During HBO therapy, a pressurized hyperbaric chamber enables the blood’s plasma, the fluid surrounding the cells, to absorb more oxygen according to Henry’s Law, the physical principle by which liquid absorbs a greater amount of gas in a high-pressure atmosphere. This combination of increased O2 and atmospheric pressure allows the blood to carry greater amounts of O2 to areas of the body that are in need of healing.
A hyperbaric chamber is a steel, aluminum or clear plastic space (monochamber) or room (multichamber) in which air can be compressed to a pressure greater than sea level. Most patients are treated at a pressure equivalent to two or two and a half times normal atmospheric pressure.
Chambers can have portholes or small windows or be made out of a special thick, strong plastic/acrylic shell. They may be furnished with comfortable reclining chairs or stretch out to a flat position so a patient can lie down. In some chambers music or movies can be played during treatments, which are usually provided through a headset or an interior speaker. Whenever the chamber is in use, medical personnel trained in hyperbarics are in constant contact via visual or audio communications.
The monoplace hyperbaric chamber contains either compressed oxygen or air and is built for one person. Oxygen is delivered directly or through a hood or mask. The multiplace chamber will fit between 2 and 30 patients, and oxygen is delivered through a hood or mask but never directly from the atmosphere.
Oxygen at pressure is considered a prescription drug and is prescribed by a physician. At physician-run, freestanding clinics, patients do not generally need a prescription before scheduling an appointment for a consultation with a hyperbaric physician. Some insurance companies do require that another doctor make the referral to the hyperbaric doctor as a condition for reimbursement.4
Typically, a referral can be just a request for a consultation by the HBOT’s medical director. In this case, the referring doctor is then less concerned with liability issues since they are only requesting an opinion from the HBOT physician. The patient is then assuming the risk if they decide to pursue treatment.
At clinics run by non-medical personnel that do not have an active medical director, the owners of the clinic will require a prescription. The owners may determine the specifics of treatment (pressure, duration, number of sessions) but they do need a physician to authorize the treatment.
In most cases it is advised that the patient seek treatment at physician-run facilities where the doctors who give the therapy also write the orders and monitor the dose according to patient response. In the U.S., both freestanding clinics and hospitals provide HBOT. There are many Internet sites that provide a list of HBOT facilities as well as various chat and discussion groups.5
In a non-emergency situation, patients may want to visit the HBOT center, speak with patients who are being treated at the facility, and talk to the staff and doctor. This is especially important when the center is using monoplace or multiplace chambers that are called “hard-shell,” that is, made of steel and acrylic which use higher pressures than the “soft-shell” chambers that are portable, made of inflatable, soft materials, and operate at lower pressures.
For the many “off-label” diagnoses, reimbursement is unpredictable. Very little information on off-label reimbursement for hospital inpatients is available, since few patients are treated for off-label diagnoses in HBOT centers. The whole issue is in flux and therefore confusing.6
The experience of HBOT, often called “diving,” is described as feeling like being in an airplane while it’s ascending. If pain is experienced in the ears or sinuses, the technician or attending physician stops the compression and allows the patient to clear the ears. If the ears cannot be cleared the treatment is discontinued. An antihistamine is used for those with histories of sinus problems.
4 P. G. Harch & V. McCullough, (2007). The oxygen revolution: Hyperbaric oxygen therapy. New York: Hatherleigh Press, 179.