HBOT Glossary of Terms

A | B | C | D | E | H | I | M | O | P | T

A

Aeroembolism — Obsolete term for altitude decompression sickness; also used to mean gas embolism.

Aerobic — Requiring air or free oxygen in order to live.

Air — 78% nitrogen, 21% oxygen, 1% carbon dioxide and all other gases.

Ambient — Pertaining to the surrounding environment.

Anaerobic — The ability to grow or thrive in the absence of molecular oxygen.

Angiogenesis — The development of blood vessels. Angiogenesis is a major benefit of HBO therapy.

Ascent — Movement in the direction of reduced pressure, whether simulated or due to actual elevation in water or air.

Atmospheres absolute — The sum of barometric and hydrostatic pressures. This is the most commonly used measurement when dealing with HBO therapy. The abbreviation is ATA.

Atmospheric pressure — The amount of pressure exerted by the weight of the air in our every day environment. At sea level the pressure of the atmosphere is 14.7 pounds per square inch.

B

Baromedicine — The area of medicine related to physiological processes that occur either from pressure changes or changes in the concentration of inhaled gases.

Barotrauma — The mechanical damage to the tissues caused by unequal pressures.

Bends — An imprecise term denoting any form of Caisson disease or decompression sickness. It is sometimes a fatal disorder that is marked by neuralgic pains (severe pain along a nerve) and paralysis, and dyspnea (difficult breathing); that is caused by the release of gas bubbles in tissue upon too rapid decrease in pressure after a stay in a compressed environment.

Bottom time — The amount of time from getting in the water at the start of a dive until the beginning of the ascent.

C

Chamber — A vessel designed to withstand differential pressures.

• Double-lock — A chamber with two compartments that can be pressurized independently.
• Hyperbaric — A chamber designed to withstand high internal pressures; used in hyperbaric experimentation, diving simulations, and medical treatment.
• Monoplace — A portable one-person hyperbaric chamber used for therapy in a hospital or clinical setting, and for transport.
• Multiplace — A pressure chamber designed to be used by more than one person at a time.
• Single-lock — A pressure chamber with only one pressurizable compartment.
  Decompression sickness — A condition caused by too rapid a reduction in pressure, and having a variety of signs and symptoms. Synonymous with the bends, Caisson disease, or compressed air illness. The abbreviation is DCS.

D

Decompression — In diving, that phase in which the individual is ascending in the water, or in a chamber when the pressure is being lowered.

E

Embolism — Air or gas bubbles in the arterial (artery: a vessel conveying blood from the heart) system caused by gas or air passing into the pulmonary (lung) veins after rupture of the alveoli (air cells of the lung).

H

HBO — Common abbreviation for hyperbaric oxygen. HBO is the use of increased oxygen concentrations under greater than normal atmospheric pressure.

Hydrostatic — Relating to the pressure that liquids exert.

Hyperbaric oxygenation — Also known as hyperbaric oxygen therapy. The use of an oxygen breathing mixture where the ambient pressure is greater than 1 atmosphere. This is abbreviated as HBO or HBO2.

Hyperbaric — Pertaining to pressure greater than one atmosphere.

Hyperbaric pressure — Pressures greater than atmospheric pressure.

Hyperoxia — An excess of oxygen in the body tissues produced by breathing a mixture in which the inspired (inhaled) oxygen pressure is greater than its partial pressure in air.

Hypoxia — Oxygen deficiency.

I

Ischemia — Local reduction of blood supply due to obstruction of inflow of arterial blood.

M

Microaerophilic — Requiring free oxygen for growth, but thriving best when the oxygen is less than the amounts in the atmosphere.

Monoplace chamber — A HBO chamber designed to hold one person, usually at a maximum pressure of 3 ATA.

Multiplace chamber — A HBO chamber designed to hold two or more persons, usually with pressures of up to 6 ATA.

O

Osteomyelitis — Inflammation of the marrow of the bone.

Osteonecrosis — The process of bone cells dying in mass.

• Dysbaric — Changes in structure of bone in which the relative density of the affected bone is increased by sclerosis (hardening). Observed changes are the result of a healing process following insult (trauma). Found in caisson workers and more recently in divers, and probably due to inadequate decompression. Synonymous with aseptic bone necrosis and avascular bone necrosis.
• Juxta-articular — Osteonecrosis occurring near the joint articulation, usually hip or shoulder. May lead to collapse of the joint, together with pain and dysfunction.
• Medullary — Osteonecrosis occurring in the shaft of the bone, usually symptomless and detected by x-ray.

Otitis — Inflammation of the ear, which may be marked by pain, fever, abnormalities of hearing, tinnitus (ringing in one or both ears), and vertigo (dizziness); a very common problem in diving.

Oxygen poisoning — Deleterious (harmful) effects caused by breathing high partial pressures of oxygen. Prolonged exposure can result in effects which become progressively more severe as the inspired partial pressure and/or the duration of exposure increases. Depending on level and length of exposure, may cause lung damage, involvement of the central nervous system causing convulsions, or early death.

Oxygen toxicity — Physical impairment that results from breathing pure oxygen for prolonged periods of time; the time to achieve toxicity is shortened as the pressure in the surrounding environment increases.

P

Pressure:

• Absolute — The sum of all pressures acting on an object; in diving, the sum of the atmospheric (air) pressure and the hydrostatic (water) pressure acting on a submerged object.
• Ambient — The absolute pressure surrounding an object.
• Atmospheric — Pressure exerted by the earth's atmosphere, which varies with altitude above sea level. At sea level atmospheric pressure is equal to 760 mmHg or 1.03 kg/square centimeter, or 14.7 pounds per square inch.
• Hydrostatic — The pressure of a column of water acting upon a body immersed in the water, equal in all directions at a specific depth.

Pressurize — To increase the internal pressure of a closed vessel.

T

Treatment Depth — The depth or pressure to which a patient is compressed for treatment.