Monday, 1 January 2007

An article on the Hyperbaric Chamber


Diving and Diabetes

The hyperbaric chamber of the Cayman Islands:

I think it’s fair to say that most people do not what a hyperbaric chamber is, or what it does. Not to mention that it is attached to the hospital, as much a part of treatment as the A&E or the Psychiatric Ward. Perhaps most divers have not come across these either, thank goodness.

It sounds like scientific jargon so it must be complicated and for only the elite to know about, unless of course you have a relative who has diabetes, and then, it becomes as important to them as scuba divers. So how come? What is a hyperbaric chamber and what on Earth has diabetes and decompression sickness got to do with it?

I want to start off by saying; I am no expert on either subject, and I am certainly not a brain surgeon. However, I am a diver and an educator with a penchant for writing. I want to expose to you a world that you may not be familiar with and in doing so I hope that you will understand more of what happens in our chamber on the Cayman Island.

I was initially shown the chamber by a work friend, and when I found out that there was a course, to learn to how run the chamber by some diving friends of mine, I wanted to get involved. The first evening of the course 14 people of all genres, all filed into a very small room filled only by a cylindrical gray metal tube about 60cm in diameter, with lots of gauges and valves. You can imagine how intimidated we all where, and it was not just the valves and gauges, it was the 8 or so pipes that joined these and ran from the steel, foreboding cylinder, up to the ceiling, turned a right angle and disappeared into another room.

The room the cylinder was housed in, is part of the hospital, a cold light blue room, austere, and sterile looking despite the smell of freshly brewed coffee which did little to detract claustrophobic minds from entering the chamber and closing the door. The feeling of been trapped inside what can only be described as a glorified pressure cooker can be too much for those with imaginations, so those that that had them, left after one look. It is human nature to be claustrophobic to a certain extent, so perhaps those that stay are not quite right in the head, for sure we are a weird bunch of people, in a nice way!

We were down to 12 when the training began. A brief overview of the course and then a summary of decompression sickness, the signs and the symptoms, interspersed with anecdotes from the lecturer, some were humorous, like trying to squeeze a 300 lb tourist from the cruise ship, having dived, unfit and dehydrated from his holiday. into a 60cm diameter tube for treatment. The treatment was successful; the patient recovered fully, but the human condition never goes away. Others where the treatment was not successful and the patient became a quadriplegic. We all push our limits, I think, one way or another. We would not be alive else right?

Most of the time divers come in with less severe, however, nevertheless upsetting symptoms; a skin rash on the tummy, and a general feeling of malaise. Numbness or aches in the joints, nausea or pins and needles after a dive, sometimes 48 hours after when the diver (usually on holiday) can no longer stand the discomfort, either the alcohol has wore off or the diver has taken a day off from diving and hence not realized that there has been an insult to the body.

Many of the symptoms can be treated by putting the patient into the chamber and pumping air into the chamber, thus compressing it, which is physiologically the same as taking the patient down to 60ft or 45ft in the case of diabetes. What does this do?

If a diver comes up too fast or is unfit, dehydrated, poor dive profile, there are many reasons why and how a diver can experience decompression sickness, and it is by no means an exact science, however, the principle is the same. Imagine screwing the top off a fizzy drink, all the bubbles of carbon dioxide rise to the top right, and they also get bigger. This is Boyles Law, the more pressure you put onto a gas the smaller the volume becomes, in other words, the deeper you go, the smaller the air bubbles become in your lungs. This is usually fine, your body absorbs the excess Nitrogen (from air, air is a mixture of oxygen, nitrogen and other gases) as you ascend from your dive slowly, however, sometimes things go wrong and the bubbles of Nitrogen get stuck in the tissues, your bodies immune system does not like this and begins to fight this insult. This is where all the pain comes from. The main areas that are affected are the joints and the nervous system, where there is little circulation of oxygen, which helps to heal these tissues, which release and absorb the gases slower to other tissues in the body. Bringing the patient back down to a depth of 60ft and giving them oxygen to breath, decreases the size of the bubble, giving almost immediate relief, and oxygen promotes healing of the tissues surrounding the insult. Sometimes 1 treatment will do, but other divers may need 3 or 4 before their body fully recovers, and tragically, some divers never recover fully.

Back to training the team, it takes 5 hours to treat a patient for DCS the system here requires a team of 15 people, a senior operator (they make the coffee) as well as all the important decisions, liaise with doctor and the rest of the team. There is then the outside operator who “drives” the chamber controlling the decent and ascent of the patient and the attendant. Making sure they come up slowly and descend slowly in addition to timing oxygen and air breaks that the patient must do if they are to heal. Lastly (but by no means least) there is the inside attendant who goes into the chamber with the patient and makes sure the patient is comfortable, and as relaxed as they can be. The attendant also monitors the efficacy of the treatment and informs the outside team of any team of any improvements or complications that may arise. All of the team have had to attend a course in CPR and First Aid, in addition to running the hyperbaric chamber and many if not all are enthusiastic and experienced divers willing to give up their time to put something back into the sport, and to raise their own awareness and hopefully make them better divers.

As a result, 12 of us spent three weeks of theory, re learning the gas laws and diving physiology. In addition to understanding what the gauges show and what the valves allow in and out. We followed the pipe work, switched air on and off. We were deafened by compressed air generators and learnt how to man handle our fellow trainees into and out of the chamber. There was some role modeling, we acted as a grumpy patient, in denial or not understanding what has happened to them. The grumpy model went well for the retirees, it came easily as they were roughly transferred from stretcher to treatment bed !

The course was great fun, nurses, teachers, lawyers , diving instructors and retirees attended. This meant many diving stories being told over coffee and water both inside and outside the chamber whilst doing practical sessions after the lectures. Some of the younger students struggled to make the 10am start on Saturdays, it reminded me of being back in university, hungover, tired, wanting only to get the handout, sign that we had attended the lecture (for about 5 mins) and retire to bed. The mind of the latter, still being at Hammerheads or at Sunset House after a night of partying.

So what has this got to do with diabetes? Well the hyperbaric chamber also helps patients , not just diabetics, but any one who has circulation problems which may require additional oxygen to promote the healing process. Diabetics fall into this category. Oxygen, when breathed in at higher pressure, is pushed into the cells that need or promote the healing process. Thus, whereas a toe or foot may need to be amputated, with treatment some of the circulation and hence healing can be brought back thus saving the limb, and improving the morale and quality of life of the patient.

The use of hyperbaric chambers is becoming more and more widespread both in the medical and the sporting community world wide. I think we are lucky a) to have one in the first place and b) one of the best run and staffed chambers in the Caribbean. We also happen to be one of the busiest!
I hope you have enjoyed the tour and that we don’t see you in the near future.

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