│ │ │ 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 O_{2} 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 O_{2} 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 O_{2}
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.
Ro. experienced disturbances which in quality resembled the severe
disturbances in the 15 km. [49,200 ft.] sinking experiment, although the
degree of oxygen lack in this experiment was negligible in comparison to
the 15 km. [49,200 ft.] experiment, so that the idea of a combination of
pressure drop phenomena with the phenomena of oxygen lack is definitely
suggested.
_2. Descending experiments with O_{2} breathing_
Since obviously the utmost limits of these experiments had been reached
with the descending experiments from 15 km. [49,200 ft.] without oxygen
breathing, descending experiments with oxygen breathing were conducted
from greater heights.
In the experiments, the following experimental procedure was chosen:
ascent to 8 km. [26,300 ft.], remaining there 5 to 10 minutes with
oxygen breathing; then turning on the oxygen blower explosive
decompression to a predetermined altitude; 10 seconds waiting time
(experiments from 17 [55,800 ft.] and 18 km. [59,100 ft.], altitude
without waiting time) and descent at sinking speed. In order to imitate
the perpendicular body position as occurs in suspension in a parachute
harness, the experimental subjects had to stand during the experiments
since suspension was not possible in the small decompression chamber.
In the descending experiments from 15 km. [49,200 ft.] altitude there
was no altitude sickness or only a slight temporary kind. In the further
descending experiments, the following results were obtained (Table 4):
[page 19 of original]
Table 4.—Descending experiments with oxygen breathing
Unconsciousness │ From— │ Recovery of
after— │ │ consciousness after—
│ │
23 sec. = 15.75 km. │16 km. [52,500 ft.] │2 min. 35 sec. = 13.55
│ │km.
[51,660 ft.] │ │ [44,460 ft.]
10 sec. = 16.8 km. │17 km. [55,800 ft.] │3 min. 50 sec. = 13 km.
[55,120 ft.] │ │ [42,700 ft.]
7 sec. = 17.9 km. │18 km. [59,100 ft.] │10 min. 35 sec. = 8.5 km.
[58,740 ft.] │ │ [27,890 ft.]
Thus it was shown that unconsciousness developed relatively early in
spite of oxygen breathing, while the following convulsive stage ran its
course in a much less severe form than in the experiments without oxygen
breathing. Primarily spasmodic convulsions with only occasionally light
tonic convulsions developed. Breathing paralysis never set in and upon
recovery of consciousness the experimental subjects were again
completely in control of themselves. The markedly quick development of
unconsciousness was caused by the fact that the subjects were standing
during the experiments (to be considered in comparison with the
corresponding times in the falling experiments with oxygen breathing).
Descending experiments from still greater altitudes were not undertaken,
since in practice there is no need to escape from such altitudes with
open parachute and thus to expose oneself to the danger of severe
freezing.
_3. Falling experiments without oxygen_
Since the results of falling experiments from 12 km. altitude were known
from earlier experimentation and indeed descending experiments up to 15
km. [49,200 ft.] without oxygen had been conducted within the scope of
this work, falling experiments were begun at an altitude of 14 km.
[45,900 ft.], in order not to increase unnecessarily the number of
experiments.
[page 20 of original]
The ascent preceded by explosive decompression from 8 to 14 and 15 km.
altitude, in which the ascent to 8 km. was made with oxygen and the
explosive decompression with continuous flow, followed after 5 to 10
minutes waiting time. After the removal of the oxygen mask directly in
connection with the explosive decompression, five knee bends were made
during the waiting period of 10 seconds, then descent at free fall
speed. During the explosive decompression the oxygen supply was
interrupted from the outside. The results of these experiments were
(Table 5):