In HBO therapy, the patient is placed in a specially designed metal chamber, accompanied by a trained medic. The environmental pressure in the chamber is increased, typically by one to two atmospheres (equivalent to a 10 to 20 metre dive). The patient will then breathe 100% oxygen at the same pressure, using a specially designed facemask or in some cases an oxygen hood. The therapy typically lasts from 1 to 2 hours at full pressure depending on the treating Physicians’ recommendation. During the process of the HBO therapy, the body tissues become saturated with oxygen to a far greater degree (up to 2000%) than they ever could be under normal pressure, thus exposing the patient’s entire body to high levels of oxygen.

HBOT treatments typically include three phases: Compression, Prescribed Time at Pressure (the actual treatment) and Decompression.

Compression: After the doors are closed, one can hear the compressed air being blown into the chamber. The occupants will feel a slight pressure in their ears, just like when flying in an aeroplane or scuba diving. The attendant communicates with the patient and the speed of compression is adjusted to everyone’s comfort level.
Treatment:During the time at the prescribed treatment pressure (or “depth”) the patient will relax and simply breathe 100% oxygen via a facemask or transparent hood. These breathing periods are interrupted by one or more breaks, where the patient can remove the mask, drink something, chat with the other occupants, or simply relax. A medically trained attendant is inside the chamber with the patients at all times. He/she will do periodic medical assessments and continuously monitor the patients’ progress and well-being.
Decompression: When the pressure is slowly reduced to normal surface level again, the occupants might just experience a slight drop in temperature, as the expanding air cools down. Otherwise nothing but a slight crackling sensation in the ears could be felt.