Some thoughts on scuba diving while taking erectile dysfunction drugs.
‘Viagra, Levitra, and Cialis all belong to a class of drugs called phosphodiesterase (PDE) inhibitors. Taken an hour before sexual activity, these drugs work by enhancing the effects of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow.

While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection as injections do. The recommended dose for Viagra is 50 mg, and the physician may adjust this dose to 100 mg or 25 mg, depending on the patient. The recommended dose for either Levitra or Cialis is 10 mg, and the physician may adjust this dose to 20 mg if 10 mg is insufficient. A lower dose of 5 mg is available for patients who take other medicines or have conditions that may decrease the body’s ability to use the drug. Levitra is also available in a 2.5 mg dose.

None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs such as nitroglycerin for heart problems should not use either drug because the combination can cause a sudden drop in blood pressure. Also, tell your doctor if you take any drugs called alpha-blockers, which are used to treat prostate enlargement or high blood pressure. Your doctor may need to adjust your ED prescription. Taking a PDE inhibitor and an alpha-blocker at the same time (within 4 hours) can cause a sudden drop in blood pressure.’

Side effects include a bluish tinge to the vision in some  – which should not have any untoward effect on divers. Also, reported possible more serious eye problems and increased stroke haven’t panned out in large studies. If your doctor finds you healthy enough to dive, then you should not have any qualms about using the medications before, during and after your diving trip.

An interesting recent finding is that increased levels of nitric oxide seem to reduce the incidence of bubbling during and after a dive. Thus, it would seem that taking daily doses of Cialis would decrease your chances of getting bubble related diving illnesses. See the abstract of a study printed below.

1: Med Sci Sports Exerc. 2006 Aug;38(8):1432-5.

Exogenous nitric oxide and bubble formation in divers.

Duji? Z, Palada I, Valic Z, Duplanci? D, Obad A, Wisløff U, Brubakk AO.

Departments of Physiology, University of Split School of Medicine, Split, Croatia. zdujic@bsb.mefst.hr

PURPOSE: Prevention of bubble formation is a central goal in standard decompression procedures. Previously we have shown that exercise 20-24 h prior to a dive reduces bubble formation and increases survival in rats exposed to a simulated dive. Furthermore, we have demonstrated that nitric oxide (NO) may be involved in this protection; blocking the production of NO increases bubble formation while giving rats a long-lasting NO donor 20 h and immediately prior to a dive reduces bubble formation. This study determined whether a short-lasting NO donor, nitroglycerine, reduced bubble formation after standard dives and decompression in man. METHODS: A total of 16 experienced divers were randomly assigned into two groups. One group performed two dives to 30 m of seawater (msw) for 30 min breathing air, and performed exercise at an intensity corresponding to 30% of maximal oxygen uptake during the bottom time. The second group performed two simulated dives to 18 msw for 80 min breathing air in a hyperbaric chamber, and remained sedentary during the bottom period. The first dive for each diver served as the control dive, whereas the divers received 0.4 mg of nitroglycerine by oral spray 30 min before the second dive. Following the dive, gas bubbles in the pulmonary artery were recorded using ultrasound. RESULTS: The open-water dive resulted in significantly more gas bubbles than the dry dive (0.87 +/- 1.3 vs 0.12 +/- 0.23 bubbles per square centimeter). Nitroglycerine reduced bubble formation significantly in both dives from 0.87 +/- 1.3 to 0.32 +/- 0.7 in the in-water dive and from 0.12 +/- 0.23 to 0.03 +/- 0.03 bubbles per square centimeter in the chamber dive. CONCLUSION: The present study demonstrates that intake of a short-lasting NO donor reduces bubble formation following decompression after different dives.

So – my take on all this is that it really won’t cause any problems, but would possibly be beneficial in addition to it’s wanted sexual activity.

Your attention is directed to an article in the American Journal of Family Practice, printed in full and free. This is written by James Lynch and Fred Bove and provides the latest in thinking about management of Diving problems. There is an excellent reference listing and numerous links in the article. The article is located at http://www.jabfm.org/cgi/content/full/22/4/399#SEC13 .

Helium Speech – An Astronaut Calls the President of the United States

When you take a breath from a helium balloon and speak, your voice rises humorously. What happens when an astronaut does the equivalent and calls the President of the United States?

In 1965, Sealab II replaced Sealab I, 62 meters (200 feet) down on the ocean floor (photo at left). Sealab II was sometimes called the “Tiltin’ Hilton” because of the slope of the site. Teams of “aquanauts” lived and slept inside, dry, breathing air pressurized to that depth. The Sealab project was under command of Dr. George Bond, Captain, U.S. Navy Medical Corps, affectionately called “Papa Topside.”

NASA Astronaut Scott Carpenter (photo right) spent a record 30 days in Sealab II. After spending that much time at that depth, specific protocols of changing the breathing mixture and the pressure are needed to avoid problems from the dissolved gas that was absorbed while breathing the air at SeaLab pressure. Commander Carpenter did that inside a special decompression chamber, while breathing an air mixture containing helium. Yesterday’s post How To Stay Underwater For A Month explains.

Helium changes heat transfer both inside and outside your body, and changes how fast sound can travel. Sound travels faster through helium than through air. That is the “Donald Duck” effect. People who inhale helium from a balloon and speak on the exhale have a distinctive humorous voice change. Funny voice is temporary, lasting only as long as helium is passing the vocal apparatus. (Helium can’t support life. Don’t continuously breathe balloon or other helium source to get a few laughs talking funny.)

I had heard from my Navy friends that an old recording existed of Commander Carpenter trying to phone President Johnson for a formality of congratulations while still inside the recovery chamber breathing the helium mix.

Recently, my colleague Dr. Derrick Pitts, Director of the Fels Planetarium at the Franklin Institute in Philadelphia, and I were talking about space and underwater habitats. He told me that the recording of Commander Carpenter had been found, restored, and was available through NPR National Public Radio.

The description lists the event as 1964, but I think it would have been 1965. It doesn’t matter. Enjoy the recording.

Over this summer, I hope to write you some interesting stories about decompression, scuba, space research, cool people involved, and my work living under the sea. Until then, here are related stories:

• Space Walks
• Indiana Jones Rocket Sled
• Exercise and Medicine Underwater and at High Pressure
• Exercise and Fitness in Decompression Sickness Risk
• How To Stay Underwater For A Month
• Collapsing Astronaut Gives Healthy Reminder
• Altitude Sickness, Viagra, and Bubbles on Flights
• Altitude Sickness on Flights
• Living Under The Sea

The health consequences of the water pollution have not been quantified by careful study but many local health professionals are concerned with infectious and carcinogenic disease potential for patients who are ocean swimmers, lifeguards and divers. Until adequate epidemiologic data is available the recourse would appear to be logically focused upon conservative practices in selecting dive sites and conditions.

This increase in areas of pollution is a worldwide problem and has affected many diving operations. Diving in polluted water requires that certain precautions be taken, and, in some instances, the use of sophisticated equipment and procedures.  Avoiding diving in areas with high potential for pollution, particularly after heavy rains is fundamental in urban or industrialized areas.

Vibrio – 34 species of this family of bacteria are known and cholera and El Tor vibriones are among those known to be pathogenic to man.  Cholera vibriones have recently been found in Santa Monica Bay in California and have raised concerns although it is not known to have produced any disease. Other vibriones may be anaerobic and produce disease states such as purulent otitis, mastoiditis, and pulmonary gangrene.  V. Proteus found in human fecal material is a common cause of diarrheal disease.  V. Vulnificus is found in sea water.

Enterobacteria
Escherichia – found widely in nature, occasionally pathogenic to man, produces carotenoid pigments and can often be recognized by the orangish pus.  E. Coli,. which has some pathogenic strains is often found in fecal material: and can produce urinary tract infection and epidemic diarrheal disease.

Shigella – produces dysentery

Salmonella – 1000 serotypes, ingestion can produce gastroenteritis including food poisoning, typhoid and paratyphoid.

Klebsiella – can produce pneumonia, rhinitis, respiratory infection.

Legionella- causes Legionnaires disease and Potomac fever.  Perhaps inhibited in salt water.

Actinomycetes – causes a “ray fungus” actinomycosis, an infectious disease in man which inflames lymph nodes, develops abscesses, can drain into the mouth causing damage to the peritoneum, liver and lungs.

Pseudomonas- pathogenic to man, “blue pus” formed by some pseudomonas infections. This can lead to a wide variety of infections including wound sepsis, endocarditis, pneumonia and meningitis. It is known to flourish in dark, warm, damp places, i.e., inside hoses, bladder compartments and similar places that are not cleansed after being infiltrated by contaminants.

Viruses – infectious agents which can result in fevers (frequently severe), mononucleosis, and a wide range of disease states.

Parasites – many types with all manner of effects, all bad, can are found in polluted water.

Chemicals -  There are over 15,000 chemical spills in the U.S. waterways each year and many of these are releasing chemicals that are incompatible with man and the equipment that is worn.

It is becoming increasingly important to develop an understanding of the variations in the local conditions to which individuals expose themselves.  Some areas become particularly hazardous following heavy rains, hot weather and windstorms.  Local health authorities can usually be called for advice regarding any tests that have been performed and the results.  They should also be able to identify areas of high concentrations of pollutants that should be avoided.

When diving in areas where pollution is suspected or expected the following issues are worthy of evaluation.

1. The individual diver should consider the need for appropriate vaccinations and inoculations.  Many of the diseases can be avoided if the individual has taken the appropriate “shots”.  A few that appear worthy of consideration:
Hepatitis A and B
Cholera
Polio
Tetanus
Typhoid, Smallpox and Diphtheria

2. Pollution and filth are often associated. If the water contains obvious trash and garbage it is quite probably an unhealthful diving environment and another location should be selected.  If the water looks nasty it probably is nasty!!

3. Many diseases have an incubation period before they exhibit symptoms.  Medical advice is as close as the phone and early diagnosis and treatment can sometimes be improved if the Doctor understands that an individual may.have been submerged in polluted water.

4. Information on chemical spills can be obtained from the Chemical Transportation Emergency Center (1 800 424 9300 US).

5. “When in doubt- Check about”

A basic procedure if one feels they must dive in high risk water involves reducing the exposure of the diver.  NOAA has pioneered a sophisticated SOS (suit over suit) system that will virtually isolate the diver from any contact with the water.  This system is somewhat complex inasmuch as it requires complete system integrity from the times the diver dresses out until the system has been decontaminated following the dive.  Strict procedures are followed to ensure that the divers body does not contact the fluid in which it is immersed.

Previously, many public safety divers wore a  single dry suit and a full face mask during their dives. However, Stephen Barsky now states that “Full-face masks only provide minimal protection and should only be used in environments where the pollutants are known, and do not pose a threat of death or permanent disability. In environments where the pollutants are not known, or where they lead to death or permanent disability, a helmet should be worn connected to a mating dry suit with mating dry gloves. This is considered the standard today.” (See Reference below)

If good seals are involved and the diver is effectively rinsed, scrubbed down and rinsed again prior to breaking any existing seals, the probability of exposure to the pollutants can be minimized.  Special care must be taken to clear hoses and fittings that interface with the life support system.  A failure to rinse bladders and hoses which may later be linked to the divers mouth or lungs could provide a path to the host days after the dive.  The use of snorkels, alternate air sources, oral inflation devices and hose connections should all be given careful attention since the can carry contaminants directly into the mouth.  Positive pressure, “self bailing” breathing systems have definite advantages in that they resist flooding.

Recreational divers maybe well advised to place their regulator in their mouth and their mask over their nose before entering suspect water and keeping it there until they have safely exited the water where they can remove the regulator without needing to replace it.

Polluted water is a fact of our lives.  The degree of pollution can only be mitigated through education and the “upstream” elimination of the sources of the contaminants.  The attitude that careful rinsing of diving gear is a waste of time “cuz its just going to get wet again next time it is used” should probably be replaced with the attitude that one should begin every dive with clean gear.

Utah Bureau of Environmental Chemistry and Toxicology
http://hlunix.hl.state.ut.us/els/chemistry/

Adapted from Glen Egstrom, Ph.D
Medical Seminars, Inc. 1992

Other References:
Colwell, et.al. Microbial Hazards Of
Diving In Polluted Waters, Maryland Sea Grant
Publication UM-SG-TS-82-01.

Diving in High-Risk Environments, 3rd Edition
by Steven M. Barsky
Amazon.com
Paperback – 197 pages 3rd edition (December 15, 1999)
Hammerhead Press; ISBN: 0967430518

Avoid this Disaster

Diving in currents is easily one of the most enjoyable – but can be one of the most dangerous dives that a diver encounters. It is a low energy high speed trip that allows you to see much more of the rapidly passing reef. The flip side of this is that you miss a lot of small life, and the hazards of loss of control and any efforts to work against the currents are high energy and stress producing. Recognizing that a problem exists is the first thing a diver has to face. Divemasters usually are on top of the problem and brief you appropriately.

1). fast moving surface water;

2). which way the boat is facing (depending on whichever is the stronger, the current or the wind);

3). movement of floating material on the water or in the water;

4). movement of divers away from the boat rapidly on entry;

5). bubbles moving away from a diver at an angle underwater;

6). if the plant life and soft coral underwater are laying down.

The contour of the ocean bottom will change currents, often dramatically. A diver can adjust his speed by moving to the bottom, slowing behind coral heads and outcroppings or holding on to permanent objects, all the time presenting the smallest frontal surface area to the current. Because of a “boundary layer” condition, water molecules that are closest to a surface move the slowest due to their nearness to the surface. Other areas of calmness are areas behind obstacles and the sides of walls. Getting close to the bottom and using your finger or dive knife to stabilize you is usually all you need to hold your position.

As the diver moves through the water column he encounters resistance-and this increases by the square of the velocity of the current as it passes over the body. As a diver works against the current along the bottom, a good indication of the amount of work being performed is by monitoring the respiratory rate, this rising exponentially as exertion increases. “Bottom crawling” is a technique that may have to be used when the swimming exertion level rises. This is easily done in rocky areas but can be a real challenge in sandy bottoms-where a good dive knife comes in handy as an anchor.

If conditions exist so that exertion levels continue to rise, it’s better to surface, inflate and wait. Here is where a safety sausage comes in handy. This is an inflatable, long red plastic tube that juts above the water 6-7 ‘ and can be easily seen as much as a half a mile or more. Shining a flashlight in the bottom of the sausage at night provides a long red light that can be seen at a great distance.

Surface floats are other techniques used in diving in currents. A line attached to a float and to a diver give two advantages; the dive group is marked for the boat operator and any tired or nervous divers can hang onto the line and rest. When drifting free without a line, the boat operator relies on visualizing the diver’s bubbles for location; a surface chop can make it difficult for the boat operator to see the divers bubbles,

Strong currents can rip away a mask or snorkel when turning sideways or looking up. Snorkels do better stored in the BC or under a leg strap underwater so as to reduce drag on the mask. Place a little extra tension on mask straps if strong currents are expected.

The dive group should have a clear understanding of exiting and entering the water in conditions of current. Divers should try to let the current work for them by initiating dives into the current on the first part of the dive and planning the return with the current. Float lines are essential for an orderly entry for the divers to hold position for descent and ascent, otherwise divers will be strung out too far apart for a safe dive. Entries should be timed so that there will be no stragglers and the descent be made under control. Exits are also planned so that the float line can be used to pull against the current rather than having to swim against it.

Currents are usually generated by wind and tides or a combination of the two. Predicting what you will encounter generally depends on using information from the local weather service combined with tide information from local dive operators. In certain areas, such as “The Great White Wall” in Fiji and “Blue Corner” in Palau, the currents are almost always due to tidal action and are fairly predictable. One should always go with local experience in making decisions regarding diving into currents.

Surges

Underwater motions occur in areas where swells are forced against a barrier of some sort, such as a beach, wall, rock, or wreck. A surge is a to-and-fro action complicated by indentations such as caves, rocks or large holes in wrecks. Surges can be used to aid in your movement, carrying you forward in one direction where you can stabilize yourself as the surge retreats, and move forward again with the next surge. They are also dangerous since they create huge forces that can carry you into places that you don’t want to go. Divers should remain distant from diver-size holes in wrecks and caves and learn to use surges as a method of aid in movement, either upward to get back into the boat or to move onto a ledge.

WRECKS

Wrecks create special problems with currents. Frequently the boat will anchor on the wreck, playing out enough scope so that divers can easily descend on the line. A tag line is helpful placed between the anchor line and the stern of the boat, facilitating the descent from the dive platform. Divers who lose contact with the line run the risk of being swept away from the wreck and the diveboat, sometimes requiring rescue after coming up predictably exhausted from fighting the current.