History Of Hyperbaric Medicine

Francis Wattel

Service d'Urgence Respiratoire, de Réanimation Médicale et de Médecine Hyperbare, Hôpital Calmette, Centre Hospitalier et Universitaire, Lille, France

1. A HISTORICAL OVERVIEW

Hyperbaric Medicine goes back a long way, since its history derives from the history of diving which dates back to ancient times.

The history of Hyperbaric Medicine has been closely linked with the development of technology for underwater activities and the advance in knowledge about the physical laws and physiological mechanisms of breathing oxygen at pressures above atmospheric pressure. Three periods can be distinguished:

a time for discoveries: from the Renaissance to the Age of Enlightenment;

a time for hyperbaric therapy: from the middle of the 19th century to the beginning of the 20th century;

the practice of Hyperbaric Medicine on a scientific basis: since the second half of the 20th century.

1.1 A time for discoveries

Science and technical knowledge flourished from the very beginning of the Renaissance.

These are the main areas of scientific progress: in 1644 Torricelli invents the barometric tube; in 1653 Pascal confirms the variation of barometric pressure with altitude and establishes the laws of hydrostatics; Boyle (1661) and Mariotte (1676) both state the law relating the volume and pressure of

an ideal gas; in 1755 Black discovers carbon dioxide; in 1775 Priestley discovers oxygen; and in 1789 Lavoisier describes oxidation phenomena.

Diving activities had been limited to snorkelling, restricted in time by the duration of apnoea and in space by poor underwater vision. However, from the 16th century onwards, an enormous variety of ideas and projects flourished, such as a breathing tube between diver and surface, which was taken up by Leonardo da Vinci and, after some changes, by Borelli. In 1690 Edmund Halley suggested a system with a diving bell where the air was changed by means of a leather pipe using the air contained in weighted barrels sunk to the seabed. In London, at about the same time (1662), Henshaw was the first to think of using atmospheric pressure as a therapeutic modality. Denis Papin suggested using bellows to inject fresh air continuously into the diving bell. In 1791, Smeaton, an English engineer in charge of repairing bridge piers in Hexham, had the first chamber built in cast steel and fed it with compressed air from a pump on a boat. This 18th century-derived pressure chamber is still in use nowadays. During the same period, Fréminet developed a full-pressure suit and helmet with compressed air supplied through a pipe from bellows on the surface.

1.2 A time for hyperbaric therapy

The therapeutic use of hyperbaric oxygen (HBO) grew in France between the middle of the 19th and the beginning of the 20th centuries. In 1834, Junod described the beneficial effects of high-pressure oxygen on man. Pravaz in Lyon, and Tabarie in Montpellier, both described the positive effects of immersion in compressed air for various ailments. In 1876, Fontaine had a mobile operating theatre built which Péan used for 27 operations. From 1860 onwards, an amazing number of centres were opened in Europe (Amsterdam, Baden-Baden, Brussels, Haarlem, London, Malvern, Milan, Moscow, Munich, Odessa, Stockholm, Vienna, among others); and the first chamber was built in Canada, at Ashawa. The largest was built in 1927 in Cleveland, USA, by Cunningham. This was 6 storeys high and comprised 72 rooms. It was a failure because patients were not selected on proper scientific or clinical grounds.

Among all the people with an influence on the history of hyperbaric medicine, the most famous is certainly Paul Bert. His work "La Pression Barométrique" (1878) is universally known and is one of the foundations of Hyperbaric Medicine. He studied the effects HBO, discovered its toxic effects on living organisms and insisted on the risk of convulsions. He concluded that to avoid harmful effects, oxygen should not be inhaled at a concentration above 60% at 1 ata. The toxic effect of oxygen on the nervous system was later to be named "Paul Bert effect". Shortly afterwards, Lorrain Smith in Edinburgh described the effects of oxygen on the lungs. At around the same time, in 1895, Haldane was carrying out an experiment on the effects of carbon monoxide on oxygen tension, recommending as a result the use of HBO for the treatment of carbon monoxide poisoning.

1.3 Practicing Hyperbaric Medicine on a scientific basis

1.3.1 Over recent decades, progress has taken many directions

The increased number of experiments on the animal model, for instance, has brought about an improved understanding of the effects and physiological consequences of HBO: its capacity to increase oxygen delivery to the tissues, its effects on vascularisation and on anaerobic bacteria, its activity as a means of defence against infection and its contribution to wound healing.

The indications for HBO have been determined more precisely, as much for critical conditions as for long-term or chronic disease, and listing only those which have been validated by clinically controlled research following the criteria of Evidence Based Medicine (EBM).

There has been emphasis on increased safety and improved care for patients in hyperbaric chambers, including those who are critically ill and requiring continuous intensive care.

Lastly, the necessary means of education have been brought into play to promote the development of Hyperbaric Medicine as a speciality.

Looking back, progress has not been linear: the 1950's marked the pioneering decade. During the next 20 years, Hyperbaric Medicine underwent an intense phase of development: over 60 indications were listed. Between 1980 and 1994, there was a phase during which the usefulness of HBO underwent doubt and suspicion. The last decade (1994 - 2004) has been a phase of rigorous scientific.

Who's who in the development of HBO?

The first real scientifically based therapeutic approaches were made by Boerema in Amsterdam (1959) in the field of cardiac surgery with the asystolic heart, and Brummelkamp (1961) in the increasingly frequent treatment of gas gangrene. Since then the contribution of the Dutch school has been central in research on infections causing soft tissue necrosis, and their treatment by HBO. Ledingham in Britain, and Jacobson in the USA, were also among the pioneers of HBO.

It is worth noting that in different countries physicians in various fields of medicine and surgery were intent from the start in making progress in Hyperbaric Medicine.

In France, following the suggestion of L. Barthélémy from the Toulon naval Medical Institute, intensivists were the first to introduce HBO.

M. Goulon, A. Larcan, J.M. Mantz, Ph. Ohresser, C. Voisin, L. Lareng and J. Ducailar contributed to determining the indications of HBO for critically ill patients.

In the United States, the influence of surgery can be found from the start, including G. Hart and M. Strauss (indications for HBO in traumatology and plastic surgery); J. C. Davis and T. K. Hunt (problem wounds and HBO) and R. E. Marx (mandibular osteonecrosis and HBO).

In Italy, it was mostly anaesthetists/intensivists who took charge of HBO from the start including A. Gasparetto, A. Gismondi, A. Sparachia and others. In Spain, Internal Medicine specialists initiated Hyperbaric Medicine, including J. Desola who has done excellent work in coordinating centres there.

Where research on diving accidents is concerned, it is mostly those countries with a strong tradition of diving for military purposes which have made the greatest contribution to establishing diving profiles and recompression tables. These tables have quickly been used for treating recreational diving accidents.

1.3.2 What are the reference institutions for Diving and Hyperbaric Medicine?

On the one hand, there are the national and European scientific societies; and on the other, there is the European Committee for Hyperbaric Medicine (ECHM).

- The Scientific Societies

Their duties are to promote knowledge in the fields of Diving and Hyperbaric Medicine, organize scientific meetings and annual conferences and publish study reports. Among the oldest are the "Société de Physiologie et de Médecine Sub-Aquatiques et Hyperbares de Langue Française" (MEDSUBHYP), along with the two Italian societies, one created by the National Society for Anaesthesia and Intensive Care (SIAARTI), and the other specifically geared towards Hyperbaric Medicine (SIMSI). German (GTUM) and Dutch (NVD) societies are more involved with Diving Medicine. The Swiss society (SUHMS) and the British Hyperbaric Association (BHA) are involved in both aspects, whereas in Spain this role is taken by the Coordination Committee of Hyperbaric Centres. However, before 1989 there was not much cohesion between the various European countries. There was also a lot of activity in communist Eastern Europe; but we did not know much about that since even the Proceedings of the Moscow meeting of the International College on Hyperbaric Medicine (ICHM) in 1981 appeared only in the Russian language.

The European Undersea Biomedical Society (EUBS) was founded in 1965. The main goal of the EUBS was diving and underwater medicine. In 1993, the EUBS changed its name to European Undersea and Baromedical

Society in order also to include clinical Hyperbaric Medicine. This meant the start of a very fruitful cooperation and even integration between Diving and Hyperbaric Medicine. The same developments were seen in the USA, where the Undersea Medical Society (UMS), founded in 1967, changed its name to the Undersea and Hyperbaric Medical Society (UHMS) in 1986.

- The ECHM

The European Committee is not a learned society but an organization for the promotion of Undersea and Hyperbaric Medicine on a European scale. It is recorded that "during an informal and friendly discussion between some distinguished gentlemen involved in Hyperbaric and Diving Medicine, the necessity of founding a committee to improve the level of quality and acknowledgement of Hyperbaric Medicine emerged in February 1989 in Milan, Italy". The next step was a first informal meeting between the above-mentioned gentlemen (the founding members) in Lille, in November of the same year. The founding members (D. J. Bakker, J. Desola, A. Marroni, D. Mathieu, G. Oriani, P. Pelaia, J. Schmutz, F. Wattel (elected President) and J. Wendling) decided to act as the Executive Board of the Committee. The first plenary meeting (with representatives of all European countries) was held in Amsterdam in August 1990. This occurred during a joint meeting between the ICHM, the UHMS and the EUBS, the first in history. The official founding, according to all necessary rules and regulations, of the European Committee took place in Milan in 1991. The goals for the Committee were defined as:

• Studying and defining common indications for hyperbaric therapy, research and therapy protocols, common standards for therapeutic and technical procedures, equipment and personnel, cost-benefit and cost-effectiveness criteria.

• Acting as a representative body for the European health authorities of the European Community (EC) in Brussels (Belgium).

• Promoting further cooperation among existing scientific organisations involved in the field of Diving and Hyperbaric Medicine like Divers Alert Network (DAN); Confédération Mondiale des Activités Subaquatiques (CMAS); the European Diving Technical Committee (EDTC); the UHMS, which acts as an international society although it is American; the Japanese Undersea and Hyperbaric Medicine Society; the South Pacific Underwater Medical Society; and the South African Undersea and Hyperbaric Medical Society.

One of its main activities is the organization of European Consensus Conferences and Workshops. Four workshops and seven Consensus Conference have been organized over ten years. The last one took place in Lille in December 2004 in order to review all the documents and literature published since the first Conference in 1994. The ECHM list of accepted indications was up-dated, and guidelines for organization, safety, education and research in Hyperbaric Medicine were issued, for the next 10 years.

2. STATE OF THE ART IN HYPERBARIC MEDICINE

The main aspects defining hyperbaric medicine today deal with indications, design and safety requirements for HBO chambers and medical equipment, staff training and continuing education requirements and research protocols.

2.1 Current justified indications for HBO

An agreement was reached on indications during the Consensus Conference which was held by the ECHM in Lille in September, 1994, and updated 10 years later in Lille in December, 2004. To be deemed acceptable, an indication had to be based on experimental and clinical studies carried out with strict methodology and producing significant positive results.

In fact, one of the ways of assessing the efficiency of HBO is by referring to the best data available from basic research, animal studies with control groups and human studies following EBM procedures. This approach involves: prospective, controlled, randomized clinical studies; quantified results; collection of results through the Cochrane collaboration; and meta-analysis of the various clinical studies.

The Jury issued its recommendations using a three-grade scale according to the strength with which each recommendation has been evaluated.

Type 1 - Strongly Recommended: the Jury considers the implementation of the recommendation of critical importance for final outcome for the patient/quality of practice/future specific knowledge.

Type 2 - Recommended: the Jury considers the implementation of the recommendation as positively affecting final outcome for the patient/quality of practice/future specific knowledge.

Type 3 - Optional: the Jury considers the implementation of the recommendation as optional.

The Jury also reported the level of evidence supporting the recommendations.

Level A - recommendation supported by level 1 evidence (at least 2 concordant, large, double-blind, controlled randomized studies with little or no methodological bias).

Level B - recommendation supported by level 2 evidence (double-blind controlled, randomized studies but with methodological flaws; studies with only small samples, or only a single study).

Level C - recommendation supported only by level 3 evidence (consensus opinion of experts).

Table 1. Accepted indications for HBO therapy (7th ECHM Consensus Conference, Lille, 2004)___

CONDITION

ACCEPTED

Level of Evidence

AB

C

Type I

CO poisoning

X

Crush syndrome

X

Prevention of osteoradionecrosis after dental extraction

X

Osteoradionecrosis (mandible)

X

Soft tissue radionecrosis (cystitis)

X

Decompression accident

X

Gas embolism

X

Anaerobic or mixed bacterial anaerobic infections

X

Type II

Diabetic foot lesion

X

Compromised skin graft and musculocutaneous flap

X

Osteoradionecrosis (other bones)

X

Radio-induced proctitis/enteritis

X

Radio-induced lesions of soft tissues

X

Surgery and implant in irradiated tissue (prophylaxis)

X

Sudden deafness

X

Ischemic ulcer

X

Refractory chronic osteomyelitis

X

Neuroblastoma Stage IV

X

Type III

Post anoxic encephalopathy

X

Larynx radionecrosis

X

Radio-induced CNS lesion

X

Post-vascular procedure reperfusion syndrome

X

Limb reimplantation

X

Burns >20 % of surface area and 2nd degree

X

Acute ischemic ophthalmological disorders

X

Selected non-healing wounds secondary to inflammatory

X

processes

Pneumatosis cystoides intestinalis

X

2.2 Hyperbaric equipment

Over the last decades, efforts regarding equipment have dwelt on safety and reliability. The rules and regulations enforced on manufacturers and users are stringent, particularly regarding fire hazards. Further progress has been made through the medicalisation of chambers: there is more room, and entry is made easier by rectangular doors. Nowadays, intensive care can be provided just as efficiently in a hyperbaric chamber as in an ICU.

- A therapeutic hyperbaric chamber shall be considered as a medical device according to the European Council Directive 93/42 "Medical Products".

- The performance, testing and safety requirements of new therapeutic multiplace chamber systems shall conform with the new European norm prEN 14931 CEN TF 127. All new chambers will be CE marked. Existing chambers should strive to reach the same safety levels as required by that norm.

- Quality assurance should be implemented in hyperbaric centres.

- Approval of medical devices for hyperbaric use is a worldwide problem. With a few exceptions, there is a lack of CE marked medical devices for use in the hyperbaric chamber. A risk evaluation according to the European norm ISO 14971 should be performed before bringing medical equipment into the chamber. Publishing and sharing experience and information on risk analyses between European HBO centres are recommended. The manufacturers shall be encouraged to extend the CE approval of their medical devices for hyperbaric use.

The range of indications for HBO has led to the idea of equipment functionality. To avoid treating a patient in critical condition and an outpatient in the same chamber, it is useful to have a series of chambers linked together with airlocks. One chamber is kept for emergency and intensive care indications, another for programmed therapy of chronic diseases. Lastly, there are chambers with specific equipment for performing function testing for divers, hyperbaric workers or patients requiring HBO.

- The Jury strongly recommends that the European Code of Good Practice for Hyperbaric Oxygen Therapy (ECGP) be the minimum requirement to be fulfilled by European hyperbaric centres, as it was established by strong consensus between internationally recognized European experts.

- The operations must be conducted under standard operation procedures described in a specific manual. Each hyperbaric centre must develop emergency procedures in the same way. The staff must review these regularly, and should be trained in these procedures.

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