CHAPTER EIGHTEEN: Hyperbaric Oxygen Therapy

CHAPTER OBJECTIVES

At the end of this chapter, the learner will be able to:

1. Relate the physiologic effect hyperbaric oxygen therapy to wound healing

2. Identify the diagnoses for which hyberbaric oxygen therapy is indicated

3. Recognize the different types of chambers used for hyperbaric oxygen therapy

4. Discuss the Gas Laws as they relate to the physics of pressurization

5. State the contraindications for hyperbaric oxygen therapy

6. Recognize the possible adverse effects of hyperbaric oxygen therapy

INTRODUCTION

Hyperbaric oxygen therapy, in its simplest terms, means oxygen under pressure. Hyperbaric treatment pressures are compared to atmospheric or sea-level pressure. This chapter includes the history of air and oxygen under pressure, the physics and physiology of hyperbaric oxygen therapy (HBO₂), and the current uses of HBO₂ as it applies to wound healing. HBO₂, like any other treatment modality, has appropriate indications for its use that are supported by scientific evidence. Unfortunately, it is also used inappropriately for impairments that have no scientific merit and by unscrupulous purveyors who use and sell HBO₂ for profit in the treatment of disorders for which there is no scientific basis for supporting efficacy. Currently the Undersea and Hyperbaric Medical Society has approved 14 indications for which there is adequate scientific basis for treatment with HBO₂ (FIGURE 18-1). Responsible users and providers of HBO₂ must remain true to scientific roots while being ever-watchful for opportunities for scientific research into potentially new clinical uses for this remarkable treatment tool.

COMPRESSED AIR THERAPY

Hyperbaric therapy has been employed for hundreds of years for a multitude of purposes. The earliest reported uses of hyperbaric treatment date back to the 1600s and a British clergyman named Henshaw whose work marked the beginning of the compressed-air era during which all hyperbaric treatments were performed only with compressed air, as oxygen was not discovered until 1775 by Priestley. In 1662, Henshaw built a sealed chamber that he called a “Domicilium.”¹ Valved bellows controlled chamber pressures, which could be raised or lowered by the adjustment of the valve system. Henshaw believed that acute disease processes of all kinds would respond favorably to increased air pressure, while more chronic diseases would respond better to low pressure. If during the course of treatment, a disease was felt to have become chronic, Henshaw readjusted the valves to create a slight vacuum. Given the small pressure changes possible with such an apparatus, any perceived effects on those patients treated were most certainly based ...