HANA-KAI-II - 17-DAY DRY SATURATION DIVE AT 18.6 ATA .1. OBJECTIVES, DESIGN, AND SCOPE

Abstract

The dive (Hana Kai II) was designed to determine the effects on man of a prolonged exposure to a dry He-O2 hyperbaric environment. Comprehensive studies on energy balance, body fluid balance, cardiorespiratory functions, maximal O2 uptake, psychological performance and physiological responses to cold were performed at a simulated depth of 580 ft (18.6 ATA [atmospheres absolute pressure]) over a 30 day period. Following a 3 day predive control period at 1 ATA air (period 1), 5 male divers spent 17 days at 18.6 ATA in a He-O2 environment (periods 2-6) and returned to 1 ATA air after 7 days of decompression (periods 7-8). They stayed an additional 3 days inside the chamber for postdive control measurements (period 9). The chamber temperature was maintained 25-27.degree. C during periods 1 and 9, 30-31.degree. C during periods 2-5 and 27-28.degree. C during period 6. At 18.6 ATA, the Po2 partial O2 pressure] and PCO2 of the chamber gas were maintained at approximately 225 and 2 mmHg, respectively. Physical and physiological characteristics of individual subjects, the major daily activity schedule and the scope of investigation are presented.