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Hyperbaric oxygen therapy
(Portuguese PDF version)

Francisco Humberto de Abreu Maffei¹

1. Professor, School of Medicine of Botucatu, Universidade Estadual Paulista.

J Vasc Br 2003;2(3):169-170

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The current issue of Brazilian Vascular Journal presents two articles on hyperbaric oxygen therapy (HBO). One of these articles is a review on the use of HBO in the treatment of clostridial gas gangrene and necrotizing fasciitis. The other article presents three cases of arterial disease that were treated with hyperbaric oxygen therapy as a complementary therapy.

Although this therapy has been used since the 60's to treat different kinds of diseases,¹ based on the increase of tissue oxygenation due to the increase of oxygen dissolved in the plasma when it is inhaled in high pressure environments, the extensive use of HBO still remains a controversial issue. In spite of the great number of articles on this subject,--there are more than 300 pages of references in the Medline database--most studies are restricted to descriptions of cases and uncontrolled or inappropriately controlled clinical trials,² which provides insufficient evidence to validate its use in different clinical situations.

Despite the absence of randomized studies, in severe situations of gas gangrene and necrotizing fasciitis, the follow-up of cases compared to controls such as the ones mentioned in the review of Lima et al. might justify the use of HBO, whenever it is available, provided it is performed after the first indispensable treatment with fasciotomies and large tissue debridements associated with antibiotic therapy. However, controlled studies and metanalysis have demonstrated that hyperbaric oxygen therapy is not efficient and might even be harmful in other severe and acute situations, such as strokes and brain lesions, which could seem appropriate for being treated with HBO as a primary procedure.^3,4

In chronic ischemic lesions such as the ones described by Costa Val et al., the use of HBO is much more controversial, and, although the article raises interest because it presents a potential complementary therapy, the validity of its use and the cost-benefit relationship need to be carefully assessed. A reason to justify this caution is that, certainly, every angiologist and vascular surgeon can recall cases similar to the ones described in the article by Costa Val that were clinically treated without HBO, and presented similar outcome. Thus, even if it is only used as a complementary method according to the authors' description, controlled studies must be carried out in order to validate this therapy and to prove its therapeutic effects, especially when the patient is submitted to a showy procedure such as being placed into a hyperbaric chamber, in addition to being treated with dressings and conventional drugs.

In a recent systematic review of the literature about the use of HBO in the treatment of wounds, Wang et al.² concluded that, even though this therapy might be useful to treat some lesions, there are not enough evidence to determine which patients would really enjoy its benefits and which moment is adequate to begin the treatment. The authors also pointed out that severe adverse events might occur and high quality randomized and controlled clinical trials must be performed in order to assess the long and short term risks and benefits so that more appropriate clinical decision can be made.

Therefore, in my opinion, in spite of being an attractive therapeutic method, sufficient evidence has not been provided yet to justify, for example, the acquisition of a hyperbaric chamber for patients with vascular diseases. On the other hand, the performance of well-designed clinical trials by physicians who have access to this kind of equipment is recommended in order to confirm or deny the validity of HBO use.

REFERENCES

1. Kindwall EP. Hyperbaric oxygen. Br Med J 1993;307:515-16.

2. Wang C, Schwaitzberg S, Berline E, Zarin DA, Lau J. Hyperbaric oxygen for treating wounds: a systematic review of the literature. Arch Surg 2003; 138:272-9.

3. Alternative Therapy Evaluation Committee for the Insurance Corporation of British Columbia. A review of the scientific evidence on the treatment of traumatic brain injuries and strokes with hyperbaric oxygen. Brain Inj 2003;17:225-36.

4. Rusyniak DE, Kirk MA, May JD, et al. Hyperbaric oxygen therapy in acute ischemic stroke: results of the hyperbaric oxygen in acute ischemic stroke trial pilot study. Stroke 2003;34:571-4.