certification card. An excellent instructor might tell you that he is willing to keep working with a student until the student either qualifies or gives up.
Do their students swim with their hands?
This will let you know if the instructor pays attention to details. Good divers do not use their hands for swimming. Divers should be horizontal in the water. Good instructors will see that students are striving towards good trim. Poor instructors often neglect it.
What method do they use to correctly weight their students?
Any answer that does not involve actually getting in the water means you want to avoid that instructor. Many instructors overweight students which is not a good practice.
How many students in the class?
Small classes are better. You'll have more individual attention. Unless the instructor is using assistants, more than four students are difficult to watch.
Finally ask yourself the following:
Is the instructor patient?
While talking with your potential instructor, you should be getting a feel for his personality. Patience is an important quality for an instructor. You want to avoid instructors with a drill sergeant demeanor.
Would I be happier learning from a man or a woman?
Only you can answer that question, but in general it is not usually a serious consideration. There are excellent instructors and there are poor instructors. Men and women fall into both groups.
The certificate got me thinking about what probably is one of the most commonly asked questions by those considering diving. That is, "what is the best SCUBA certification agency?"
So which one is best? And, "will a certification with one agency limit me in any way?"
Most people seem to feel and believe that it's not so much the agency that's important - it's the instructor that makes the difference. The general consensus is that all of the major organizations are qualified to provide the materials and certifications. But keep in mind that the organization does not teach you to dive - the instructor does. Thus, it's important to find an instructor that is truly qualified, that presents the material thoroughly, and that makes you feel safe in the water.
Potential students seldom ask any questions beyond price. As the old saying goes, "You get what you pay for." Excellent instructors will usually have a higher priced class for a number of reasons. The instructor is dedicated toward providing you all the time you need to master necessary knowledge and skills. Extra time can be expensive. Keep in mind; the instructor is trying to make a living. His time is valuable.
When selecting a service provider (instructor) question the following:
How long has the instructor been teaching?
Most instructors improve over time. They learn new techniques and get ideas from other instructors and through experience improve their classes.
Do they certify all their students?
Only instructors who are in a hurry and care nothing about your safety will answer yes. You want an instructor who will require you to be safe and knowledgeable before issuing a certification card. An excellent instructor might tell you that he is willing to keep working with a student until the student either qualifies or gives up.
Do their students swim with their hands?
This will let you know if the instructor pays attention to details. Good divers do not use their hands for swimming. Divers should be horizontal in the water. Good instructors will see that students are striving towards good trim. Poor instructors often neglect it.
What method do they use to correctly weight their students?
Any answer that does not involve actually getting in the water means you want to avoid that instructor. Many instructors overweight students which is not a good practice.
How many students in the class?
Small classes are better. You'll have more individual attention. Unless the instructor is using assistants, more than four students are difficult to watch.
Finally ask yourself the following:
Is the instructor patient?
While talking with your potential instructor, you should be getting a feel for his personality. Patience is an important quality for an instructor. You want to avoid instructors with a drill sergeant demeanor.
Would I be happier learning from a man or a woman?
Only you can answer that question, but in general it is not usually a serious consideration. There are excellent instructors and there are poor instructors. Men and women fall into both groups.
Friday, 1 August 2008
First Aid Kits
First Aid Kits can be purchased ready made or can be made up to your own personal specification. The components are a matter of personal choice but the kit should contain sufficient items for the size of the party and appropriate to the activity undertaken.
In addition to carrying a first aid kit, service providers are also required to provide 100% Oxygen with a flowrate of 15 litres per minute for a minimum of 20 minutes, as well as a stretcher when shore or boat diving.
Here’s a list of contents of my first aid kit which is by no means exhaustive but gives you an idea of the sort of things you may wish to include in your kit. The kit is always prominently displayed and freely available for use by qualified persons at the dive site.
Enclosing a list of contents in your first aid kit enables you to replenish any expired or used items.
First aid contents
Checked on: ___ ___ ____
Use personal barriers and note any items depleted to enable restocking
• Ammonia (After Bite-for stings)
• Ammonia Inhalant Ampoules
• Bandages (Normal & Triangular)
• Betadine (Disinfectant for wounds)
• Blanket
• Cold Compress (Sprains)
• Cotton-Tipped Applicators
• Cotton Wool
• Emergency Contact Numbers
• Emergency Reference Notes - Post It Notes / Pencil
• Eye Bath
• Eye Wash Saline Solution
• Gauze Swabs
• Gloves (Nitrile)
• Hansaplast Tape
• Inflatable Arm & Leg Splint (Adult)
• Pocket Mask
• SAM Splint
• Scissors: Paramedic & Hemostat (Curved)
• Stethoscope
• Sterile Saline Spray (Cleaning wounds)
• Stretcher (Portable)
• Torch
• Transparent Tape
• Tylenol Tablets
• Thermometer
• Uni Heat
In addition to carrying a first aid kit, service providers are also required to provide 100% Oxygen with a flowrate of 15 litres per minute for a minimum of 20 minutes, as well as a stretcher when shore or boat diving.
Here’s a list of contents of my first aid kit which is by no means exhaustive but gives you an idea of the sort of things you may wish to include in your kit. The kit is always prominently displayed and freely available for use by qualified persons at the dive site.
Enclosing a list of contents in your first aid kit enables you to replenish any expired or used items.
First aid contents
Checked on: ___ ___ ____
Use personal barriers and note any items depleted to enable restocking
• Ammonia (After Bite-for stings)
• Ammonia Inhalant Ampoules
• Bandages (Normal & Triangular)
• Betadine (Disinfectant for wounds)
• Blanket
• Cold Compress (Sprains)
• Cotton-Tipped Applicators
• Cotton Wool
• Emergency Contact Numbers
• Emergency Reference Notes - Post It Notes / Pencil
• Eye Bath
• Eye Wash Saline Solution
• Gauze Swabs
• Gloves (Nitrile)
• Hansaplast Tape
• Inflatable Arm & Leg Splint (Adult)
• Pocket Mask
• SAM Splint
• Scissors: Paramedic & Hemostat (Curved)
• Stethoscope
• Sterile Saline Spray (Cleaning wounds)
• Stretcher (Portable)
• Torch
• Transparent Tape
• Tylenol Tablets
• Thermometer
• Uni Heat
Monday, 21 July 2008
Formulating an Emergency Action Plan
When formulating an Emergency Action Plan many factors should be considered. While it is impossible to anticipate all emergencies, prior planning and proper training are key to dealing with emergency situations. Personnel must act quickly and effectively to minimize injury and/or prevent death. The following guidelines provide a planning tool which, when used properly, will allow an Emergency Action Plan to be developed and in place prior to the start of diving activities.
Emergency Numbers and Information
* Number of EMS and nearest hospital phone and location
* Location and contact information for nearest recompression chamber
* Number of poison control
* DAN emergency number
* Emergency contact information for divers
Equipment Requirements at Location
* Oxygen kit
* First Aid kit
* Pen and paper
* Forms
* Lines for search/recovery
* Backboard, stretcher, etc.
* Communications equipment (VHF, cellular phone, pay phone, CB radio, etc.)
* Flares and signaling devices
* Additional site specific equipment
Personnel Considerations
* Team members backgrounds and personalities
* Who will be in charge of what?
Site considerations
* Marine life
* Entrapments or entanglements
* Physical Hazards
* Depth
* Currents
Action Plan
* Emergency Recognition / Activation of Emergency Action Plan
* How to recall divers and alert personnel
* Search for and recover injured / missing diver
* Spotting Team
* Search and Recovery Team
* Individual to get help
* In-water evaluation and response (airway & breathing)
* Transport to platform or beach
* Extrication from water
* Evaluation and ABCD's
* Activation of EMS (ambulance, Coast Guard. etc.)
* Appropriate first aid (CPR, Oxygen, Shock treatment, etc.)
* Gather information (diver, buddy, equipment, observer)
* Evacuation procedures
* Evacuation mode/route
* Call DAN if appropriate
* Provide info and accompany EMS (inform them compressed gas was used)
* Follow up and reporting procedures
Helicopter Evacuation Procedures
Each helicopter evacuation is different, each one presents its own problems, but knowing what to expect and the procedures to follow can save time, effort, and perhaps a life.
* If your boat is unable to provide the required frequency, work via another
* Maintain speed of 10 to 15 knots, do not slow down or stop
* Maintain course into wind about 20 degrees on port bow
* Put all antennas down if possible, without losing communications
* Secure all loose objects on/or around decks
* Always let the lifting device touch the boat before handling it
* Place lift jacket on patient
* Tie patient in basket, face up
* Provide as much information as you can about patient (casevac form)
* Ensure flight crew is instructed on medical procedures for diving accidents
* Ensure flight crew delivers victim to hyperbaric chamber
* If patient dies, inform flight crew so that they take no unnecessary risks
Obviously, a dive accident plan can vary substantially from site to site. Regardless of the site, the emergency accident plan and contingency plans should be formulated and made clear to the dive team. It often helps to visualize a worst case scenario. On-site accident drills are recommended to illustrate roles, required actions and potential problems.
Emergency Numbers and Information
* Number of EMS and nearest hospital phone and location
* Location and contact information for nearest recompression chamber
* Number of poison control
* DAN emergency number
* Emergency contact information for divers
Equipment Requirements at Location
* Oxygen kit
* First Aid kit
* Pen and paper
* Forms
* Lines for search/recovery
* Backboard, stretcher, etc.
* Communications equipment (VHF, cellular phone, pay phone, CB radio, etc.)
* Flares and signaling devices
* Additional site specific equipment
Personnel Considerations
* Team members backgrounds and personalities
* Who will be in charge of what?
Site considerations
* Marine life
* Entrapments or entanglements
* Physical Hazards
* Depth
* Currents
Action Plan
* Emergency Recognition / Activation of Emergency Action Plan
* How to recall divers and alert personnel
* Search for and recover injured / missing diver
* Spotting Team
* Search and Recovery Team
* Individual to get help
* In-water evaluation and response (airway & breathing)
* Transport to platform or beach
* Extrication from water
* Evaluation and ABCD's
* Activation of EMS (ambulance, Coast Guard. etc.)
* Appropriate first aid (CPR, Oxygen, Shock treatment, etc.)
* Gather information (diver, buddy, equipment, observer)
* Evacuation procedures
* Evacuation mode/route
* Call DAN if appropriate
* Provide info and accompany EMS (inform them compressed gas was used)
* Follow up and reporting procedures
Helicopter Evacuation Procedures
Each helicopter evacuation is different, each one presents its own problems, but knowing what to expect and the procedures to follow can save time, effort, and perhaps a life.
* If your boat is unable to provide the required frequency, work via another
* Maintain speed of 10 to 15 knots, do not slow down or stop
* Maintain course into wind about 20 degrees on port bow
* Put all antennas down if possible, without losing communications
* Secure all loose objects on/or around decks
* Always let the lifting device touch the boat before handling it
* Place lift jacket on patient
* Tie patient in basket, face up
* Provide as much information as you can about patient (casevac form)
* Ensure flight crew is instructed on medical procedures for diving accidents
* Ensure flight crew delivers victim to hyperbaric chamber
* If patient dies, inform flight crew so that they take no unnecessary risks
Obviously, a dive accident plan can vary substantially from site to site. Regardless of the site, the emergency accident plan and contingency plans should be formulated and made clear to the dive team. It often helps to visualize a worst case scenario. On-site accident drills are recommended to illustrate roles, required actions and potential problems.
Friday, 18 July 2008
Risk assessment - what's it all about?
Service providers are responsible for ensuring that before the start of any diving activity, a suitable generic risk assessment has been prepared. Generic risks are those that we have fore knowledge of and can therefore put control measures in place in advance of the activity. These generic risk assessments should be supplemented with an on site risk assessment immediately before the dive, detailing any previously unforeseen hazards and the special precautions or procedures necessary to reduce the risks; as well as re-evaluating those on the generic risk assessment.
Differences between a 'hazard' and a 'risk':
A hazard is anything with the potential to cause harm. A risk is defined as the liklihood that someone or something would be harmed by the hazard.
Hazards and risks should be continuously monitored during any dive or diving related activity. Dive Leaders should be prepared to put any contingency plans into place at any point during the dive.
A Risk Assessment is nothing more than a common sense approach to identifying significant hazards; who or what is likely to be affected by those hazards; the risks associated with those hazards and what measures you will take to control the risks thereby reducing the harm to anyone or anything during any dive or diver training operation, and then recording what you have done. You will need to review the assessment periodically or whenever there is significant change. The important thing to decide is whether an identified hazard is significant, and whether you can ensure the risk of harm is low or negligible before embarking on your dive.
Risk assessment is already inherent in the way divers go about organising their diving and training through careful dive preparation and planning. The consideration of risk inherent in diver training and supervised dives is already paramount in all diver training organisations' course contents, standards and procedures.
A Risk Assessment is simply a way of recording the significant hazards and what measures you will take to reduce the risk of harm on each and every dive. Don't be over complicated.
Checking for hazards is common sense. In taking action, ask yourself these two questions:
Can I get rid of the hazard altogether? If not, how can I control the risks so that harm is unlikely?
For example:
Risk of: Cold water
Hazard: Hypothermia
Risk control measures: Choose appropriate, well fitting exposure protection in good order; reduce dive time; monitor student divers carefully for early signs of cold; brief student divers on appropriate signals to indicate chill; prepare to exit water early if necessary; have warm clothing and shelter available at the site.
Diving is inherently a hazardous activity; however, the known risks are already minimised to some degree by adherence to your diver training organisations' standards and procedures, e.g. the likelihood of a diver having a mask squeeze is minimised as mask equalisation techniques are taught to all divers in the earliest stages of training. This is therefore no longer a significant hazard as the control measure is in place whilst adhering to your diver training organisations' course contents, standards and procedures.
Differences between a 'hazard' and a 'risk':
A hazard is anything with the potential to cause harm. A risk is defined as the liklihood that someone or something would be harmed by the hazard.
Hazards and risks should be continuously monitored during any dive or diving related activity. Dive Leaders should be prepared to put any contingency plans into place at any point during the dive.
A Risk Assessment is nothing more than a common sense approach to identifying significant hazards; who or what is likely to be affected by those hazards; the risks associated with those hazards and what measures you will take to control the risks thereby reducing the harm to anyone or anything during any dive or diver training operation, and then recording what you have done. You will need to review the assessment periodically or whenever there is significant change. The important thing to decide is whether an identified hazard is significant, and whether you can ensure the risk of harm is low or negligible before embarking on your dive.
Risk assessment is already inherent in the way divers go about organising their diving and training through careful dive preparation and planning. The consideration of risk inherent in diver training and supervised dives is already paramount in all diver training organisations' course contents, standards and procedures.
A Risk Assessment is simply a way of recording the significant hazards and what measures you will take to reduce the risk of harm on each and every dive. Don't be over complicated.
Checking for hazards is common sense. In taking action, ask yourself these two questions:
Can I get rid of the hazard altogether? If not, how can I control the risks so that harm is unlikely?
For example:
Risk of: Cold water
Hazard: Hypothermia
Risk control measures: Choose appropriate, well fitting exposure protection in good order; reduce dive time; monitor student divers carefully for early signs of cold; brief student divers on appropriate signals to indicate chill; prepare to exit water early if necessary; have warm clothing and shelter available at the site.
Diving is inherently a hazardous activity; however, the known risks are already minimised to some degree by adherence to your diver training organisations' standards and procedures, e.g. the likelihood of a diver having a mask squeeze is minimised as mask equalisation techniques are taught to all divers in the earliest stages of training. This is therefore no longer a significant hazard as the control measure is in place whilst adhering to your diver training organisations' course contents, standards and procedures.
Friday, 11 July 2008
For Angeliki
A recent visit to Kalymnos inspired me to write this story and dedicate it to the wife of my dear friend Alex, on the occassion of her birthday.
‘Greeks and the sea interpenetrate’, the Greek saying goes; and from ancient times young men of the Dodecanese have penetrated the sea in search of natural sponges 'the golden fleece of the sea'.
Until the 1860’s the Greek sponge divers used the ancient and proud technique of 'naked diving’. Today it's known as ‘breath-hold diving’.
Wearing only a net bag slung around his waist, and holding a flat marble stone of 15 Kgs in weight, the diver would shoot down an inclined plane jutting from the side of the boat into the water. He would then plummet to a depth of 70 meters, using the stone as a rudder to steer through his descent. Called a ‘bell stone’ on the island of Symi and a ‘trigger stone’ on the island of Kalymnos because of its function (it triggered the dive), the diving stone was a prized possession handed down from father to son.
The stone had a hole in one rounded end where a line was attached to the boat. On the bottom, if successful, a naked diver could gather one or two sponges in his net bag before tugging on the line, signalling he had to be pulled back to air. Like a sea bird, he would plunge and rise up through a twelve-hour working day, taking neither food nor water, apart from a little bread and coffee at daybreak.
In 1913, a naked diver from Symi rescued the lost anchor of the ‘Regina Margherita’, an Italian warship on her maiden voyage. He dove to a depth of 80 meters on a single breath of air and tied a rope around the anchor. Records show the dive as 3’35”.
In 1863 the Industrial Revolution arrived in the Dodecanese and brought with it swift and huge prosperity won at too terrible a price. The deep-sea diving suit was introduced into the sponge diving industry, and first on the island of Symi. Ironically, the suit - which the divers swiftly came to call ‘Satan’s machine’ - was introduced at a place of incomparable beauty, Symi’s harbour, perhaps being the most stunning in all of Greece.
The new suit allowed the diver to see, to remain underwater - it seemed indefinitely, and to descend to previously unobtainable depths. Needless to say, it increased the diver’s productivity one hundred-fold. As the new deep-diving suits, the ‘skafandra’ came into wide use, casualties mounted in the sponge-fishing islands. Between 1866 and 1895, on the island of Kalymnos alone, 800 young men died of the bends and 200 more were paralysed!
The Industrial Revolution had created an ever growing demand for soft and luxurious sponges for the great cities of Western Europe. Between 1880 and 1890, Symi was the wealthiest port in all the Mediterranean. In a single season, a merchant captain on Symi could earn an entire fortune, and the divers also shared in the bounty. A diver could earn two and half times in six months what a man of similar education could earn in a year.
It was the Golden Age of sponge fishing. All rested on a foundation of ever increasing demand and the increasing sponge yield that came with the ‘skafandra’- bigger boats, better pumps, and with the industrial organisation that now was brought to bear on the sponge fishing industry.
Each spring, in April and May, 300 sponge boats set sail from Kalymnos alone for the six month sponge fishing season that took divers along the coast of North Africa, from Alexandria to Benghazi. And the Kalymnian fleet was joined at sea by large sponge fishing fleets from other Dodecanese islands.
With the increased sponge yield came the destruction of the sponge beds-the harvesting exceeding the natural rate of re-growth. A vicious economic race had been set in motion-merchants demanded more sponges of the divers, and the divers demanded more of themselves in order to keep pace with the growing needs of a plentiful age that supplied silks and satins, Italian marble, French furniture, family portraits and exotic foodstuffs.
The known sponge beds thinned or were wiped out entirely. There was but one way, and that was the way down! Down beyond 50 m, down beyond 70 where even the Aegean daylight grows dim and faint, down to the darkness that their new diving suits made possible for them. But their diving suits were not made for 70m - they were designed for 30!
The awful stories abound: diving boats set sail from Kalymnos right after the joy of Greek Easter with 20 divers on board and returned in the autumn with 10; or left Kalymnos in the spring with 10 divers and returne with none.
One Sunday in May 1895, the news came early that season of many deaths, the women of Kalymnos spontaneously performed the anathema against all merchant captains as women poured out from churches all over the island. Violent protests against the ‘skafandra’ took place in Symi and Kalymnos, sometimes led by women. Intellectuals and theologians arrayed themselves against the merchants and the captains. Bans of fleeting duration were issued, one lasting two years. On the island of Symi the sponge industry had become known as ‘The tyranny’. When the sponge fleet arrived home in Symi in October - after been gone for six months - the women would race to the shore to greet the returning fleet; in solidarity all of the women dressed in black, not knowing who among them would be widows.
Since high casualty rates continued until the 70’s - long after divers knew about proper diving techniques - one often asks the question ‘why’?
It all had to do with a prepayment system, which created the pressure to dive with dangerous disregard to safety. Since the divers may never return, they could command 100 per cent of their six months’ wages in advance of sailing. Since so much money had exchanged hands, divers were under enormous pressure (both self imposed and by captains who now owned them to harvest enough sponge) to match the high prepayment they had received.
We know the causes - the list includes poor equipment, ignorance of proper diving techniques, greed, and the truth that these beautiful rock strewn islands had only the sea to turn to and what the sea so reluctantly gave up.
Monday, 7 July 2008
Emergency Contact Numbers & Hyperbaric Chambers
Emergency numbers
Ambulance 166
Coastguard 108
European Emergency Service 112
Hospitals on Duty 1434
Poison Control Center (Athens) 2107793777
Police 100
Tourist Police 171
Hyperbaric Chambers
Hyperbaric Medical Center (Athens) 2103462898
Kalymnos Chamber 2243061900
Metropolitan Hospital (Piraeus) 2104809337
Naval Hospital (Athens) 2107216166
Souda Naval Base (Crete) 2821089307
Thessaloniki Chamber 2310493407
Ambulance 166
Coastguard 108
European Emergency Service 112
Hospitals on Duty 1434
Poison Control Center (Athens) 2107793777
Police 100
Tourist Police 171
Hyperbaric Chambers
Hyperbaric Medical Center (Athens) 2103462898
Kalymnos Chamber 2243061900
Metropolitan Hospital (Piraeus) 2104809337
Naval Hospital (Athens) 2107216166
Souda Naval Base (Crete) 2821089307
Thessaloniki Chamber 2310493407
Wednesday, 2 July 2008
What about restrictions regarding recreational scuba diving in Greece?
The new recreational scuba diving law now permits diving everywhere in Greece, except in the following instances:
• diving in shipping lanes or anchorages
• areas where naval and/or armed forces carry out exercises or other activities
• areas where hired motorboats can travel 100 meters or less from their starting point
• areas where prohibitions have been imposed by legislation that designates marine areas as protected, or by the administrative and operational regulations or plans of competent administrative authorities
• where there are underwater cables or systems installed by utility companies
• wherever the Coastguard Authority, in a duly justified decision, imposes prohibitions for reasons of safety of ships or personnel
• recreational dives, where not conducted under the services of a Recreational Services Diving Provider, are prohibited from one hour after sunset and up to one hour before sunrise
• scuba diving is prohibited to persons who do not have a certification recognised by an Organisation under article 3 and not under the services of a Recreational Diving Service Provider.
Organisations currently recognised include: ANDI, PADI, IANTD, The Greek Diving Federation, NAUI & SSI
Scuba divers are also forbidden to:
• fish with a spear gun or other means; collect, disturb or destroy individual members of micro-flora and micro-fauna, flora and fauna or commit any acts which might alter or corrupt ecological interaction in the eco-system of the area
• carry underwater fishing equipment or fish or other animal or vegetable marine organisms on a ship or vessel which accompanies them
• haul up, transport or photograph artefacts of archaeological or other value found in the deep
• take photographs or videos in areas where diving is prohibited unless there is written permission from the competent ministry
• dive without being accompanied by another diver
• all divers are to inform the competent Coastguard Authority immediately and by all possible means if they locate objects of archaeological or police interest or shipwrecks
• flag Alpha as described in Chapter 11 of the International 1969 Signals Code, or the internationally recognised diving flag (red with a diagonal white line) is to be flown from the diver’s boat
• divers who venture further than a horizontal distance of 50 meters from the boat which is accompanying them, or who dive from the shore, are obliged to display an orange-coloured float on the surface, with the special sign or internationally recognised flag mentioned in the previous paragraph and all vessels are to remain more than 100 meters from the location of the special sign or internationally recognised flag
• diving in shipping lanes or anchorages
• areas where naval and/or armed forces carry out exercises or other activities
• areas where hired motorboats can travel 100 meters or less from their starting point
• areas where prohibitions have been imposed by legislation that designates marine areas as protected, or by the administrative and operational regulations or plans of competent administrative authorities
• where there are underwater cables or systems installed by utility companies
• wherever the Coastguard Authority, in a duly justified decision, imposes prohibitions for reasons of safety of ships or personnel
• recreational dives, where not conducted under the services of a Recreational Services Diving Provider, are prohibited from one hour after sunset and up to one hour before sunrise
• scuba diving is prohibited to persons who do not have a certification recognised by an Organisation under article 3 and not under the services of a Recreational Diving Service Provider.
Organisations currently recognised include: ANDI, PADI, IANTD, The Greek Diving Federation, NAUI & SSI
Scuba divers are also forbidden to:
• fish with a spear gun or other means; collect, disturb or destroy individual members of micro-flora and micro-fauna, flora and fauna or commit any acts which might alter or corrupt ecological interaction in the eco-system of the area
• carry underwater fishing equipment or fish or other animal or vegetable marine organisms on a ship or vessel which accompanies them
• haul up, transport or photograph artefacts of archaeological or other value found in the deep
• take photographs or videos in areas where diving is prohibited unless there is written permission from the competent ministry
• dive without being accompanied by another diver
• all divers are to inform the competent Coastguard Authority immediately and by all possible means if they locate objects of archaeological or police interest or shipwrecks
• flag Alpha as described in Chapter 11 of the International 1969 Signals Code, or the internationally recognised diving flag (red with a diagonal white line) is to be flown from the diver’s boat
• divers who venture further than a horizontal distance of 50 meters from the boat which is accompanying them, or who dive from the shore, are obliged to display an orange-coloured float on the surface, with the special sign or internationally recognised flag mentioned in the previous paragraph and all vessels are to remain more than 100 meters from the location of the special sign or internationally recognised flag
Subscribe to:
Posts (Atom)
