Decompression Theory

Abstract

The French physician Paul Bert (1833–1886) recognized the problem of accidents during and after decompression and therefore recommended a slow ascent. John Scott Haldane developed dive tables for the US Navy in 1908. Fundamentals of his research are incorporated in today’s dive tables. His calculations included exponential saturation and desaturation, five different body compartments, gradual decompression in 3-m intervals and the concept of maximum supersaturation with the so-called Haldane factor [7]. He postulated that the partial pressure of inert gases in all tissues should not exceed twofold (2:1) of the ambient pressure during the ascent to avoid decompression accidents. In other words, a direct reduction to an ambient pressure from a twofold overpressure is regarded not to cause any DCS symptoms. For example, a direct ascent from 10 m after a saturation dive without deco stop is supposed to be safe. However, Workman corrected the value later to 1.58:1, considering only partial pressures of inert gases, primarily nitrogen. Haldane assumed that the main factor of a decompression accident during rapid ascents is caused by fast compartments. He postulated that slow compartments are responsible for decompression accidents during slow ascents and decompression stops. He established the basic principle of compartment saturation and desaturation based on tissue perfusion. He set the ascent rate initially to 18 m/min than later to 9 m/min.