Sunday, May 16

Diving Medicine

Accidents can happen and then you should be prepared. Here are a few well known facts regarding diving medicine.


Coral cuts are easy to avoid. Don’t touch anything, be neutrally buoyant and stay on a safe distance from the reef. No matter how we feel after a cut the damage is far greater on the coral than on the diver. A good start is to not wearing gloves. That makes you more careful. Still accidents can happen and if it happen to you it is good to know that even if it seems to be a minor cut pieces of coral, nematocysts or infected slime become embedded in the wound. Infection and inflammation can result.

If you cut yourself on coral you should:

1. Rinse thoroughly with fresh water (not sea water).
2. Clean the wound with generous amount of antiseptic.
3. Dress the wound with antibiotic powder or ointment several times daily.
4. Vaccination (tetanus prophylaxis) may be required if the cut is serious.
5. Oral antibiotics are not usually required unless the inflammation (swelling, redness and pain) of surrounding tissue.
6. It will be necessary to consult a doctor if the wound does not heal after one week, or the wound start to exude pus.


Nose bleeds occur frequently in sinus barotraumas due to the engorgement of blood vessels of the membranes lining the sinuses (cavities in your scull). The injury occurs during the descent when pain is felt around the sinuses. The pain occurs due to the reduction of volume of air space in the occluded sinuses. The mucus lining of the sinus swells and becomes engorged with blood. With further descent, bleeding into the sinus occurs. With ascent the consequent reduction in volume of airspace, blood is forced out of the sinus, resulting in a nose bleed upon surfacing.

If you have a nose bleed you should:

1. Get out of the water.
2. Sit down and tilt your head slightly forward. Not backwards, as it is popularly believed. Tilting backwards will only result in the blood flowing to the back of the throat.
3. Applying pressure over the nose may not help as the source of bleeding is from the sinus wall.
4. The bleeding should stop spontaneously after a few minutes unless the diver has an inherent bleeding disorder. Seek medical attention if the bleeding is still profuse after 15-20 minutes.
5. Avoid diving for the rest of the day and apply either local decongestants (like nasal spray) or take systemic decongestants (like pseudoephedrine).
6. Allow yourself about a week of recovery after an episode of sinus barotrauma. On future dives, slow your rate of descent. Avoid diving if you have a cold or runny nose.


Many divers claim that as soon they get in to the wet suit they feel that they need to go to the bathroom. That probably has a psychologically explanation but there is a physical reason why you feel the same thing during a dive and the name for it is “immersion diuresis”. This is the body’s response to feeling under pressure. So what does that mean?

On land blood tends to pool in legs due to gravity but under water gravity is neutralized. This means that the blood centralizes in the body and new blood volume expands the heart’s chambers which release the chemical ANF. This increases urine output Blood is shifted to your body’s core, and the hypothalamus gland thinks that this means that your total fluid volume is too high and instructs your kidneys to make urine by slowing down the release of anti-diuretic hormone (ADH) increasing fluid output. All this ends up in your bladder filling up, signalling urge to void.

To prevent this you can:

1. Avoid diuretics like coffee before diving.
2. Try to stay warm. One of the body’s responses to cold is to produce urine.
3. Some prescription drugs, like antihistamine, prevent the constriction of the near skin blood vessels which affect the body’s heat conservation mechanism. Alcohol does the same thing even more.
4. Dehydration does not help. It only increases the risk for DCS.

If you need to go you need to go and if you do, your urine won’t be too smelly if you are hydrated enough.


The better developed your sense of balance is the greater the risk of getting seasick.

To prevent seasickness you can:

1. Avoid eating a heavy meal just before the boat ride. Especially not oily food.
2. Get some anti motion sickness medication one to two hours before you go on your trip. There are herbal versions (e.g. ginger candy) on the market.

If you are on the boat starting to feel seasickness you can:

1. Look at the horizon. A stable horizon helps you provide a fixed focal point for your eyes. This visual input will influence your brain to think you are on stable ground. Looking down on deck or close your eyes will only worsen your seasickness. Avoid the galley (ship kitchen) or other “smelly” compartments. Fresh air outside is a much better option.
2. Lying down. The horizontal position will reduce the sensation of motion perceived by the balancing organs in your inner ear. Falling asleep is even better, providing that you haven’t already started throwing up.
3. Get in to the water quickly. Once rigged up get in the water and wait for the others. If you still feel unwell after entering the water, abort the dive. And start on step 1 again.


Middle ear barotraumas occurs when there is an inability to equalize the pressure in the middle ear with the environment. The only communication between the middle ear and the external environment is the Eustachian tube. This tube opens up into the back of your throat.

During descent it can be caused by: poor equalizing techniques, diving while having a cold or flu, or too rapid descent.
During ascent it can be caused by: swelling of middle ear lining due to barotrauma sustained earlier during descent, a rapid ascent, or the effect of an decongestant wearing off at the end of the dive. Being aware of how middle ear barotrauma can occur may help you avoid the problem.

If you feel pain in your ear and a sensation of fullness you may be suffering from middle ear barotrauma. Other symptoms include hearing loss, nausea, giddiness and ear/nose bleed.

If you experience any of these symptoms you should:

1. Abort the dive if you are descending. Or ascend slowly at the end of the dive.
2. Do not attempt to equalize forcefully as this can cause injury in the inner ear.
3. Seek pain relief. Medication like Panadol may help.
4. Do not put anything in your outer ear! It may enter your middle ear if your eardrum is rupted.
5. A decongestant like Sudafed, Actifed or Decolgen (drug containing doefedrin) or Afrin nasal spray (containing topical oxymetazoline) will help to relief the obstruction of the Eutachian tube.
6. Discontinue diving until a diving doctor has seen you. The injury sustained may worsen with further diving and you may introduce bacteria into your middle ear if your eardrum is rupted.


Pulmonary barotrauma is a potentially life threatening c0ndition as bubbles entering the blood stream at the site of lung injury may travel to the brain and lead to unconsciousness. Burst lung is commonly caused by breath holding during ascent, rapid ascent and air trapped in the lungs due to conditions such as asthma, mucus plugs and water inhalation.
Symptoms include: chest pain, difficulty in breathing, coughing, blueness of the lips and tongue, reduced chest movements on affected side and a deviated windpipe. The diver may also give a loud expiratory grunt on surfacing and laps into unconsciousness.

If your buddy or some one in your group shows signs or symptoms for lung over expansion injury you should:

1. Lay the diver flat with the head facing up. Even if he regains consciousness insist that he remains flat.
2. Monitor the divers airway, breathing and pulse rate.
3. Administrate 100% oxygen, or highest percentage available.
4. If the divers heart stops beating, commence cardiopulmonary resuscitation.
5. Arrange for transport to recompression facility. During transport record details of dive, any first aid administrated and the diver’s response to it. This will help the diving physician the severity of the diver’s condition.


Decompression sickness is

If your buddy or some one in your group shows signs or symptoms for Decompression sickness you should:

1. Ensure that the airways are free from any foreign subjects (e.g. dentures, blood clots and food). If necessary use fingers (chopstick fashion) to remove these objects. But be careful not to push the foreign objects further down the airway.
2. Listen to the breathing and look at the rice and fall of the chest during breathing. If the casualty is not breathing it will be necessary to perform rescue breathing two strong puffs with a good seal between the rescuers and the casualty’s lips and pinched nose to prevent the air to escape. Check that the chest is moving, if not, the airway is probably obstructed.
3. If the casualty is breathing normally, provide 100% oxygen. Again, ensure a good seal when placing the mask over mouth.
4. Check the circulation by feeling the pulse. One of the pulses readily felt is the carotid. Run your index and middle fingers from the prominence of the throat sideways and you will be able to feel the carotid pulse. Check for rate and intensity. If pulse is absent, cardiopulmonary resuscitation is required.
5. Place the casualty in a supine position (i.e. flat with head facing up). There is no need to tilt the head down.
6. If the casualty is conscious, give small amounts of fluid to improve the hydration status.
Arrange for early evacuation to recompression facility for treatment.