scubadoc Ten Foot Stop

March 10, 2008

UNDERCURRENT ONLINE UPDATE

Filed under: Interesting Newsscubadoc @ 9:38 am


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Undercurrent — Consumer Reporting for
the Scuba Diving Community since 1975
www.undercurrent.org

Dive News

March 10, 2008

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Diver Dies From Shark Bite in the Bahamas : By now, you have surely read about 49-year-old Austrian Markus Groh who died from a shark bite during a Bahamas shark-diving liveaboard trip with Jim Abernathy’s Scuba Adventures. For years, Abernathy has been offering cage-free dives with hammerheads, tiger and bull sharks that Abernathy attract with chum. Undercurrent will write more about this in the April issue, but the question of liability will be a big one. Apparently, Groh signed a standard waiver releasing Abernathy from liability - the kind we divers hate to sign. While waivers have held up well in court, with the high profile of this death, expect an all-out attack on the waiver’s validity. In a letter last year from the Bahamas Dive Association, all companies operating in Bahamas waters were told to cease and desist openwater, non-cage shark diving with potentially dangerous sharks. Neal Watson, the association’ president, confirmed the letter was targeted at Abernathy’s company, which was viewed as an “accident waiting to happen”. Abernathy has refused to comply. In the March issue of Undercurrent, we write about this topic in “Please Don’t Feed the Fish” — subscribe to Undercurrent and you can read about the hazards of fish-feeding and shark-baiting.

Oceanic Wilderness : Mysteries of the Silent Deep. This new book by Roger Steene is among the best book of underwater photographs ever published. He has captured unique behaviors of unique creatures - like a harlequin shrimp devouring a sea star — with an unprecedented level of color and camouflage. Steene has a scientific eye that goes far beyond most professional photographs, which results in an endless array of surprising and stunning shots. More than 500 images fill the 340 pages of this oversized coffee-table book. A must for your library. 13 x 11 inches, hardcover, $60, however order it at www.undercurrent.org for Amazon’s deeply discounted price and our profits will go to save coral reefs.

Dive with Stan Waterman : The Emmy Award-winning filmmaker will be on four week-long dive trips with the Aggressor Fleet this year. Join him aboard the Belize Aggressor May 10 to 17; the Palau Aggressor July 13 to 20; the Cayman Aggressor July 26 to August 2; and the Turks & Caicos Aggressor on October 11 to 18. For more information, go to www.aggressor.com

Turks & Caicos Residents Says New Hotel Killing Reefs : Locals on Providenciales are protesting the construction of the Nikki Beach Resort because it is dredging thousands of tons of sand from the seabed to allow boats up to 200 feet long to pass through. That is leading silt to settle on and smother the coral. Jay Stubbs, owner of Sail Provo, told British newspaper The Telepgraph, “There are places we used to take guests snorkeling which we can’t go to anymore. Just last year you could see the bottom, now it’s so murky even the turtles can’t find their way down.” Nikki Beach Resort is scheduled to open this month.

Scuba-Diving Pot Kingpin Goes to Jail : Garry C. Chupurdy, 58, of Thunderbolt, Georgia pleaded guilty last month for running a marijuana smuggling operation in which he sank tons of pot, then brought it to the surface later using GPS and scuba gear. Chupurdy made yearly trips to Jamaica in his 78-foot catamaran Cat’s Meow. On the return voyage, he packaged marijuana in air tight, vacuum-sealed plastic bags and sunk them in shallow waters 30 miles off the coasts of South Carolina and Georgia. Chupurdy then returned in a small motorboat, located the packages with GPS and dived down to retrieve them. He smuggled 1,500 pounds on one trip in May 2006, and 2,000 pounds in June 2007. Chupurdy was sentenced to 18 years in prison.

Google Finds New Reefs : The computer tool Google Earth was responsible for the discovery of rare fringing coral reefs in Western Australia’s remote Kimberly region. Chris Simpson, a coral reef specialist at West Australia’s Department of Conservation, was viewing Google Earth satellite pictures of the Kimberly on his PC and spotted the never-before-seen reefs. Fringing coral reefs are rare and found only in a few places like the Red Sea, Madagascar and Western Australia’s Ningaloo Marine Park. Simpson’s discovery now makes the Kimberley a better candidate for marine park status.

This Month’s Free Article : Every month, we always make at least one of our articles free for the public to read. In the March issue, we share some subscribers’ reports about dive trips from around the world, from Roatan to Oman. One of the benefits of being an Undercurrent subscriber is finding out what fellow readers have to say about their dive experiences — and sharing your own. Read the March trip reports for free by clicking on “Barbados, Oman, Puget Sound, Samoa,” listed in “The March Issue” at www.undercurrent.org.

Upcoming Articles : What we’re working on for future issues:
* Cebu, Phillipines
* Andros Island, Bahamas
* The Letty, Galapagos Islands
* Tipping on dive trips: how much and for whom
* Why divers die: Part III - dumb errors turned into fatal mistakes


Ben Davison, editor/publisher
PublisherBenD@undercurrent.org 

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March 9, 2008

Dehydration and Diving

Filed under: Interesting Newsscubadoc @ 11:43 am

Dehydration Defined

Dehydration means your body does not have as much water and fluids as it should. Dehydration can be caused by losing too much fluid, not drinking enough water or fluids, or both. Vomiting and diarrhea are common causes. Pressurized airplane cabins, scuba air, alcoholic and other diuretic drinks, diuretic medications and certain medical conditions such as diabetes can cause dehydration.

Children divers are more susceptible to dehydration than adults because of their smaller body weights and higher turnover of water and electrolytes. The elderly and those with illnesses are also at higher risk.

Dehydration is classified as mild, moderate, or severe based on how much of the body’s fluid is lost or not replenished. When severe, dehydration is a life-threatening emergency. It is a known hazard to divers by increasing the risk for decompression illness.

Some of the smptoms of dehydration include:

* Dry or sticky mouth
* Low or no urine output; concentrated urine appears dark yellow
* Not producing tears
* Sunken eyes
* Lethargic or comatose (with severe dehydration)

Signs and tests indicating dehydration include:

A physical examination may also show signs of:

* Low blood pressure
* Blood pressure that drops when you go from lying down to standing
* Rapid heart rate
* Poor skin turgor — the skin may lack its normal elasticity and sag back into position slowly when pinched up into a fold by the doctor; normally, skin springs right back into position
* Delayed capillary refill
* Shock

Tests include:

* Blood chemistries (to check electrolytes, especially sodium, potassium, and bicarbonate levels)
* Urine specific gravity (a high specific gravity indicates significant dehydration)
* BUN (blood urea nitrogen — may be elevated with dehydration)
* Creatinine (may be elevated with dehydration)
* Complete Blood Count (CBC) to look for signs of concentrated blood

Other tests may be done to determine the specific cause of the dehydration (for example, a blood sugar to check for diabetes).
Diuretics

Diuretics add to the dehydration that occurs with exercise from  sweating, insensible and respiratory water loss; the diver also has to take into consideration some additional concerns for fluid loss and replacement.

1. Scuba tanks have extremely dry air inside. As this air is taken into the lungs and saturated–nearly twice the normal amount of water is lost from the body.

2. Negative pressure breathing causes divers to lose about 350 cc/hour from their circulating blood volume, a phenomenon called immersion diuresis and seen also in snorkelers and swimmers.

3. Cold inhibits anti diuretic hormone, causes peripheral vasoconstriction, driving fluid back into the core and stimulating diuresis resulting in losses of plasma volume.

4. The hypercarbia (high blood carbon dioxide) associated with diving decreases anti diuretic hormone, promoting fluid loss from the plasma volume.

5. Diuretics such as alcohol, coffee, tea also contribute to fluid losses, contributing to predive dehydration.

6. Khosla in 1979 found that there is a 4% hemodilution in early immersion from ECF (extracellular fluid) shift into the bloodstream, resulting in an increase in central blood volume. This alters stimulation of pressure and volume receptors, leading to further inhibition of ADH (anti-diuretic hormone) and fluid loss.

7. In addition to the above, the state of chronic hypovolemia (low fluid vloume) and hypokalemia (low serum potassium) caused by oral diuretics is dangerous to divers by increasing their susceptibility to decompression illness and cardiac arrhythmias, respectively.

A good start in reading about this problem would be in “Diving Medicine”, Bove and Davis, Philadelphia, WB Saunders, 1990, ed 2.

Also try Edmonds C., Lowry C, Pennefather J.:Diving and Subaquatic Medicine.
Oxford, Butterworth-Heinemann, 1992,ed 3., and  Bennett and Elliott (Eds): The Physiology and Medicine of Diving. London, WB Saunders, 1993, ed 4.

The importance of entering a dive well-hydrated cannot be over-stated. Prehydration of divers should include regular ingestion of fluids several hours before, 15-20 minutes before and between dives, particularly if multiple dives are to be made each day. The urine should be “clear and copious”, the urine test for divers proposed by Dr. Jeff Davis.

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March 7, 2008

Office of Naval Research Provides $3.5 Million in New Grants for Clinical Research Involving Oxycyte(R), DCS and Arterial Gas Embolism

Filed under: Interesting Newsscubadoc @ 11:28 am

COSTA MESA, Calif. — Synthetic Blood International, Inc. (OTCBB:SYBD) announced today that Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES) has received four separate research grants from the Office of Naval Research (ONR) totaling $3,517,696. These four grants will support pre-clinical research studies involving Oxycyte(R), a product of Synthetic Blood International. Oxycyte is the company’s perfluorocarbon (PFC) therapeutic oxygen carrier and blood substitute.

Bruce Spiess, M.D., Virginia Commonwealth University Professor of Anesthesiology and Emergency Medicine, Director of Research (Anesthesiology) and Director of VCURES said, “These grants will allow us to expand upon the previous studies which showed that early intervention with Oxycyte can prevent the destruction of nerve cells, brain tissue in a number of conditions including decompression illness and gas embolism.”

http://www.centredaily.com/business/technology/story/450151.html

March 6, 2008

Larry “Harris” Taylor’s Dive Links

Filed under: Interesting Newsscubadoc @ 10:44 am
This month’s additions, re-appearances, and bunches of updated/re-directs this month to my list of about 8000 links at 
Diving

Insurance-Witherspoon: http://www.scubainsurance.net/
 
WPMC Hyperbaric Medicine: http://www.wpafb.af.mil/units/wpmc/
Scuba Doc-Ten Foot Stop News Blog: http://www.scuba-doc.com/tenfootstop/
 
 
 
 
 
Scuba Diving Channel: http://www.scubadivingchannel.tv/
Not-Diving, but still interesting:
 
Environmental Stewardship: http://www.med.umich.edu/envsteward


Defense Technical Info Center Search: http://www.dtic.mil/
 
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Ghosts of the abyss: the story of Don Shirley and Dave Shaw

Filed under: Interesting Newsscubadoc @ 10:23 am

Here is an interesting story that will keep you on edge.

When Don Shirley and Dave Shaw discovered the corpse of a diver, missing for 10 years, in the depths of a South African cave, they knew they had to bring it back - even if it meant returning to the ‘dead zone’ 270m down, where few divers have ever ventured.

http://tinyurl.com/2f3k4b

March 5, 2008

Dry Diving

Filed under: Interesting Newsscubadoc @ 5:06 pm

If you didn’t have decompression sickness and entered a recompression chamber for treatment or demonstration purposes, would there be any medical problems due to hyperbaric treatment when it was not needed?
Treating decompression illness (decompression sickness and arterial gas embolism) is just one of the uses for recompression chambers. They are now being used to treat quite a few other illnesses. In the United States, chamber treatment is approved by Medicare for some 13 conditions.
Being compressed in a chamber is in essence a “dry dive” without the dangers of being in a watery, alien environment. You would, however, be subjected to the same risks of barotrauma to air-containing body spaces and the possibility of ear, lung and sinus problems. If 100 percent oxygen were being used, you would also be at risk of oxygen toxicity if the oxygen intervals and pressure were not properly controlled. “Older divers remember the ‘oxygen toxicity’ test dives - in days bygone there was the periodic oxygen tolerance test. It was finally decided that the test results were good for the day you took the test without much predictive value. (Glen Egstrom, PhD). Dry dives can be fun if you are in a group with a good sense of humor”.
The London Diving Chamber  < http://www.londondivingchamber.co.uk/ >  has a website that appears to be promoting a taste of Nitrogen Narcosis in the dry without risk of drowning or DCI. “It is not a bad idea to demonstrate a chamber to a trainee diver; this may both reassure but at the same time endorse the need to avoid an unscheduled visit - at a later date!”  (Dr. Nick McIver).
“Dry dives mimic some of the effects of diving, such as N2 narcosis and the increase in gas density. Indeed, much of what we know about diving physiology comes from experiments in dry chambers. However, neither equipment not humans behave exactly the same in the water as in the dry”. (Richard Moon, MD).
Captain Dick Carson, USN (Ret) (PADI Instr) recounts the following about ‘dry dives’. “Being a frequent diver at Stoney Cove near Birmingham in England, I was often amazed as the dive store there used their mini-chamber to assemble semi-dry suits. The near 1-inch thick neoprene suit was compressed while taking the store clerk “down” to the point the “Whites Valve” could be installed on the suit at the location specified by the buyer. I did not time the “dive” but it seemed a bounce dive at the time. Another use for a chamber, and risks discounted.” The USN practiced similar events for wannabe pilots up to the mid 90’s as I  recall to determine if the student was “susceptible to the bends.”
Dr. Ed Kay relates that, “We still do (more conservative) dry chamber runs for scuba clubs and others interested in commercial diving at the Divers Institute (DIT).”
Dr. Allen Dekelboum describes his experience doing a dry dive with his course at NOAA. ” We dove 200 feet on air and then on helium. For the air dive, we were all extremely narced, but we were told we had a great time. No one got bent, but I did have a very slight case of niggles on the helium dive, all disappearing very quickly on 100% O2 .”
Other comments include: “It circumnavigates the actual causes of diving deaths, and so it probably does little harm”. (Carl Edmonds, MD). “A clever way to support running a chamber. Trying to experience narcosis in a relatively safe environment isn’t totally a bad idea.” (Ed Golembe, MD)

Some side effects of hyperbaric oxygenation treatment include seizures and lung damage from oxygen toxicity, finger numbness, inflamed middle ear and refractive changes in the lens of the eye.
In a 10-year study of 1,505 patients who received 52,758 2-hour HBO treatments at 2.4 ata once or twice daily (The maximum treatment protocol used for problem wounds around the world), the following side effects were noted:
Inability to equalize middle ear pressure 0.37%
Paranasal sinus blocks 0.09%
Confinement anxiety 0.05%
Oxygen convulsions 0.009% (all ceased after removing hood/masks)
Pulmonary oxygen toxicity 0.00%
Permanent ocular refractive changes 0.00%
Some of the contraindications for hyperbaric oxygenation are listed here. These could also apply to dry diving - but in each instance the person would probably not be certified as ‘fit to dive’ anyway.
1. Asthma - Small airway hyper-reactivity may result in air trapping and pulmonary barotrauma on ascent. A decision to treat such patients should not be undertaken lightly, particularly in light of evidence that the administration of some bronchodilators may increase the incidence of cerebral arterial gas embolism through pulmonary shunts from vasodilation. .
2. Congenital spherocytosis - Such patients have fragile red cells and treatment may result in massive hemolysis
3. Cisplatinum - There is some evidence that this drug retards wound healing when combined with HBO.
4. Disulphiram (Antabuse) - There is evidence to suggest that this drug blocks the production of suproxide dismutase and this may severely effect the body’s defenses against oxygen free radicals. Experimental evidence suggest that a single exposure to HBO is safe but that subsequent treatments may be unwise. Whether or not this would apply to air diving is unknown.
5. Doxorubicin - (Adriamycin). This chemotherapeutic agent becomes increasingly toxic under pressure and animal studies suggest at least a one week break between last dose and first treatment in the chamber.
6. Emphysema with CO2 retention - Caution should be exercised in giving high pressures + concentrations of oxygen to patients who may be existing on the hypoxic drive to ventilation. Such patients may become apneic in the chamber and require IPPV (intermittent positive pressure ventilation). In addition, gas trapping and subsequent lung rupture are associated with bullous disease.
7. High Fevers - High fevers (>38.5degC) tend to lower the seizure threshold due to O2 toxicity and may result in delaying of relatively routine therapy. If patients are to be treated then attempt should be made to lower their core temperature with antipyretics and physical measures. Whether or not this would apply to air diving is unknown.
8. History of middle ear surgery or disorders - These patients may be unable to clear their ears, or risk further injury with vigorous attempts to do so. An ENT consult for possible placement of tubes is usually wise. The risk for a dry dive would not be worth the benefit.
9. History of seizures - HBO therapy may lower the seizure threshold and some workers advocate increasing the baseline medication for such patients. Whether or not this would apply to air diving is unknown.
10. Optic Neuritis - There have been reports in patients with a history of optic neuritis of failing sight and even blindness after HBO therapy. This complaint would seem to be extremely rare but of tragic consequence. Whether or not this would apply to air diving is unknown.
11. Pneumothorax - A pocket of trapped gas in the pleura will decrease in volume on compression and re-expand on surfacing during a cycle of HBO therapy. During oxygen breathing at depth nitrogen will be absorbed from the space and replaced with oxygen. These fluxes of gases and absolute changes in volume may result in further lung damage and or arterial gas embolization. If there is a communication between lung and pneumothorax with a tension component, then a potentially dangerous situation exists as the patient is brought to the surface. As Boyle’s Law predicts, a 1.8 litre pneumothorax at 20 msw is potentially a 6 litre pneumothorax at sea level - certainly a life threatening situation. For this reason it is mandatory to place a chest tube to relieve a pneumothorax before contemplating HBO therapy. Particular care must be taken with patients who give a history of chest trauma or thoracic surgery.  Whether or not this would apply to air diving is unknown.
12. Pregnancy - The fears that either retrolental fibroplasia or closure of the ductuc arteriosus may result in the fetus whose mother undergoes HBO appear to be groundless from considerable Russian experience. However, HHI continues to exercise caution in limiting treatment of pregnant women to emergency situations.
13. Upper Respiratory Tract Infections - These are relative contra-indications due to the difficulty such patients may have in clearing their ears and sinuses. Elective treatment may be best postponed for a few days in such cases.
14. Viral Infections - Many workers in the past have expressed concern that viral infections may be considerably worsened after HBO. There have been no studies to give convincing evidence of this and no reported activation of herpetic lesions associated with HBO.
For more information, go to: www.scuba-doc.com/hbocont.htm.

Ern Campbell, MD
scubadoc Diving Medicine
http://scuba-doc.com/

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Dealing With a Contaminated Wetsuit

Filed under: Interesting Newsscubadoc @ 4:55 pm

In a question on our Scuba Clinic Forum, there is a question about guidelines for the management of the accumulation of contaminants in wetsuits over time. There follows several answers concerning the washing and care of wet suits and basically stating that there needs to be studies to determine the correct way to rid wet suits of contaminants. You might want to vist the thread and post if you have any suggestions about maintaining your gear in polluted water and beaches.

The answer is that basically wet suits cannot be adequately cleaned after contamination.
Here is a great letter from Sean Sheldrake the Deputy Dive Safety Officer, USEPA, Region 10. We have his permission to publish.
“Dear Dr. Campbell,
We here in the Region 10 dive unit very much enjoy your blog and read it with some regularity. We did read some disturbing posts recently regarding “contaminated water diving” with a wetsuit*, and what was more disturbing, the implication that the wetsuit could somehow be cleaned. Other than covering or neutralizing foul odors, removing salts, etc., wetsuits cannot be cleaned. The diver always has a level of dermal exposure using a wetsuit (and by implication ingestion due to the use of an “in the mouth” regulator), and to varying degrees the wetsuit forever carries the contaminants to which it has been exposed. NOAA and EPA have done studies in the 1980’s which well establish the fact that neoprene materials will become impregnated with contaminants, and should be considered contaminated to varying degrees after diving in polluted water. See the excerpt from the Traver study at the link below “Interim protocol for diving operations in contaminated water”:
http://yosemite.epa.gov/r10/oea.nsf/webpage/Dive+Team+Safety
The EPA dive safety manual section on polluted water may also be of interest. We continue to post what polluted water information resources we can to our website, and advocate that public safety and commercial divers should always wear a full face mask, drygloves, and a non-neoprene drysuit like the Viking. Some like Mr. Barsky suggest that hardhat, surface supplied diving is always the way to go for any level of pollution, but when I see commercial divers working for a “low bid” commercial dive contractor in polluted water wearing wetsuits and recreational regulator units, I think a middle ground
can be advocated which gives the diver a modicum of protection (significant decrease in dermal and ingestion pathway exposure) without spending $10k to outfit one diver in the water.
Thank you for your time.
Sean Sheldrake, Deputy Dive Safety Officer USEPA, Region 10 Environmental Cleanup Office
1200 Sixth Avenue Mailstop: ECL-110 Seattle WA 98101-1128 sheldrake.sean@epa.gov Phone:
206/553-1220 / Fax: 206/553-0124 or -0910 http://yosemite.epa.gov/r10/oea.nsf/webpage/dive+team
http://yosemite.epa.gov/r10/cleanup.nsf/sites/ptldharbor

More about diving in polluted water on our web site here: http://www.scuba-doc.com/polwater.html

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BOAT RESCUE

Filed under: Interesting Newsscubadoc @ 11:33 am

There is one simple action that you can take to possibly save the life of a loved one or a good friend! That is to learn how to get an unconscious or weakened, exhausted person back aboard a boat if they have fallen overboard or have had a swimming or scuba accident. This might seem to be a simple thing to do but it can be almost impossible if person is unconscious and you have no one else to help.

Even if you have had rescue courses where you discuss or practice removal from the water, the scenario is often very different from the private boat situation. An unconscious swimmer or diver is a completely dead weight and is unable to help in any way. If it is a diver, you must remember to remove as much of the gear as possible, not wasting time saving the gear. Inflation of the BC is helpful while the person is still in the water and can be helpful in getting a grasp on the unconscious diver. Often the ladder is of no help, either too high or too mobile. Ropes and lines are often spliced or in use with an anchor and are not readily available.  We present here some tips that might help you get a person into a boat so that a timely resuscitation can be performed.

If you are using an inflatable boat, it might seem easy just to pull the swimmer over the side. This just does not happen however, since the person’s legs tend to float up under the boat and can stop the lift dead in it’s tracks. If the boat is underway as in the process of rescuing a swimmer, the forward motion of the boat keeps the legs from catching and assists in rolling the person into the boat. If the boat is anchored, the best method is to face the person away from you or side on so that the legs won’t catch under the inflation tube. An alternative would be to pull the person alongside flat and lift and roll him into the boat.

Small rigid boats, 12-21 feet in length, can pose similar problems with the same suggestions operable. Legs get caught under the hard chine of the boat. This is not a problem with displacement vessels that have a nice curve under the boat, but which have other more difficult rescue problems unless specially equipped with dive or marlin platforms. Small boats may tip when two or more rescuers stand on one side: add to this the weight of the unconscious victim and we may have a problem with all persons in the water. Getting the victim in the boat over the stern, sitting down to keep the center of gravity low, lifting and rolling the victim over the side may work. Another method is to have a seat that can act as a lifting board (see-saw) over the gunwale or transom. The bottom line is that practice of these methods will find a system that works for you.

Larger vessels usually have higher sides but have better stability and usually a larger crew. These boats usually have a rescue system of some sort stowed aboard. Even these systems require practice and knowledge of the workings of the method, learned only by trials. Lifting stretchers, rigging systems using the boom or mast may be elegant but if not practiced or used often can take too long to set up, negating any benefit to the unconscious victim. Remember that it only takes four minutes of anoxia to cause brain damage.

Systems that work best are the netted ropes or canvas and netting with plastic segments to roll the victim into the boat. Larger boats with marlin boards or dive platforms tend to have fewer problems. Larger crews also provide brute strength, good for simply pulling a diver aboard. Even this can be impossible if there is not a person in the water lifting the arms up for grasping by the onboard crew. Even so it becomes much easier if the victim is moving in the direction of the rescuer by bouncing and pulling the victim higher with each bounce.

The take home message is simple: plan and above all practice the rescue beforehand

Beer While Diving?

Filed under: Interesting Newsscubadoc @ 11:02 am

Beer While Diving? There have been recent assertions in scuba magazines, chat rooms and scuba forums that it’s OK to drink beer between dives during a surface interval. Some divers insist on drinking beer before, during and after their dives. Is there any danger in drinking alcoholic beverages and diving? The short answer is that by drinking alcohol before and during diving trips a diver severely endangers not only himself but his buddy! A study by Perrine, Mundt and Weiner found (scuba) diving performances significantly degraded at blood alcohol levels of 40 mg/dl (04%BAC). They also cite a clear increase in the risk of injury at this level which can be reached by a 180 lb. man who ingests two 12 oz. beers in 1 hour on an empty stomach. This very pertinent study once again points out that there is a diminished awareness of cues and reduced inhibitions at relatively low levels of blood alcohol. Their study used well trained divers who were being paid to do their best as their diving performances were being videotaped. Blood Alcohol Concentration (BAC) Research has shown that there is a definite reduction in the ability of the individual to process information, particularly in tasks that require undivided attention for many hours after the blood alcohol level has reached 0.0%. This means that the risk for injury of a hung-over diver is increased significantly, particularly if high BAC levels were reached during the drinking episode. The AMA upper limit of the BAC for driving a vehicle in the US is 0.05%. Surely diving with any alcohol on board would be foolish, considering the alien environment (water) and the complex skills required to follow no deco procedures. Alcohol Impairment All of the following behavioral components required for safe diving are diminished when alcohol is on board or has been on board in the prior 24 hours: Reaction time Visual tracking performance Concentrated attention Ability to process information in divided attention tasks Perception (Judgment) The execution of psychomotor tasks. The individual who has alcohol onboard may not feel impaired or even appear impaired to the observer but definitely is impaired and this is persistent for extended periods of time. The use of alcohol, even in moderate doses, clearly carries a self-destructive aspect of behavior and leads to higher probabilities for serious accidents. Alcohol is a diuretic In addition to these dangers is the definite danger of alcohol-produced dehydration. Dehydration is considered to be one of the prime causes of decompression illness. Alcohol in any form has a direct effect on the kidneys, causing an obligatory loss of body fluids. If your drinking buddy is an intelligent diver, surely he will understand that this is not preaching - a cool beer is appreciated by the author - but by drinking and diving he can turn a safe sport into a nightmare for himself and his family. I’m sure that when he considers that he is also endangering his buddy that he will think twice before drinking alcohol before and while diving. My friend, Dr. Glen Egstrom, PhD has stated the problem succinctly: He made personal review of over 150 studies on the effects of alcohol on performance has resulted in the following observations: 1. Ingestion of even small amounts of alcohol does not improve performance: to the contrary it degrades performance. As Lieber has stated in his study on the effects of small amounts of alcohol, “alcohol can never make you do a thing better, it can only make you less ashamed of your mistakes.” 2. While there are variables that can speed up or delay the onset of the effects of alcohol, they are minor issues which do not overcome the decrements to the central and peripheral nervous system. 3. Alcohol can be cleared from the blood at a predictable rate. Generally on the order of .015% BAC per hour. This does not necessarily mean that the decrements in performance have been completely eliminated in that time. 4. Alcohol is a depressant drug that slows certain body functions by depressing the entire central nervous system. Effects are noticeable after one drink. 5. The effects are mood elevation, mild euphoria, a sense of well being, slight dizziness and some impairment of judgment, self control, inhibitions and memory. 6. Increases in reaction time and decreases in coordination follow the dose/response curve quite well. 7. Alcohol is involved in 50% +/- of all accidents involving persons of drinking age. 8. The deleterious effects of alcohol on performance are consistently underestimated by persons who have been drinking alcohol. 9. Divided attention tasks are found to be affected by alcohol to a greater degree than those tasks with single focus of concentration , i.e. a task such as a headfirst dive into shallow water, with many interrelated decisions necessary to a successful dive, will be impacted to a greater degree than lifting a heavy weight.

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Abandoned Divers, What to do, How to Prevent

Filed under: Interesting Newsscubadoc @ 10:44 am
What if the unthinkable would happen to you? Would you be prepared? here are a few suggestions that just might save your life.
The Boat

* Check out the boat and boat captain before diving
* Ask questions about rescue action plans
* Ask about the history of the motor
* Ask about the credentials of the crew
* Ask about the system for counting heads (Names!)
* Find out if the boat has a functioning radio
o Request to see and hear it function
o Ask who they call for assistance
* Be alert to location of the nearest land

The Dive

* If a drift dive, listen carefully for instructions, stay with the group
* Check for current, tide and wind conditions; imagine yourself out of sight of the boat
* Always start your dive by swimming upcurrent after orienting yourself
* Develop navigational skills. See http://www.scubadiving.com/training/instruction/navigation/

Equipment possibly helpful

* Inflatable Sausage
* Reflector
* Whistle or other noise maker
* Slate
* Line

Hazards of being left behind

* Dehydration and thirst
* Hypothermia
* Severe sunburn and immersion injury
* Marine animal injury
* Drowning

Things to do

* Inflate BC
* Drop weights, preserving belt
* Inflate sausage
* Flash reflector (Someone might see it, even though you can’t see them)
* Blow whistle
* Write time, approximate location and speed of current on your slate
* If you swim, swim diagonally with the current toward any known dry land.
* Stay with others involved. Use a tie up method using empty weight belt or other straps. This gives a larger target for searchers.
* Remember that there will be rescue attempts and searchers.

‘Seven Steps to Survival’Survival at sea depends on the recognition that you are in danger of losing your life. There are commonly described “seven steps” to survival that may make a difference in the outcome of some rather terrible situations. Even an accident fairly close inshore in cold water can quickly lead to hypothermia and drowning. The seven steps to survival are: recognition, inventory, shelter, water, food, signals and play. Of course, flotation is a prerequisite for any survival after only a short time in the water. Other factors come into play, the most important of which is unmeasurable, “the will to live”.

The seven steps to survival include recognizing that you are in peril and realizing that what you are wearing constitutes a form of shelter. Use signals in the form of mirrors, flares, colored objects or waving arms, suits or objects about to attract attention. Finally, “play” comes into action as you have memories, fantasies, prayer, tell jokes and get rid of your anger.

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March 4, 2008

Transient global amnesia after breathing hyperoxic mixtures in otherwise regular dives

Filed under: Interesting Newsscubadoc @ 9:06 am
Here is an article sent to us by Dr. Howard Homler:

Fabio Spignoa, Massimo De Lucchib, Luca Migliazzia and Leonardo Cocitoc, Corresponding Author Contact Information, E-mail The Corresponding Author
aDepartment of Occupational Medicine, University of Genova, Genova, Italy
bUnit of Hyperbaric Therapy, San Martino Hospital, Genova, Italy
cDepartment of Neurosciences, Ophthalmology and Genetics, University of Genova, Genova, Italy
Received 5 June 2007;  revised 24 August 2007;  accepted 27 August 2007.  Available online 24 October 2007.

Abstract

The diagnosis of decompression sickness may be difficult, particularly when patients present with atypical clinical manifestations after dives going on uneventfully and with full adherence to safety parameters. The case reports involve two divers who presented with transient global amnesia (TGA) immediately after surfacing from otherwise regular dives during which they had been breathing hyperoxic mixtures (Nitrox). A wide spectrum of symptoms of neural dysfunction following hyperoxic mixtures have been reported, including cases of memory impairment related to previous generalized convulsions. After a review of the literature, however, we found no previous reports of TGA, which is very unlikely to result from an epileptic mechanism, as an adverse effect of breathing hyperoxic mixtures.

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February 22, 2008

Prisoners endure diver’s training program

Filed under: Interesting Newsscubadoc @ 3:34 pm

There is an article in the Los Angeles Daily News describing a program for training prisoners in diving skills, including diving medicine.

For the entire article see this link:
Prisoners endure diver’s training program

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February 21, 2008

Dysbaric Osteonecrosis in Experienced Dive Masters and Instructors

Filed under: Interesting Newsscubadoc @ 11:34 am

Authors: Cimsit, Maide1; Ilgezdi, Savas1; Cimsit, Cagatay1; Uzun, Gunalp1

Source: Aviation, Space, and Environmental Medicine, Volume 78, Number 12, December , 2007 , pp. 1150-1154(5)

Abstract:
Cimsit M, Ilgezdi S, Cimsit C, Uzun G. Dysbaric osteonecrosis in experienced dive masters and instructors. Aviat Space Environ Med 2007; 78:1150-4.
Introduction: Dysbaric osteonecrosis (DON) is a type of aseptic bone necrosis of long bones such as the humerus, femur, and tibia. It is observed in workers who perform in high-pressure environments.
Methods: There were 58 volunteer divers included in this study who had performed at least 500 dives, were working as a dive master or instructor, had never performed industrial and commercial dives, and did not have a diagnosis of osteonecrosis. Radiological evaluation was performed according to the guidelines suggested by The British Research Council Decompression Sickness Panel. A total of eight X-rays were taken per patient. When suspicious lesions were detected, MRI of the region was performed.
Results: Of the 58 divers, 2 were eliminated because of inadequate X-ray studies. A total of 18 DON lesions were detected in 14 of 56 (25%) divers. Age was the only variable independently associated with the development of DON (P < 0.05).
Discussion: The DON prevalence of 25% in this study is high considering the dive instructors had thorough diving training and strictly practiced the decompression rules. We believe this high prevalence is a result of frequent and sometimes deep dives for many years. Our findings raise the question of whether these divers can be seen as “sports divers” or should be seen as “occupational divers.” If the latter description is approved, dive masters and instructors should be kept under periodic screening for DON lesions just like professional commercial divers to help reduce the morbidity associated with this disease.
Keywords: DON; radiology; screening

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Authors: Klingmann, Christoph1; Gonnermann, Achim1; Dreyhaupt, Jens1; Vent, Julia1; Praetorius, Mark1; Plinkert, Peter K.1

Source: Aviation, Space, and Environmental Medicine, Volume 79, Number 2, February , 2008 , pp. 123-128(6)

Abstract:
Klingmann C, Gonnermann A, Dreyhaupt J, Vent J, Praetorius M, Plinkert PK. Decompression illness reported in a survey of 429 recreational divers. Aviat Space Environ Med 2008; 79:123-8.
Background: The purpose of this study was to investigate the influence of diving experience and diving techniques on the lifetime incidence of decompression illness (DCI).
Methods: Attendants of three diving medical symposia voluntarily answered a questionnaire about their age, gender, medical history, diving experience, diving habits, diving certification levels, and diving associated incidents (cross-sectional survey).
Results: Out of 650 divers, 429 completed the questionnaire. The study population consisted of experienced divers with an average of 670 dives. The majority of the divers were certified diving instructors (43%). There were 37 participants (8.7%) who were classified as technical divers with an average of 1193 logged dives. There was an overall lifetime incidence of DCI of 1 per 5463 dives. The complete study group showed an increased lifetime incidence of DCI with decreased diving experience (1.97-fold to 8.17-fold higher). Of the divers, 27% reported severe DCI with neurological symptoms. The lifetime incidence for severe DCI was 1 in 20,291 dives. Again, lifetime incidence for severe DCI was increased with decreased diving certification level (1.1-fold to 13.7-fold higher). Technical divers showed a DCI lifetime incidence of 1 to 8591 dives compared to the non-technical divers with a lifetime incidence of 1 to 5077 dives (not significant).
Conclusion: In our study population, the lifetime incidence of DCI was increased in divers with less diving experience. If further studies confirm this finding, diving federations should be encouraged to intensify their efforts of educating divers and should limit diving time and depth in inexperienced divers.

Abstract:
Uzun G, Toklu AS, Yildiz S, Sonmez G, Aktaş Ş, Sezer H, Mutlu H, Cimşit M. Dysbaric osteonecrosis screening in Turkish Navy divers. Aviat Space Environ Med 2008; 79:44-6.
Introduction: Dysbaric osteonecrosis (DON) is regarded as an occupational disease for caisson workers, commercial, and military divers. Magnetic resonance imaging (MRI) was suggested for the surveillance of military divers for DON. This study aimed to determine the prevalence of DON in Turkish Navy divers.
Methods: The shoulder, hip, and knee joints of 106 male divers were screened for DON with MRI. A questionnaire was used to obtain information about subjects’ medical history and diving experience.
Results: The mean age of divers was 34.3 ± 5.8 yr. The divers had spent an average of 12.1 ± 6.1 yr at their occupation. The average of total hours of diving was 834 ± 458 h. The maximum diving depth was 53.0 ± 18.4 m (175 ± 61 ft) and the average diving depth was 13.3 ± 8.4 m (44 ± 28 ft). MRI examinations of divers did not reveal bone lesions consistent with osteonecrosis.
Discussion: We concluded that the risk of DON is very low for military divers who strictly obey the decompression rules and who undergo periodic medical examination. The use of MRI for routine screening of military divers is not justified.