| Clear | |||
| 15 km. | Unconsciousness | Subconscious awakening | consciousness |
| [47,200 ft.] | after— | movements | at 0 km. |
| Suspended | 16″ = 14.7 km. | 20½′ = 1.8 km. | |
| [48,220 ft.]. | [5,910 ft.]. | 18′-90′ | |
| Lying | 20″ = 14.6 km. | 14′ = 5 km. | 15′-80′ |
| [47,890 ft.]. | [16,400 ft.] |
Unconsciousness after discontinuation of oxygen occurs following a short motor restlessness with severe altitude sickness, whereupon light spasmodic and then very severe tonic convulsions follow in a condition of complete unconsciousness. These tonic convulsions lasting virtually a minute are followed rather suddenly by a phase of complete
[page 16 of original]
flacidity with a drop in breathing rate and transition to convulsive breathing with 3 to 4 breaths per minute until complete cessation of breathing of 45 seconds duration (post-hypoxemic pseudo-death—Lutz). Then follows a period of improvement in breathing, until the first subconsciousness movements announce the gradual recovery of consciousness, during which, nevertheless, the higher mental functions are temporarily entirely absent. Further recovery proceeds slowly during the course of the following ½ to 1½ hours as may be seen from the above case record. During the time of complete unconsciousness, there was defecation and urination in the case of most subjects, increased salivation and, in some cases, vomiting.
Here we obviously have the conditions which Lutz and Wendt in their animal experimentation which is referred to in greater detail later found in falling experimentation with O2 breathing and designated as “post-hypoxemic twilight state” (“Posthypoxaemischen Daemmerzustand”) since we are dealing with a slow recovery of consciousness, especially also in view of the mental behavior of the experimental subjects. The post hypoxemic pseudo-death observed by Wendt and Lutz was not found in any experiments in the form which they had observed. The severe condition described above we could designate as hypoxemic pseudo-death only because it was limited to the period of the most severe O2 lack (on the average, between 13.3 and 12.3 km.).
In spite of the relatively large number of experiments, the actual cause of the severe mental disturbances and bodily failures (paralysis, blindness, etc.) attendant upon post-hypoxemic twilight state remains something of a riddle. It appeared often as though the phenomena of pressure drop sickness had combined with the results of severe oxygen lack. In this connection, the subjective accounts made by the authors in two experiments each were interesting. In the case of Ro. during a half hour stay at 12 km. [39,400 ft.] with oxygen,
[page 17 of original]
only the usual pains attendant with bends occurred. In a further experiment with a stay of 40 minutes duration at an altitude of between 13 [42,650 ft.] and 13.5 km. [44,290 ft.] there developed very gradually a condition of weakness, combined with a peculiar headache, which then led to a considerable slackening of strength in the arms and hands. As a result of this, Ro. could no longer hold the breathing mouthpiece (for special reasons in these experiments, Ro. had to breathe with a mouthpiece and nose clamp) so that it slid out of his mouth. All these phenomena were still clearly observed by Ro. Ra. returned the mouthpiece to Ro. However at this point Ro. failed rather suddenly with paleness, strong cyanosis of the lips and complete unconsciousness. After Ro. had regained clear consciousness through descent and sufficient O2 breathing, he determined the existence in himself of a complete paralysis of the legs, weakness of the arms and severe disturbances of vision. These serious disturbances developed although the time of oxygen lack and unconsciousness had lasted only about 5 seconds. Following descent soon after this to 0 km., the paralysis of the legs continued for about 5 minutes more and the very severe visual disturbances only cleared up after 2 hours. While this episode of Ro.’s occurred in an experiment at a special altitude, the disturbances occurred in Ra. at an altitude of between 12 [39,400 ft.] and 13 km. [42,700 ft.] while he was breathing sufficient oxygen with a mask and continuous flow into the circuit. After 10 minutes stay at this altitude, pains began on the right side with a spastic paralytic condition of the right leg which increased continually as though Ra.’s whole right side were being crushed between two presses. At the same time there were most severe headaches as though the skull were being burst apart. The pains became continually more severe so that at last the discontinuation of the experiment became necessary. The pains disappeared when ground level was reached while the disturbances of the right leg continued about 5 minutes more. Shortly before the
[page 18 of original]
second experiment, Ra. took two tablets of “Antineuralgica” (a coal tar derivative) and two tablets of pervitin. In the course of the experiments there occurred only light pains in the right arm and leg, moderate headaches, but a very severe uncontrollable urge to cough, actually less severe difficulties than in the foregoing experiment, although this one was made at 1,000 m. [3,280 ft.] higher.