You’ve had a dive accident, and have been forced to ascend with little regard for safety stops; now, you know you’re in serious trouble. Your entire body is in pain, you feel as though your skin is on fire, and you’re experiencing an unfamiliar and unwelcome sense of vertigo. Luckily, your breathing is still alright for the moment, but you’re being given oxygen as the dive boat speeds back to shore. An ambulance has been called for, and you’re mentally preparing yourself for a visit to the local hospital, where a hyperbaric chamber is waiting to restore your body to health. What to expect?
Hyperbaric Medicine: The Facts
Also known as Hyperbaric Oxygen Therapy, Hyperbaric Medicine is the use of oxygen under higher atmospheric pressure than normal. Treatment takes place inside a chamber inside which both atmospheric pressure and oxygenation can be completely controlled by medical staff outside. This type of treatment has been used for centuries, with the first therapeutic use of pressure having taken place in 1662, when an English clergyman named Nathaniel Henshaw had a therapeutic pressurized room built. He called it the Domicilium; powered by organ bellows with valves that controlled air flow, the sealed room could create conditions both above and below normal air pressure conditions. It was used to treat a variety of ills and was said to improve vitality in healthy people who visited it. Later, after World War One, the United States military tested and developed a new type of Hyperbaric Medicine, which was used to treat early airmen and deep sea divers in much the same way today’s hyperbaric chambers do. Today, hyperbaric oxygen therapy (HBOT) is used to treat various medical conditions including carbon monoxide poisoning, and experimental research is pointing toward its effectiveness in treating cerebral palsy and multiple sclerosis.
Most Hyperbaric Chambers in use within hospital settings are hard chambers, usually made of steel or aluminum, with acrylic windows and entry hatches that can be completely sealed off. In addition, there is normally an airlock which allows medical practitioners to enter and exit without disturbing the air pressure inside the treatment area. In addition, there may be a closed circuit TV to talk to doctors on, or maybe an intercom or walkie-talkie to communicate with. Outside the chamber, there is a control panel manned by medical staff. If you’re very lucky, the chamber might be equipped with a television or other entertainment features, but in most cases, you’ll find yourself facing a fairly boring treatment session.
In some places, soft Monoplace Hyperbaric Chambers are used. The smallest are more portable than traditional hard chambers, and they’re less costly, as well. They consist of a flexible acrylic pressure vessel with a bed inside, which is accessed via a dual zipper opening. Pressure is controlled via a valve, and oxygen is fed to the patient via a mask. The largest, on the other hand, are called Multiplace Hyperbaric Chambers. These chambers look a bit like gigantic aquariums and allow for movement; patients and medical staff alike wear oxygen hoods that look like space helmets. These hoods are transparent and flexible, with a seal around the neck and a hose for oxygen delivery. In some cases tightly fitted oxygen masks are used instead.
What to Expect
Depending on the severity of your DCS and the area in which your accident has taken place, you could find yourself in any of these Hyperbaric Chambers, or in a slightly different model that works the same way. While inside the chamber, you will not be able to use any electronics, nor will you be able to wear a watch, use a pen, or carry anything with batteries. You won’t be able to read a book or a newspaper, nor will you be able to wear anything containing nylon, rayon, or wool. The reason for this is that the highly oxygenated atmosphere greatly increases the risk of fire, so anything that might cause a spark, including a spark resulting from static electricity, cannot be brought into the chamber.
Recompression treatment begins with compression to a pressure equal to that felt at a depth of about sixty feet beneath the surface as well as with administration of pure oxygen. If you were on a deeper dive, then treatment standards may call for greater pressure to begin with. Every twenty minutes or so, you’ll be given an air break to breathe regular room air in order to avoid oxygen sickness; this will vary depending upon the severity of your symptoms and the chamber’s specifications; if you are in a hard chamber, you might never realize that you are breathing normal air from time to time, as you will not need to wear a mask.
The length of treatment will vary depending upon your personal condition; treatment times are based on the US Navy’s standard treatment table. Pressure is gradually decreased during the treatment until ambient pressure is reached. Once your treatment has concluded, you will be re-evaluated and provided with a set of instructions to follow.
If, for some reason, you had to wait for longer than 24 hours to receive treatment, your symptoms may be much less likely to respond. Often, you’ll feel joint soreness for a few hours even after recompression has been completed, and in the event you suffered from severe DCS, you might have lasting neurological effects and you may be required to undergo further treatment.
Depending on the severity of your DCS, you could have to wait for as long as six weeks to dive again, particularly if you suffered any neurological symptoms. In the event you suffered pain only, and were able to undergo treatment quickly, you might be allowed to dive again within anywhere from two to seven days. It’s best to be conservative though; most doctors will tell you not to dive for at least two weeks even if symptoms were mild; in case you have lasting or residual symptoms, including any severe neurological symptoms, you may be told to abstain from diving for the rest of your life.
Once you have suffered from decompression sickness, your likelihood of suffering again in the future increases. The best medicine is to always plan your dives, stick with your plan, and seek treatment if you even suspect that you might be suffering from DCS. Taking these precautions and never taking chances can help you to stay fit for a lifetime of enjoyable diving.