PULMONARY GAS EXCHANGE AND URINARY ELECTROLYTE EXCRETION DURING SATURATION-EXCURSION DIVING TO PRESSURES EQUIVALENT TO 800 AND 1000 FEET OF SEAWATER

Abstract

Abstract : Pulmonary gas exchange and related renal regulation as indicated in urinary electrolyte exchange were measured during saturation-excursion dives to 800 and 1000 feet of sea water (FSW) for the purpose of determining beginning physiological limitations of underwater operations at these depths. Alveolar CO2 tension, oxygen consumption, and CO2 excretion did not change significantly from pre-dive control values during rest and exercise (100 watt) at 800 and 1000 FSW, which indicates that there is no respiratory limitation for moderate work load at the depth of 1000 FSW. Urinary electrolyte excretion showed a characteristic pattern during the saturation-excursion period, consisting in increased urine volume, large rise in bicarbonate excretion, and decrease in chloride excretion. Bends which did not respond to recompression and were found to be associated with large increases in bicarbonate excretion appear to be caused by excessive fluid shifts. It is suggested that in such cases liquid therapy should be instituted to compensate for the loss of liquid during the dive.