When a patient is given 100% oxygen under pressure, hemoglobin is saturated, but the blood can be hyperoxygenated by dissolving oxygen within the plasma. The patient can be administered systemic oxygen via 2 basic chambers:
Type A, multiplace; and
Type B, monoplace.
Both types can be used for routine wound care, treatment of most dive injuries, and treatment of patients who are ventilated or in critical care.
Multiplace chamber
Multiplace Hyperbaric Oxygen chamber treat multiple patients at the same time, generally with a nurse or another inside observer who monitors the patients and assists with equipment manipulation or emergencies. Patients in a multiplace chamber breathe 100% oxygen via a mask or close-fitting plastic hood. Multiplace chambers can usually be pressurized to the equivalent of about 6 atmospheres of pressure.
If a different mixture of gas (nitrogen or helium mixture) is desired, the mixture can be given, via the mask, to only the patient, not the employee. All equipment used with patients, such as ventilators and intravenous lines, is put into the chamber with the patient. Since the employee is breathing air during the treatment (not using a mask), his or her nitrogen intake must be monitored, as this presents a risk for problems similar to those sometimes developed by scuba divers (eg, decompression sickness [DCS]).
Monoplace chamber
A Monoplace Hyperbaric Oxygen chamber compresses one person at a time, usually in a reclining position. The gas used to pressurize the vessel is usually 100% oxygen. Some chambers have masks available to provide an alternate breathing gas (such as air). Employees tend to the patient from outside of the chamber and equipment remains outside the chamber; only certain intravenous lines and ventilation ducts penetrate through the hull. Newer Duoplace chambers can hold 2 people; their operation is similar to that of a monoplace chamber. These are also referred to as personal hyperbaric oxygenchambers.