Alert Diver Article
Taking It All the Way - First Aid Care Is Just the First Step
November/December 2008 Issue
By: Eric Douglas

No diver wants to think about being bent. We just don't like to hear those words. Inevitably, on hearing that a diver is bent, some people will conclude the diver made a mistake. I recently read an online comment from one diver questioning a dive instructor's professionalism because he had been bent.

Many times divers make mistakes and get in trouble; many more times divers make mistakes and get lucky. Those in the latter group have no symptoms and walk away from a poorly planned or poorly executed dive with no problems whatsoever.

On the other hand, there are times when divers do everything within the prescribed limits, take every precaution, plan for every contingency and still have problems. How does this happen?

First, we need to recognize that there is an element of chance -- and some risk - in diving. By planning, training and taking deliberate actions, we can control for those risks and increase our safety margins. But the unique physiology of each diver (and even how that physiology changes daily) dictates our body's responses to diving.

As divers go deeper, stay longer, use specialized techniques and make planned decompression dives, or as we go farther in search of pristine environments and memorable experiences, we are more likely to confront troublesome events. As we get farther from home, even on relatively simple dives, we need to be prepared to handle these situations on our own since professional help is also more remote.

How do you get bent?

In the accompanying case study, the diver was within his limits and even took precautions: decompression stops and gas switches that are designed to help his body offgas accumulated nitrogen faster. Upon surfacing, however, he acknowledged he had symptoms of decompression illness. By doing this, he was able to quickly receive oxygen first aid, a move DAN always recommends when signs of decompression illness are present.

When we dive, normally gaseous nitrogen in our bodies compresses and more is dissolved in tissues. As we ascend, DCI can occur as nitrogen bubbles come out of solution and, in some cases, lodge in the body, blocking off blood flow to tissues. As the tissues downstream from the bubbles are deprived of an oxygen supply, they experience trauma, and our body lets us know there is a problem in a specific area.

Oxygen provides relief

Often injured divers get relief very quickly from their symptoms when they begin breathing 100 percent oxygen. The increased oxygen concentrations in the lungs (i.e.,  approaching 100 percent compared to the 21 percent we breathe in normal air) help to oxygenate those tissues that aren't getting oxygen through the usual processes. Oxygen first aid can also reduce tissue swelling (edema) and keep further problems from arising.

There is another important reason - secondary to the pain - for oxygen use first: Oxygen helps the body remove nitrogen. In the nondiving medical world, patients receive oxygen when they are having trouble breathing or when the oxygen concentration in their bodies is inadequate. For divers, oxygen first aid is a little different. Most of the time injured divers are breathing adequately and have adequate circulation and normal concentrations of oxygen throughout their bodies.

By raising the concentration of inspired (breathed) oxygen to as close to 100 percent as possible, the pressure gradient between the oxygen in the lungs and the nitrogen in the bloodstream and the body tissues is raised. The body attempts to find equilibrium between these two gases and will pull more oxygen from the lungs into the body while removing nitrogen from the body more quickly. This is commonly referred to as the "oxygen window."

In this particular case, the diver received oxygen first aid for 30 minutes, and part of his symptoms resolved. Thinking he was cured, he discontinued the oxygen. And his symptoms recurred.

You still need further treatment

Ultimately, the lesson to be learned from this is that oxygen first aid is first aid treatment. But you need more. You could compare it to stopping the bleeding in a trauma situation: You put direct pressure on a wound and bandage it, but you would still go to the doctor and get stitches and probably medications to prevent infection. Divers often receive oxygen first aid and then do not go to a medical facility for evaluation for what is truly the only definitive treatment for a diving emergency: recompression therapy in a hyperbaric facility.

If you have been diving recently -- in the last 24 hours - and feel you have symptoms of DCI, you should begin oxygen first aid, call DAN for advice and get to the closest medical facility for evaluation and referral to a hyperbaric unit. By calling DAN, the medical staff will work with local physicians to help them understand the unique nature of dive accidents and how to deal with them.

There's no stigma to getting DCI. You're better off being careful than delaying treatment. Remember, first aid is just the first step to recovery from a dive injury.

© Alert Diver November / December 2008