THE EFFECT OF PULMONARY FUNCTIONS OF RAPID COMPRESSION IN SATURATION- EXCURSION DIVES TO 1000 FEET
NAVAL SUBMARINE MEDICAL RESEARCH LAB GROTON CT
Pagination or Media Count:
Four subjects were rapidly compressed at a rate of 2 - 3.5 feet per minute to 600 and 800-foot depths. They remained at saturation depths for 35 and 36 hours and carried out excursion dives lasting three hours to 800 and 1, 000 feet, respectively. Maximal Expiratory Flow Rate MEFR and Maximal Inspiratory Flow Rate MIFR measured with a Wedge spirometer at 200-foot increments during rapid compression showed a linear decrease with the increase in pressure. During the 35-36 hour saturation period, MEFR increased 33-35 and MIFR rose 16-30 from the initial values obtained at saturation depths. The recovery of MEFR was not limited to peak flow rates, but also pronounced at the MEFR measured at 50 of vital capacity, indicating that the recovery was independent of musclar effort. Airway collapse during rapid compression and reopening during the subsequent saturation period is proposed as the most likely explanation for the observed changes. Vital capacity decreased during the compression and decompression period and showed a tendency to increase during the saturation period. Evidence of air-trapping was seen in flow-volume loops measured at depth.
- Stress Physiology