Hyperbaric literally means increased pressure (hyper = increased, baric = pressure). Therefore, Hyperbaric Medicine is the art or science of restoring and/or preserving health through employing increased pressure. Although hyperbaric medicine has a history dating centuries back; modern practices, terminology, and the equipment utilized to employ hyperbaric oxygen therapy, mild hyperbaric oxygen therapy, and mild hyperbaric therapy aren’t more than a few decades old.
Although there are rumors of hyperbaric environments utilized in the days of Hippocrates, which would put the birth of hyperbaric medicine nearly two and a half thousand years ago; little concrete evidence has surfaced to boldly make this claim. The most recognized birth date of hyperbaric medicine would have been with British Clergyman Henshaw in 1662. It should be noted that only a few years earlier Robert Boyle published “New Experiments Physio-Mechanical, Touching the Spring of Air and its Effects”. This piece, published in 1660 included Boyle’s Law. Boyle’s Law states that at a constant temperature, the absolute pressure and the volume of gas are inversely proportional. As pressure increases, the gas volume is reduced; as pressure is reduced, the gas volume increases. Some may argue that Robert Boyle paved the way with his contributions to physics and chemistry and therefore the birth would reside with his research. However, it was Henshaw who applied these laws medicinally.
Henshaw’s “Domicilium” was driven by organ bellows, with valves to control the flow of air. It should be noted that his Domicilium could be used to create both hyperbaric and hypobaric environments. Henshaw believed that acute conditions would benefit from increased air pressure, while chronic conditions would respond better to decreased air pressure. Henshaw utilized his Domicilium to “help digestions, to promote insensible respiration, to facilitate breathing, and expectoration and consequently, of excellent use for prevention of most affections of the lungs.” Henshaw was of course only providing increased pressure without an increase in oxygen concentration, as oxygen was not discovered until 1773 by Carl Wilhelm Scheele, and the term “oxygen” was not coined until 1777 by Antoine Lavoisier.
More than a century after Henshaw, the Dutch Academy of Sciences sponsored a prize in 1782 and subsequent years, for the design of an apparatus to study the effects of higher pressures in biology. There were no contenders, nor any recipients of the prize. It wasn’t until the 1830’s when the next major advancements in hyperbaric medicine would occur. Increased pressures from 2 to 4 ATA where utilized with reports of increased circulation to the internal organs, improvements in cerebral blood flow, and production of feelings of well being. Junod, in 1834, was the first to report these findings out of France in the 1830’s. Later in 1837, Pravaz of France constructed the largest hyperbaric chamber of that time. The chamber was utilized to treat a variety of pulmonary conditions as well as cholera, rickets, menorrhagia and conjunctivitis.
North America in the 1800's
Hyperbaric medicine next hit the North American continent in 1860 with the first hyperbaric chamber constructed in Oshawa, Ontario, Canada. Only one year later, Corning would build the first hyperbaric chamber in the United States, in New York to treat 'nervous and related disorders'. But just as the United states began its journey into hyperbaric medicine, hyperbaric chambers were available in nearly all major European cities.
Europe in the 1800's
In 1877, Fontaine out of France developed the first mobile hyperbaric operating theatre. The chamber was recommended to facilitate the reduction of hernia, and for patients with asthma, emphysema, chronic bronchitis and anemia. Twenty-seven operations were performed within a 3 month period in this chamber. Success was so great that a large hyperbaric surgical amphitheatre which would hold 300 people was planned, although unfortunately never actually came into being. Fontaine suffered an accident while at the Pneumatic Institute resulting in his death.
Even with the prevalence of hyperbaric chambers available throughout Europe and continual advances in hyperbaric medicine, there were those who recognized its potential was not being tapped into. Similar to modern day advocates who feel hyperbaric should be at the heart of medicine; in 1885, Williams commented in the British Medical Journal, "The use of atmospheric air under different degrees of atmospheric pressure, in the treatment of disease, is one of the most important advances in modern medicine and when we consider the simplicity of the agent, the exact methods by which it may be applied, and the precision with which it can be regulated to the requirements of each individual, we are astonished that in England this method of treatment has been so little used".
America hit the map again when in 1921 Orville J. Cunningham built a hyperbaric chamber in Lawrence, Kansas. Here he treated victims of the Spanish Influenza epidemic that swept across the United States during the close of the First World War. Cunningham had observed that mortality from this disease was higher in areas of higher elevation, and he theorized that a barometric factor was involved. He reported remarkable results; however, a mechanical failure at night resulted in a complete decompression resulting in the death of all his patients. A tragic event, but not enough to stop Cunningham from further pursuing hyperbaric in the treatment of diseases such as syphilis, hypertension, diabetes mellitus, and cancer. Cunningham believed that anaerobic organisms played major roles in the etiology of these conditions and that the additional oxygen would be toxic to their survival. In 1928, Cunningham built the largest chamber in the world. Located in Cleveland, Ohio; the chamber was a five story high, 64 feet diameter steel chamber. Each floor had 12 bedrooms with all the amenities of a good hotel.
Despite requests by the Bureau of Investigation of the American Medical Association, very little information was released from Cunningham as evidence to validate his claims. Some believe he simply did not want to cooperate with the AMA, while other postulate he was fraud and was unsafe and unethical. Regardless, the chamber was dismantled in 1937 which brought about a temporary halt in the advancement of hyperbaric medicine for medical disorders.
The next advances would be in treatment of decompression sickness and the birth of modern diving medicine. In 1917 Drager devised a system for treating diving accidents; however, he was unable to ever get it into production. In 1935, Behnke showed that nitrogen is the cause of narcosis in humans subjected to compressed air above 4 ATA. Then in the very same year Cunningham’s chamber was demolished, Behnke and Shaw used hyperbaric oxygen in the treatment of decompression sickness.
Then came about the 50’s and 60’s, of which many believe to be the birth of modern-day hyperbarics. One large contribution was made by Dr I. Boerema while visiting Amsterdam in 1956. Boerema reported hyperbaric oxygen (HBO) as an aid in cardiopulmonary surgery, particularly for congenital conditions such as tetralogy of Fallot, transposition of great vessels, and pulmonic stenosis. A colleague of Boerema's, W. H. Brummelkamp discovered in 1959 (and subsequently published in 1961) that anaerobic infections were inhibited by hyperbaric therapy. Meanwhile, Boerema published, "Life without blood," a report of fatally anemic pigs treated successfully with volume expansion and pressurized hyperoxygenation. Boerema is often credited as the father of modern-day hyperbaric medicine.
In 1962, Smith and Sharp reported the enormous benefits of HBO in carbon monoxide poisoning. International interest thus was rekindled, and HBO therapy was thrust into the modern era. Hyperbaric units subsequently were built at Duke University, New York Mount Sinai Hospital, Presbyterian Hospital and Edgeworth Hospital in Chicago, Good Samaritan in Los Angeles, St. Barnaby Hospital in New Jersey, Harvard Children's Hospital, and St. Luke's Hospital in Milwaukee. Further chambers were installed in numerous international sites.
In 1967 Undersea Medical Society founded in the USA. Now known as the Undersea and Hyperbaric Medical Society. This non-profit organization organizes annual scientific meetings at different U.S. and international locations to permit review of the latest in research and treatment and to promote the highest standards of practice
In 1974 Sechrist Industries, Inc. developed the first monoplace hyperbaric chamber of widespread use. Capable of 3.0 ATA these chambers have provided an alternative to the high capital investment of multiplace chambers for high pressure treatment.
During the early 1970s, Dr. Neubauer became interested in potential applications of HBOT. He went on to establish and direct the Ocean Hyperbaric Neurologic Center in Lauderdale-by-the-Sea, FL. His research and clinical practice led to the conclusion that with a hyperbaric chamber, pressurized oxygen could be provided to damaged central nervous system neurons and help restore their function.
In the late 1980’s, Dr. Paul Harch began an in-depth study of brain decompression illness (DCI). As he evaluated divers with brain DCI, it became obvious to Dr. Harch that it was not residual gas being treated rather ischemic brain injury. This was confirmed in 1990 and 1991 with two diving cases. Following a call to Dr. Neubauer in April, 1990, Dr. Harch began treating the first diver and eventually achieved clinical, psychometric, and SPECT brain blood flow improvement. The second diver experienced normalization of his EEG, complete recovery of neurological function and a 22 point recoup of his pre-accident IQ before the end of his treatment protocol.
SPECT & HBOT
Simultaneously, Drs. Van Meter and Sheldon Gottlieb, a colleague of Dr. Neubauer and director of research at the Baromedical Research Institute of New Orleans, were conducting a trial of hyperbaric oxygen therapy in brain injured boxers with a small grant from the Hirsch Foundation. Encouraging preliminary results from this study and results from the divers and the small series of chronic traumatic brain injured and stroke patients spawned the Perfusion/Metabolism Encephalopathy Study of Drs. Harch, Gottlieb, Van Meter, and Staab. Begun in 1993 and completed in 1999, the study permitted the evaluation and treatment with hyperbaric oxygen therapy and SPECT brain imaging of a large number of patients with a variety of chronic neurological diseases, including decompression sickness, stroke, traumatic brain injury, carbon monoxide poisoning, cerebral palsy, near-drowning, toxic brain injury, cardiac arrest, static encephalopathy of childhood, autism, and others.
Alongside the multitude of advancements in the utilization of hyperbaric oxygen therapy in the treatment of neuorological diseases, simultaneously hyperbaric medicine began another direction of its own. In 1990, an avid outdoorsmen, Igor Gamow; began a revolution in mild portable hyperbaric medicine (pressure less than 1.5 ATA). His contribution, the Gamow bag, provided high altitude climbers with an effective method to combat the deadly low air pressure at high altitudes. His invention was praised by Sir Edmund Hillary himself, the first person to lead an expedition to climb Mount Everest.
The Gamow bag, which was only large enough to fit a single person and utilized a foot pump to inflate, was the early predecessor to the mild portable hyperbaric chamber. Since the inception of the Gamow Bag, many companies have improved on the design. Today, mild portable hyperbaric chambers are large enough to fit multiple persons and utilize electronic compressors enhancing time to inflation and pressurization. However, the largest impact played by these units has not come from the portability, rather the low cost compared to the steel and glass chambers that preceded them. For the first time, a means of applying hyperbaric medicine in practice and in research, although only at mild pressures (1.3 ATA), became affordable.
Regardless of the safety and initial success physicians worldwide have had utilizing mild pressure hyperbaric therapy, it has not come without skepticism nor concerns. As of date, these portable hyperbaric chambers have only achieved FDA approval in the treatment of Altitude Sickness, therefore the acceptance of the AMA and insurance corporations has yet to be seen. Regardless of governing body acceptance, mild hyperbaric therapies continue to spread and evolve as fast if not faster than their higher pressure application counterparts.
Hyperbaric medicine has had a long journey, and continues to gain acceptance and momentum in nearly every field of medicine. Today, the hyperbaric community moves forward not solely by itself but as an integrative part of medicine. This growing acceptance as hyperbaric medicine not only as a primary treatment, rather as a complimentary treatment will define a new age in hyperbaric medicine as the synergistic relationship between pressure, oxygen, and other medical modalities are uncovered.