Hyperbaric Oxygen Therapy

Using 100% oxygen while the atmospheric pressure is raised is known as hyperbaric oxygen therapy, or HBOT. The history of HBOT treatment dates back to the 1600s. Henshaw, a British clergyman, built and oversaw the first famous chamber. He constructed a building known as the domicilium, which served as a medical facility for several ailments. Bellows were used to either unpressurize or pressurize the chamber using air. The French surgeon Fontaine carried on the tradition of treating patients under greater pressure when he constructed a pressurized, mobile operating room in 1879. Anesthesia professor Dr. Orville Cunningham oversaw what was referred to as the "Steel Ball Hospital." The building measured 64 feet in circumference and six floors high when it was built in 1928. Three atmospheres of pressure might be reached in the hospital. The hospital was shut down in 1930 because to a dearth of scientific data showing that this kind of care reduced illness. During World War II, it was dismantled for scrap.

The military kept using hyperbaric oxygen for research. Paul Bert's study, which showed how oxygen may be toxic and cause widespread seizures, and J. Lorrain-Smith's work, which showed how oxygen can be hazardous to the lungs, were used to Navy divers. Convulsion time was used to measure and test oxygen exposure durations at various water depths (and, consequently, pressure levels) based on that information.

There might not be nearly enough HBOT therapy centers in the US. Just 43 out of the 361 chambers found across the country were set up to deal with high-acuity patients. HBOT plays a critical role in the treatment of acute carbon monoxide poisoning, arterial gas embolisms, and decompression sickness.

Hemoglobin is saturated when a patient receives 100% oxygen under pressure, however oxygen can dissolve in the plasma and cause the blood to become hyperoxygenated. There are two primary chambers available for systemic oxygen administration to the patient: Type A, multiplace, and Type B, monoplace. Both kinds are useful for treating patients who are ventilated or in critical care, as well as for routine wound care and the majority of dive injuries.

Typically, a nurse or another inside observer monitors the patients and helps with equipment manipulation or crises in multiplace chambers, which treat numerous patients at once (see images below). In a multiplace chamber, patients wear a close-fitting plastic hood or mask that allows them to breathe 100% oxygen. Generally, multiplace chambers can be pressured to a pressure of roughly six atmospheres.

Should an other gas mixture (such as helium or nitrogen) be preferred, the patient alone—not the staff member—may receive the combination through the mask. Ventilators and IV lines are only two examples of the equipment that is brought inside the patient's chamber along with them. Since the worker is not wearing a mask and is inhaling air during the procedure, it is important to keep an eye on how much nitrogen they are consuming because this puts them at risk for issues like decompression sickness (DCS), which is a condition that scuba divers occasionally experience.


One person at a time is compressed in a monoplace chamber, typically when they are reclining (see figure below). Usually, 100% oxygen is employed as the pressurizing gas in the vessel. Masks that offer an alternative breathing gas (like air) are available in certain chambers. The equipment is kept outside the chamber, and staff members provide care for the patient from outside. Only specific ventilation ducts and IV lines can pass through the hull. More recent Duoplace rooms accommodate two persons. They function in a manner akin to a monoplace chamber.

Though they are not regarded as HBOT, there are two more kinds of chambers that are noteworthy.

Topox, also known as topical oxygen, is applied via a tiny oxygen-pressurized chamber that is put over an extremity. Neither the oxygen nor the pressure on the rest of the body is inhaled by the sufferer. Because of this, the majority of HBOT's beneficial effects—which are systemic in nature or happen at a depth that topical oxygen cannot reach—are not available to the patient (see the section below on Hyperbaric Physics and Physiology). The theory behind topox is that oxygen permeates tissue at a depth of 30 to 50 microns. Carbon monoxide (CO) poisoning, arterial gas emboli (AGE), and DCS are not treated with this technique.

The Topox unit's design presents another issue. In order to compress the machine, there needs to be a pressure differential between the machine and the outside atmosphere. The box's cuff needs to wrap extremely snugly around the limb to create a tourniquet-like effect that prevents the extremity from being forced out of the pressured machine. Insurance does not cover Topox, and the journal Diabetes Care does not recommend it for the treatment of foot ulcers.

The portable "mild" hyperbaric chamber is the other kind of chamber. It is possible to pressurize these soft vessels to 1.5–1.7 atmospheres absolute (ATA). The FDA has only authorized them for the management of altitude sickness. Because these chambers are being employed in off-label indications more frequently, their quantity has increased.



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