Divers Alert Network provides a rare opportunity to learn some very specialist medicine. And that's at the same time as getting in your own wetsuit, says Clare Spooner

Very few places in the world actively pursue diving medicine research, especially outside the military, due to funding difficulties. Divers Alert Network (DAN), an American based organisation, does, and I spent my summer on an internship with them.

Based at Duke University, North Carolina, DAN is also involved in hyperbaric medicine research at the Duke Center for Hyperbaric Medicine and Environmental Physiology. This is for both recreational divers and research for NASA and the military. The facilities include an impressive chamber complex at the hospital, which is used for research and hyperbaric oxygen therapy for patients. The centre's research aims to make recreational diving safer for all by determining the risk factors involved.

DAN provides 24 hour emergency help for divers in the United States and the Caribbean to deal with diving medical problems, offering help and advice in finding the hospitals with the appropriate treatment facilities.

Research

Decompression sickness, also known as the bends, occurs when inert gases (usually nitrogen) escape as "bubbles" into tissues due to a decrease in the ambient pressure--for example, on ascent after a dive. Although there are decompression tables advising dive time and ascent time, it is still possible to experience decompression sickness even if these are followed.

DAN is currently performing a research project called Project Dive Exploration, and I collected data for this over the summer. This is an observational study where recreational divers are recruited and their medical health is followed over the course of their dive trip. They are asked to complete a personal history form including information on their medical history, dive with a computer to capture their depth and time underwater, and report any symptoms. The information is then entered into a computer and sent back to DAN for analysis. The aim of their research is to determine any risk factors associated with decompression sickness and how to make diving safer.

To begin with I spent a week at DAN headquarters in North Carolina learning about the project and more about diving medicine. This included sitting in with the DAN medics on call and visiting the recompression chamber facilities. After that I collected data at the Beaches Resort on the Turks and Caicos islands. This great location has brilliant diving and, therefore, a large number of divers, some of whom took part in the study.

There were two cases of decompression sickness at our dive centre during my time there. To relieve the symptoms divers have to be recompressed by completing a "dry dive" in a recompression chamber.

It is rare for the smaller islands of the Caribbean to have a recompression chamber, and it is often not possible to perform the crucial treatment early enough for it to be effective.

During recompression the patient breathes 100% oxygen at "depth" to try to eliminate bubbles and reoxygenate the tissue so that normal function may be restored.

There is a small risk that while breathing the oxygen the patient may have a fit; therefore, a healthy person (a "tender") accompanies the patient into the chamber, and I was assigned this task. This was an amazing experience.

Expenses

There are about five internships available every year, and these are normally open to any divers with a scientific background. They usually take place in the summer, although internships are possible at other times of the year. The internships are funded through a private organisation; hence interns have to spend little of their own money.

Applications for future internships should be made to Donna Uguccioni (duguccioni@dan.duke.edu), research coordinator, and further information can be obtained at www.diversalertnetwork.org and www.daneurope.org