Medical Testing

The physical evaluation program was thus carried out for NASA by the Lovelace Clinic in Albuquerque, N. Mex.  The 32 volunteers were divided into 5 groups of 6 men each and 1 group of 2.  This was the rate at which they could be handled by the clinic and by the Wright-Patterson Laboratory.  One group at a time reported for an exhaustive series of examinations while the other men remained at their home stations.  The first group entered the Lovelace Clinic on February 7, 1959, and the others entered on succeeding Saturdays.  Each candidate spent 7½ days and 3 evenings at the Lovelace facility.

The Senate report that described Project Mercury in detail noted that since all those examined were active test pilots, it was not anticipated that any would be disqualified as physically unfit "Rather," it was explained, "degrees of physical soundness were obtained and evaluation was dependent upon a comparison of each man to his fellow candidates."12

The comprehensive program of examination and evaluation procedures for determination of the physical, mental, and social well-being of the candidates was under the direction of Dr. A. H. Schwichtenberg, a retired general officer in the Air Force, who had joined the Lovelace Foundation as head of the Department of Aerospace Medicine.  So as to establish a comparative yard stick, the following program was carried out:

1. History, aviation and medical

2. Physical examination

3. Laboratory tests

4. Radiographic examinations

5. Physical competence and ventilatory efficiency tests

6. Final evaluation

The routine clinical examinations were given under normal conditions with the subject resting.  Special consultations were provided as necessary. The clinical examination is described below.13

The medical history of each astronaut was taken by Dr. Schwichtenberg and his staff.  This included a conventional medical history together with a family history; the attitude of the immediate family toward hazardous flying; the subject's growth, development, and education; recent travels to areas where parasite diseases are endemic; and any disorders precluding pressure, inflation of the ears, sinuses, or lungs. The Cornell Medical Index Health questionnaire was used.

The aviation history included information about the pilotís total flying hours in various aircraft and about military experience in peace and wartime including details of combat missions, accidents, bailouts, use of the ejection seat, explosive decompressions, and altitude indoctrination and operational experience with partial-or full-pressure suits.

The physical examinations were made by an internist and flight, surgeon, Dr. R. R. Secrest.  The candidates were also examined by an ophthalmologist, Dr. E. H. Wood; an otolaryngologist, either Dr. H. W. Meredith or Dr. D. E. Kilgore, Jr.; a cardiologist, Dr. J. K. Conrad; a neurologist., Dr. B. T. Selving; and a surgeon, Dr. W. R. Lovelace II or Dr. A. McKinnon. Jr.

The eye examination included refraction, visual fields, extra-ocular muscle balance, red lens test, tonometry, depth perception, slit lamp, dark adaptation, and dynamic visual acuity.  Finally, a color photograph of the conjunctival and retinal vessels was made.  The otolaryngological tests included visual inspection, indirect laryngoseopy and nasopharyngoscopy, audiometric thresholds, speech discrimination, and labyrinth function by the standard caloric method.
 
Examination by a cardiologist included electrocardiograms and ballistocardiograms.  A tilt-table test was done, in conjunction with the physiology section, to acquire information on the stability of the pressor-reflex mechanisms and the effectiveness of vasomotor control by the autonomic nervous system.  (This test also may help in the detection of relative coronary insufficiency from electrocardiographic changes.)  The Lee and Gimlette procedure was employed by an expert to detect congenital abnormal openings between the right and left sides of the heart.

The neurological examination included testing the reflexes and coordination, determining the normalcy of cerebellar function, and determining proprioception and other senses.  Dr. L. D. Amick ascertained the conduction velocity of the right ulnar nerve between the elbow and the wrist.  An electroencephalogram was done, including a determination of the effects of hyperventilation.

Additional examination, were made by specialists where indicated. Proctosigmoidoscopy was performed by a surgeon.

Laboratory tests under the direction of Drs. T. L. Chiffelle and P. V. Van Schoonhoven included complete blood count and special hematology smear, hemoglobin, hematocrit, sedimentation rate, fasting blood sugar, cholesterol, blood grouping, sodium, potassium, carbon dioxide, chloride, urea clearance in blood and urine, blood urea nitrogen, catecholamine, protein-bound iodine, protein electrophoresis, blood volume (Sjostrand's carbon monoxide method), total body water determination by the tritium dilution method of Pinson and Langham (tracer dose of 1.5 millicuries of tritiated water used), bromstilphalein-dye liver function test, gastric analysis, urine analysis including colorimetric deterinination of 17-ketosteroids, throat cultures, stool examination, and sperm count.  The amount of potassium 40 was determined in the whole body counter at Los Alamos by Langham and Anderson.  The results of the laboratory tests in consolidated form are shown in table I.14

In the radiographic examinations, appreciable reduction in radiation exposure was accomplished by the use of supersensitive intensifying screens and shielding plus the use of ultrafast X-ray film.  Under the direction of Dr. J. W. Grossman, roentgenograms were made of the teeth, the sinuses, the thorax posteriorly-anteriorly in inspiration and expiration, and right laterally (searching especially for bullae), the esophagus, the stomach, the colon, and the lumbosacral spine, and cineradiograms were made of the heart (searching for preclinical evidence of arteriosclerosis).

Physical competence tests were administered by Dr. U. C. Luft to provide an estimate of the candidate's general physicial condition and cardiopulmonarycompetence.  Graded work was done on v. Dobeln's bicycle ergometer, increasing the load from 300 mkg/min to around 1,200 mkg/min under electrocardiographic monitoring for possible abnormalities at maximum effort.  The test proceeded until the heart rate reached 180 beats/min or until signs of approaching overload were evident.  The heart rate, blood pressure, respiratory volume, and respiratory gas exchange were measured each minute.  The oxygen consumption attained during the highest workload was the criterion of aerobic work capacity.  Each individual was rated with regard to standard values based on age, height, and weight.

Measurements were made of the total lung capacity and its various subdivisions by direct and indirect spirometry, and the efficiency of ventilation was determined by continuous recording of the dilution of nitrogen while the subject breathed 100 percent oxygen.  The timed vital capacity, maximal breathing capacity, and ventilatory response to light exercise (walking at 2 mph for 3 minutes) were determined.  With these tests it was possible to detect any restrictive or obstructive impairment and to estimate the efficiency of breathing at rest and during mild exercise.

Density of the body was determined by weighing the nude body in water after maximal inspiration followed by exhalation of a measured amount of air.  There was close correlation between the lean body mass calculated from the above results and from the K40 determinations.

A summary of the pertinent physiologic data is given in table II. 15

A final evaluation of each candidate in terms of physical, mental, was and social well-being was made at the conclusion of the week-long examinations.  The evaluation board was composed of the examining flight surgeons and a physiologist, all with extensive high-altitude and operational experience.  A summary of the finding  was prepared and, together with a copy of the machine record cards, was forwarded to the Aerospace Medical Laboratory at for Wright-Patterson Air Force Base.16


12.  Project Mercury: Man-in-Space Program of the NASA op. cit., p. 42.

13.  Lovelace et. al., op. cit. Also, additional information supplied by Drs. Lovelace and Schwichtenberg.

14.  Ibid.

15.  Ibid.

16.  Lovelace et al., op. cit., p. 680.  See also A. H. Schwichtenberg, D. D. on,  Flickinger, and W. R. Lovelace II, "Development and Use of Medical Machine Record Cards in Astronaut Selection," U.S. Armed Forces Med. J.,
 vol. 10, no. 11, Nov. 1959, p. 1324-1351.
 


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