From Diving to Diagnosis

HBOT goes back to seventeenth century medicine when it was called hyperbaric air therapy. The first known report of using increased pressure for therapeutic reasons dates back to the 1660s. People would notice that they felt different in higher elevations, such as in the mountains, than they did in lower elevations, like coastal regions. Even though the discovery of oxygen wouldn’t occur until a century later, physiologists would use hyperbaric air – as opposed to hyperbaric oxygen – to treat some conditions.

In 1662 a British clergyman named Henshaw first utilized the pressurization of gas to treat medical disorders.  He compressed air into a sealed chamber he called a “Domicillium.”  Although no evidence was produced and the scientific method was far from followed, Henshaw believed that a wide array of acute disorders could benefit from experiencing increased pressure.13

Oxygen was discovered in 1772 by a Swedish-German chemist named Carl Wilhelm Scheele. However, the findings were not mainstream until English chemist Joseph Priestly published his findings two years later and it wasn’t until 1775 that French chemist Antoine Lavoisier recognized oxygen as an element and officially named it oxygen  – a Greek word for “acid-former.” 14

In the mid-19th century it was general knowledge that low pressures experienced at high altitudes, like those reached in a hot air balloon, caused severe illness and even death.  This observation led to the development of the theory that an increase in pressure, like what could be experienced in a hyperbaric chamber, could increase health and treat disease.  An increase in compressed air therapy followed in France and “air baths” became popular in spas throughout Europe and were compared to the act of “taking in the waters” to treat various conditions.15

Dr. V.T. Junod directed the construction of the first hyperbaric tank at a French iron shop in 1834. Junod’s tank was a copper sphere five feet in diameter with view ports and compressed air fittings.  It was the center of attraction for many patients.  Junod reported amazing recoveries from a variety of patients with a range of ailments.  His chamber was duplicated and distributed throughout Europe even though it was never clear as to the exact physiology behind its working. Prescriptions varied from region to region, condition to condition, doctor to doctor.16 Over the next 40 years enthusiasm for the treatment spread and people came from all over America to try the treatments.  The first North American hyperbaric chamber was not built until 1860 in Canada.17

Early French hyperbaric assisted surgery demonstrated that patients recovered with fewer complications and this interested the European medical profession.  Dr. John S. Haldane studied the effects of compressed oxygen and taught at the University of Dundee in the early 1900s. Haldane developed the first diving tables for the Royal Navy, and he is called the “father of oxygen therapy.”

In the middle of the 19th century, the use of hyperbaric air treatments grew exponentially in France. In 1876 Fontaine had a mobile operating theater used for 27 different operations.  Fontaine noted that patients were not as cyanotic after the use of nitrous oxide as a sedative during surgery.  He also noted that hernias were much easier to reduce in an increased pressure environment.

Even with all of the facilities being opened and used in the United States and Europe, it was not until 1878 that Paul Bert, now considered to be the “father of pressure physiology,” discovered the potentially toxic effect of hyperbaric oxygen. His studies showed the potentially harmful effects oxygen could have on the body if it were inhaled at a concentration of more than 60%. He then recommended the use of normobaric, not hyperbaric, oxygen for the treatment of decompression sickness.18

Several years later in 1937 Behnke and Shaw, cognizant of Bert’s findings that hyperbaric air can cure most cases of decompression sickness, were the first to attempt replacing the air with oxygen. This led the naval doctors to become the first to use an application of nitrogen/oxygen mixtures to aid the recovery time of decompression illness.  Their research and discovery process continued when they started to develop exposure limits, defined as the highest amount of oxygen one can sustain for the longest period of time without causing irreversible damage to the nervous system or oxygen sickness. Their research has become the standard in treating divers with decompression illness in modern times.19

HBOT didn’t seem to gain any real credibility in the medical community until the 1950s when Professor Boerema of Amsterdam published an article titled “Life Without Blood.” The article detailed a famous experiment with pigs where the blood was replaced with a saline solution while they were in a hyperbaric chamber.  The astonishing results of the experiment “prompted renewed interest in the use of HBOT for surgery and especially pediatric heart surgery for blue babies.”   In the 1960s several large clinical chambers were constructed to support surgical operations.

Dr. Orval Cunningham noticed during the flu epidemic of 1918 that there was a higher rate of influenza-related deaths in people at higher elevations than those who lived closer to sea level. Research spawned from this observation concluded that profound cyanosis was a common symptom in advanced cases of the flu and could be treated with HBOT. Since a decreased oxygen concentration adversely affected the lungs and left them open to viral attack, Cunningham simply exposed the ill to an increased oxygen count. He treated several cases of influenza this way, as well as treating cases of syphilis in the 1920s.

The largest facility, however, was built in 1927 in Cleveland, Ohio, USA by Dr. Orval Cunningham.  Cunningham’s chamber was 6 stories high and had 72 rooms.  The facility exposed Cunningham to a lot of press and publicity, so much that the American Medical Association put him under investigation and found that the doctor had made very little effort in documenting or defending his choice of treatments.

In the end, the AMA forced Cunningham to close his clinic because they felt he was economically motivated.  The center was dismantled for scrap metal in the war effort in 1937. This brought a temporary end to the era of using hyperbaric air therapy to assist with medical disorders.

It wasn’t until the 1960s that hyperbaric chambers became a common addition to major hospitals. The initial studies of patients being irradiated while in a hyperbaric chamber led doctors to discover that HBOT was a powerful radiation sensitizer.  Oncologists used HBOT to make significant advances in their clinical trials.  Meanwhile, doctors were using it as a part of their standard practice.  Experimental heart surgery with HBOT showed great results with increased ischemic* times.

*  Ischemia is the term used for a restriction in blood flow, usually because of problems with the blood vessels, resulting in damage, dysfunction, and death of cells in the tissue.  Another term is local anemia, and whatever one calls this process, it causes congestion such as vasoconstriction, thrombosis or embolism.  Ischemia results in tissue damage and/or death because of a lack of oxygen and other nutrients.

While hypoxia means a shortage of oxygen, ischemia is an absence or shortage of blood supply to an organ including lowered delivery of not only oxygen, but glucose and other necessary nutrients to the cell.  It also results in the build-up of toxic metabolic waste products such as carbon dioxide and lactic acid since the blood circulation is not capable of carrying them away from the injured site.

The heart, kidneys, and brain are the organs most quickly damaged by ischemia.  It is a component of heart disease, stroke, atherosclerosis, blood clots, frostbite, crush injuries, etc.

Ischemia in the brain or heart causes what’s called an “ischemic cascade” where damaging enzymes, oxygen free radicals, and other toxic chemicals damage and/or destroy cells and tissues.

Reperfusion injury is the restoration of blood flow (perfusion) after ischemia and can actually be far more damaging than the original ischemia.  When reperfusion occurs it kicks off the inflammatory response, damaging cellular proteins including the DNA.  Leukocytes (white blood cells) may build up in the capillaries thereby causing a vicious cycle of more ischemia and cell death.

The Undersea Medical Society formed in 1967 to support the further scientific research of diving and undersea medicine as applications of hyperbarics grew in the clinical sector.  The society expanded to include hyperbaric medicine and, as a result, in 1976 changed its name to Undersea and Hyperbaric Medical Society. It established the Hyperbaric Oxygen Therapy Committee to serve as a guide for practitioners of HBOT. Its publications continue to serve as private and public guides to HBOT, and are the guidelines used by the Centers for Medicare and Medicaid Services, as well as other third party insurers when it comes to reimbursement.

Meanwhile, an ad hoc Medicare committee was formed in 1972 to study the effectiveness of HBOT for special medical conditions. This was due in part to the explosive growth of research and medical evidence that had been developed in the preceding years.

Nineteen-eighty-nine ushered in the beginning of using HBOT to enhance healing times in athletes. Years later hyperbaric chambers would become a common instrument in the development and research behind sports medicine.

Proof that HBOT was highly effective in high-risk procedures led doctors to start experimenting with HBOT in other practices.  It was noted that HBOT also had antimicrobial, wound healing and anti-toxic effects on humans—so much so that modern practices use HBOT as the standard procedure for treating carbon monoxide poisoning, chronic wounds, crush injuries, radiation damage and infections in bone and soft tissue, even though very little research has been done on these treatments.

Treatments of neurological disorders and patients with brain injuries are primarily done in independent, privately owned, and non-institutional hyperbaric clinics.  While these ailments could just as easily be treated in a hospital setting, the lack of research, funding, and interest in HBOT alternatives to Western medicine keeps the treatment primarily to private care facilities.

13K. K. Jain, (2004). Textbook of hyperbaric medicine (2nd ed.) Toronto/Seattle/Bern/Göttingen: Hogrefe & Huber, 5.
14The discovery of oxygen: Hands on activity: Repeat Carl Wilhelm Scheele and Joseph Priestly Experiments. Accessed 6 Jan 2010
15Jain, 2004, 11.
16Ibid., 5.
17Ibid.,  6.
18D. Mathieu, (Ed.). (2006). Handbook on hyperbaric medicine. The Netherlands: Springer, 20-21.
19 T. S. Neuman, & S. R. Thom, (2008). Physiology and medicine of hyperbaric oxygen therapy. Philadelphia: Saunders Elsevier, 13.