As open water divers, you learn about one of the biggest risks of scuba diving – Decompression Sickness (DCS). Sometimes called ‘the Bends’, ‘Divers Disease’ or ‘Caisson Disease’, DCS like we’ve seen in our earlier post Decompression Sickness: All About Scuba Diving & The Bends, is caused as the nitrogen absorbed from breathing compressed air underwater remains in the body’s fatty tissues and blood because of the ambient water pressure. Many divers refer to a hyperbaric chamber as a recompression or decompression chamber, although they technically used differently.
When the pressure around the diver decreases (i.e on ascent) the nitrogen starts coming out of the tissues back into the blood stream. However, if you reduce the pressure too quickly, the nitrogen starts forming bubbles in the tissues and bloodstream rather than through exhalation, causing Decompression Sickness/ Decompression Illness.
For treatment, it’s crucial to administer 100% oxygen to the patient and transfer them the nearest hyperbaric chamber or recompression facility for immediate medical attention. But how exactly does the hyperbaric chamber – also known as recompression chamber, decompression chamber or even diving chamber – work for decompression sickness?
A hyperbaric chamber is a container big enough to hold people while also holding gases at a specific pressure. In this case 100% oxygen is delivered and the internal pressure of the chamber is increased.
The main pressure chamber connects using separate airlock chambers with hatches to allow patients entry and exit. The airlocks are independently pressurized to not compromise the pressure in the main chamber. An intercom or walkie-talkies are available for communicating with anyone in the chamber.
How Does Hyperbaric Oxygen Therapy Help for Decompression Sickness?
The therapeutic principle behind hyperbaric oxygen therapy lies in its ability to drastically increase partial pressure of oxygen in the tissues of the body. In other words, cells repair themselves more efficiently when exposed to a higher oxygen content via the blood. Although the hyberbaric chamber itself is the same in most cases, it is used in different ways. That said, there are two ways that this treatment can help when it comes to scuba diving:-
- Decompression Chamber: A hyperbaric chamber used by surface-supplied (typically commercial) divers to make their decompression stops.
- Recompression Chamber: A hyperbaric chamber used to treat or prevent patients suffering from decompression sickness.
The purpose a decompression hyperbaric chamber is to allow surface-supplied gas divers to complete their decompression stops in a chamber rather than underwater.
For this purpose, decompression chambers can be submersible in the water. For a submersible chamber though, the hatch opens into a moon pool chamber. Then its internal pressure must first be equalized to that of the moon pool chamber before opening the hatch. More commonly, the hatch opens into an underwater airlock similar to those used in submarines and underwater living habitats. In this case the main chamber’s pressure stays constant, while it is the airlock pressure which shifts.
However, non submersible decompression chambers are more common. The diver surfaces and immediately enters the decompression chamber to complete the time they would have normally spent underwater decompressing. This reduces the risks for divers diving in cold waters or in risky underwater conditions. Not to forget, this method of decompressing is mostly used in the case of commercial diving, which involves divers working for hours underwater at depths far beyond traditional recreational diving. Because of which they also spends hours (sometimes as long as 18 hours) for the decompression process.
Click here to continue reading part 2 of this post (How a Recompression Chamber helps divers suffering from DCS)