Review Article Singapore Med J 2011; 52(12) : 901 The development of hyperbaric and diving medicine in Singapore Chng J, Low C T E, Kang W L ABSTRACT HBOT has had a long history that began when the Hyperbaric oxygen therapy is a noninvasive first hyperbaric treatment chamber or ‘domicilium’ therapy used in the treatment of diving-related was constructed in 1662 by a British clergyman named medical illnesses. It is an important adjunct in the Henshaw, who utilised it to treat a multitude of medical management of a variety of medical conditions. conditions.(3) Since then, there have been many reports of The Republic of Singapore Navy Medical Service the beneficial effects of increased pressure, and by 1877, (NMS) is the main driver of the development of chambers were used widely for many conditions.(4) In 1879, hyperbaric and diving medicine in Singapore. the use of hyperbaric therapy to prolong safe anaesthesia The practice of hyperbaric medicine has during surgery was realised.(5) In the early 1900s, the use of inherent risks, and unregulated application of HBOT to treat medical problems became more prevalent. this therapy may do more harm than good. NMS The late 1950s and early 1960s are believed by many to be and Singapore General Hospital (SGH) signed the birth of modern-day hyperbaric medicine. One large a Memorandum of Understanding to combine contribution was made by Dr I Boerema. He conceived NMS’s experience with the clinical expertise the idea of ‘drenching’ tissues with oxygen by increasing of SGH to provide holistic care for diving and the ambient pressure surrounding the patient. The ensuing clinical hyperbaric treatment patients. This experiments, where fatally anaemic pigs were successfully collaboration would increase the profile of treated with volume expansion and pressurised this clinical specialty in Singapore, and help to hyperoxygenation, were so promising that he had a large establish safe clinical practice guidelines, training operating-room chamber built at the Wilhelmina Gasthuis, and accreditation requirements for diving and the academic hospital of the University of Amsterdam. hyperbaric medicine practitioners in Singapore, There, he conducted surgical operations under pressure Navy Medical thus ensuring that the practice of bona fide Service, for a variety of conditions, including surgical correction Republic of hyperbaric medicine is safeguarded and patient of transposition of the great vessels, tetralogy of Fallot and Singapore Navy, 126 Tanah Merah care is not compromised. pulmonary stenosis.(6) Coast Road, Singapore 498822 In the 1970s, with the use of HBOT producing Keywords: compressed air works, diving and seemingly dramatic results in potentiating the effects of Chng J, MBBS, DFD Head, Hyperbaric hyperbaric medicine, hyperbaric oxygen therapy, radiotherapy,(7) prolonging circulatory arrest time during Medicine Section Republic of Singapore Navy Medical Service, cardiac surgery and treating anaerobic infections(8) and Kang WL, MBBS, Singapore General Hospital Hyperbaric and (9) MRCSE, FAMS carbon monoxide poisoning, researchers were eagerly Chief of Medical Corp Diving Medicine Centre seeking other uses for HBOT. Patients with a variety of Strategic Human Singapore Med J 2011; 52(12): 901-905 other chronic conditions were treated in chambers, often Resource/ Office of Academic without much scientific rationale. Patients suffering from Medicine, INTRODUCTION emphysema, stroke, senility, arthritis and other debilitating Singapore Health Services, Hyperbaric oxygen therapy (HBOT) is a noninvasive conditions that had not responded to conventional therapy 31 Third Hospital Ave, #03-03, therapy used in the treatment of diving-related medical were treated in the hope that some change might be noted. Bowyer Blk C, Singapore 168751 illnesses, and is an important adjunct in the management Unfortunately, many of these experiments were poorly of a variety of medical conditions such as poorly healing controlled and ‘good results’ were usually reported Low CTE, MBBS, FRCA, MPH wounds and carbon monoxide poisoning. HBOT is defined anecdotally. Meanwhile, the development of improved Group Director and Visiting Consultant, as a treatment in which a patient intermittently breathes cardiopulmonary bypass equipment had progressed, and HDMC, SGH 100% oxygen while the hyperbaric chamber is pressurised with the advent of better heart-lung machines and deep Correspondence to: to a pressure greater than that at sea level.(1) This increases hypothermia, the need for performing surgery under Dr Chng Jeremiah Tel: (65) 9172 8590 the absorption of oxygen by the tissues, enhances hyperbaric conditions decreased dramatically. By the Fax: (65) 6796 4198 Email: chngjeremiah antimicrobial activity, reduces tissue hypoxia and promotes early 1970s, early enthusiasm and good quality research @hotmail.com angiogenesis, thus accelerating the healing process.(2) had declined. Singapore Med J 2011; 52(12) : 902 Just as important as the lack of scientific progress in fishermen divers (some of whom were foreigners) who the research fields were the problems in the regulatory developed severe decompression illnesses as a result area. There was no general textbook available for of diving with only rudimentary diving knowledge and hyperbaric treatments and no distinction was made techniques. Knowledge and experience in the practice of between conditions for which good evidence of the diving and hyperbaric medicine was thus slowly built up efficacy of hyperbaric oxygen existed and those for within the Navy in the 1970s. which such evidence was sparse. To help establish such guidelines, a panel of Undersea Medical Society members THE COMPRESSED AIRWORKS ERA in the clinical hyperbaric field was formed. However, In 1982, the Singapore Government announced its that panel met informally only once, for a few hours, decision to build the Mass Rapid Transit (MRT) System, and issued some broad recommendations that were only and the RSN was approached in August that year to slowly implemented over the ensuing years. By 1976, a provide the overall medical support for the project.(11) number of hyperbaric clinicians in the Undersea Medical RSN’s Diving and Hyperbaric Medical Centre (DHMC) Society had become appalled by the indiscriminate use of was the only centre with the necessary experience and hyperbaric oxygen. These concerns led the society to form facilities to perform pre-employment selection and a Committee on HBOT in the mid 1970s. This committee is treatment of injured compressed air workers. In the now the international authority on HBOT, and continuously initial phase, DHMC helped the then-Ministry of Labour reviews research and clinical data on the use of hyperbaric to draft the regulations that would govern the conduct oxygen treatment so as to provide evidence-based of Compressed Air Works (CAW). DHMC was heavily recommendations on the indications, clinical efficacy and involved with the screening of all the potential compressed cost effectiveness of HBOT. In 1986, the members at the air workers, many of whom were from other nationalities. Undersea Medical Society annual scientific meeting voted CAW was used by six contractors from September to change the name of the Undersea Medical Society to 1984 to April 1987 for the construction of 11 km the Undersea and Hyperbaric Medical Society (UHMS), of the total 20 km underground tunnels. to embrace both the diving and clinical hyperbaric fields. Over the three-year period, a total of 2,932 workers Since then, the UHMS has become widely recognised as were screened for fitness to work in compressed air the international body regulating the practice of hyperbaric environment, of which 1,737 or 72.6% were found to be and diving medicine. fit to work in the project. 188,538 decompressions were carried out during the entire project, and from these, only HYPERBARIC MEDICINE IN SINGAPORE 164 cases of decompression illness were seen. 160 of these The history of diving medicine in Singapore can be were classified as Type 1 or mild decompression sickness, traced back to the 1960s when the Royal Malaysian while the remaining four were considered to be the more Navy (RMN) Headquarters was based in Woodlands, severe Type 2. This gave an overall incidence of 0.087%, Singapore. A multiplace recompression chamber, which which was quite favourable when compared to other CAW was initially used by the British Royal Navy before they data available at that time. The presence of onsite chambers left Singapore, was used as part of the dive training of allowed for early and often immediate treatment, which RMN divers. This carried on until the 1970s.(10) Clinical resulted in 100% recovery for all injured workers and no hyperbaric medicine in Singapore started when the disability. Throughout this period, RSN provided continual Orthopaedic Department in Singapore General Hospital onsite consultancy and medical services for Singapore’s (SGH) obtained a monoplace chamber, the ‘Normalair MRT project, thus making significant contributions to the Garette’, for HBOT. However, the usage was low and few most important public transport project of that time, while physicians understood the basis for HBOT at that time. cementing her position as the subject matter expert in This monoplace chamber was subsequently handed over hyperbaric and diving medicine. to the Republic of Singapore Navy (RSN) to support the fledging development of hyperbaric, diving and CLINICAL HYPERBARIC MEDICINE ERA submarine medicine in the Navy