Abnormal Pressures: Hyperbaric and Hypobaric

Abstract

This chapter deals with the interrelated physiological effects of the continuum of altered ambient pressure. These pressures may be both higher and lower than the sea level pressure to which we are accustomed and in which we have evolved. The chapter first discusses what pressure is, and where and why alternative pressures are encountered by humans. It reviews the occupational, medical, and recreational incentives for forays into both environments, high and low. It points out the role of time in evaluating pressure exposures and the importance of transitions to and from higher and lower pressures. Then, it covers first the effects of elevated pressures, then the effects of lack of pressure, emphasizing the importance of breathing gases in most alternative pressures. Last, it pays particular attention to the main pressure‐related disorder, decompression sickness, and its treatment. This is a book on industrial hygiene and toxicology, so the chapter deals primarily with healthy individuals fit for the workplace, but does mention the special concerns about pressure needed for people who have various diseases.