Chapter 28 

 PHYSIOLOGICAL STUDIES IN SEALAB II 



G. F. Bond 



U. S. Navy Special Projects Office 



Washington, D. C. 



Although Sealab 11 was not designed to yield a large amount of physiological data, it was 

 nevertheless considered prudent to pursue a course of selective monitoring of personnel of each 

 of the three teams for overall safety of the operation. Previous meticulous physiological stud- 

 ies, conducted through the Genesis series,'' and subsequently in Sealab I, had indicated that the 

 great majority of physiological parameters examined would show no significant change under 

 conditions of high pressure and exotic gas mixtures. It was therefore considered adequate to 

 monitor only those vital functions of our human subjects which might assist topside control in 

 medical management of the experiment. 



In consequence, the number of physiological tests performed in Sealab II was severely cur- 

 tailed, and the selection of monitored subjects was likewise limited. A program was established 

 to provide for intensive physiological sampling from two or three aquanauts of the first two 

 teams on a daily, alternate daily, then each-third-day basis. Sampling included extraction of 

 about 20 cubic cemtimeters of blood daily for topside analysis, with appropriate quantities of 

 urine and saliva for additional inspection. In addition, the majority of aquanaut personnel par- 

 ticipated in daily studies of pulmonary function, electrocardiographic recordings, body- 

 temperature control, exercise tolerance, and a number of routine physical tests. 



By and large, the results of tests on selected subjects in the three teams of Sealab n were 

 essentially negative. All of the classical blood chemistries which were performed fell easily 

 within the normal ranges during the experiment. These tests included blood sugars, blood urea 

 nitrogen determinations, creatinines, all serum electrolytes, and calcium and phosphorus values 

 and ratios. Blood morphological values were likewise followed on a regular basis, with no evi- 

 dent deviation from the normal pattern. Urine specimens remained generally within acceptable 

 limits, considering the problems of accurate collection and analysis. 



Nevertheless, the following chapters will show, there were suggestive trends in certain 

 areas which will warrant further intensive investigation under controlled laboratory conditions, 

 and with considerable refinement of techniques. For example, the red-blood-cell count of the 

 subject (MSC) who was exposed for 30 days of continuous stay to partial pressures in excess of 

 200 mm Hg of oxygen, showed a linear decrease in red-cell count, although no evidence of cell 

 destruction could be demonstrated. Likewise, most of the "Stress" enzymes and other indica- 

 tors of stress were clearly elevated during the first three to five days of hyperbaric exposure- 

 indicative of some initial problems which require further investigation. 



During Sealab II, attention was particularly directed to examination of the "stress enzymes," 

 since these indicators, together with the corticosteroid determinations, had demonstrated great- 

 est liability during past human exposures. As will be seen in the following chapters, these data 

 give provocative evidence of an increased stress effect on the aquanaut subjects during the first 

 three-to-five-day period of undersea exposure, with a slow return to normal values. Of the 



*Extreme pressure-chamber studies by Capt George Bond at the Submarine Medical Center 

 New London, Connecticut which demonstrated that men could live in an artificial helium- 

 oxygen atmosphere at a simulated depth of 200 ft for prolonged periods and not realize any 

 harmful effects. 



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