AIR ABORT, AIRCRAFT 132, MISSION 68T090, 3 APRIL 1968

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP71B00590R000100050009-2
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 8
• Document Creation Date: November 17, 2016
• Document Release Date: March 15, 2000
• Sequence Number: 9
• Publication Date: April 12, 1968
• Content Type: MFR

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OXC-0314-68
Copy- -Of
12 April 1968
SUBJECT Air Abort, Aircraft 132, Mission 68T090,
25X1A 3 April 1968
REFERENCE : 4 April 1968
25X1A
1. The undersigned has studied the available information
regarding the referenced incident involving on
3 April 1968, and has compiled the attached review. is 25X1A
review includes available information regarding both the
recent incident and background information regarding
previous cases of suspected decompression sickness. Also
included is a brief review of information and case histories
from the literature, a summary of this case, and recommendations.
2. The attached review represents the opinion of the
undersigned and is presented as such for the record.
25X1A
CAPT. USAF BSC
ASD/R&D/OSA
Attachment - 1
As stated above 25X1A
ASD/R&D/OSA :sjs (12 April 1968)
Distribution:
orig - ASD/R&D/OSA w/att
2 - D/R&D/OSA w/att
3 - D/SA w/att
4 - D/O/OSA w/att
5 - OXC/O/OSA w/att
6 - PD/Compt/OSA w/att (Gen..Flicking
7 - ASD/R&D/OSA (Chrono) w/att
8 - RB/OSA w/att
OXCART 25X1A
SECRET
j1 ro c q6H efeaS 000/ ft 29: CIA- B 05' 0
25X1A
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A CASE FOR THE "CHOKES"
1. Recent Incident; 3 April 1968:
A. Subject had been airborne for 57 minutes, breathing
100% oxygen at a maximum cabin altitude of 26,000 feet when
he experienced sudden onset of left substernal pain with
radiation to the left anterior and lower rib cage. He did
not feel short of breath, but was unable to take deep breaths
due to increase in chest pain. The subject reported symp-
toms and was instructed to inflate his pressure suit manually
which he did. There was no immediate relief of symptoms, but
apparently there was a diminution of the pain some minutes
after the pressure suit was inflated. The subject returned
to base and was on the ground approximately 32 minutes after
onset of symptoms. Subject was examined at that time with
no abnormalities except symptoms of pain which persisted for
approximately 30 minutes before complete relief.
B. While the attending physician noted no other signs,
the base Commanding Officer, who was also present, stated the
subject was pale for an extended period of time after reaching
the ground. The subject stated, during follow-up examinations,
that he was very anxious/apprehensive during the incident--
beyond what he felt the symptoms warranted--and felt that he
must descend as soon as possible.
C. X-rays, lab studies and physical examinations on the
day and the following day were normal. WBC count was eleva-
ted, with normal differential.
D. Information given by the subject and attending
technicians indicated that 100% oxygen was breathed without
interruption for 40 to 50 minutes prior to aircraft take-off.
All personal equipment functioned satisfactorily and the
oxygen supply was free from contamination.
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E. Two days after the incident the subject was taken
to 26,000 feet simulated altitude in a chamber without any
preflight denitrogenation. He was held at that altitude,
breathing 100% oxygen, for approximately 10 minutes before
return to ground level. No problems were encountered.
2. Background Information on this Individual:
A. In June 1967 subject experienced gradual onset of
mild to moderate deep discomfort in right knee joint, which
was aggravated by rubbing or movement of the leg. Total
duration of symptoms was approximately 5 to 10 minutes and
was associated with a mild parasthesia of the skin over
dorsum of back. The symptoms occurred at a cabin altitude
of 26,000 feet after approximately 3J hours exposure. Ground
level prebreathing of 100% oxygen was accomplished for
approximately 40.minutes prior to take-off. He had opened
his facepiece for a short period after approximately 22 to
3 hours of exposure at this altitude. The symptoms responded
rapidly to manual pressure suit inflation to 1.0 to 1.5 psi
above cockpit pressure.
B. This subject also relates a single previous episode
of bends in the right elbow in 1963 during an altitude chamber
indoctrination in the full pressure suit. History from
chamber flight records is as follows: 19 March 1963 - After
3 hours 25 minutes at 26,000 feet, the subject felt faint
symptoms of bends in left elbow. Then it became a dull
sensation. Then throbbing with heart beat in the joint.
Chamber altitude was lowered to 10,000 feet after 20 minutes
and the pain immediately cleared up. The subject was brought
back to 26,000 with no change. Gradually the feeling changed
from sore to hurt. At this point the flight was aborted
after 4 hours 45 minutes to preclude possibility of the bends
recurring. Odd sensation on ground. OK to go (another
chamber flight) day after tomorrow. Stomach was upset at
start of run--subject had sausages for breakfast. Subject
.drank water during run (at 10,000 feet) and stomach was OK.
Subject had headache after run. Note.: Apparently 1 hour of
prebreathing 100% oxygen was performed on all altitude chamber
runs conducted during this period. However at least 5
individuals reported bends during one of their 3 to 4 chamber
runs. This subject and one other (in same time period, ie,
18-22 March 1963) had bends which caused flight to be
terminated. Three other cases, bends were tolerated or
transient.
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CPYRGHT
C. The only other history of significance is that the
subject has an old, asymptomatic athletic injury of the right
knee, incurred in 1949.
D. One other comment of note pertains to this individ-
ual. Various individuals in the Life Support Section have
stated to this reviewer that this subject, as compared with
all others, objects to prebreathing the most and generally
refuses to engage in denitrogenation prior to transfer to
the aircraft. How accurate the reported denitrogenation
times are for the most recent or even the past episodes is
a matter of question in light of this individual's attitude
and behavior regarding prebreathing.
3. Review of Information and Similar Cases from the Literature:
A. Symptomatology of Chokes: from Dysbarism, Aeromedical
Review 1-64 USAF SAM, Feb. by H.F. Adler.
Mere are
rue chokes. The severity of symptoms is as variable as in
he case of bends. The symptoms may be intermittent but have
tendency to progress.
(1) Substernal Distress which may vary from a dry
sensation in the chest to a burning, gnawing, sometimes
lancinating substernal pain which does not, in the usual
case, radiate to other regions. There may only be a
sensation of fullness, sense of constriction, tightness,
or oppression in the chest. The sensation has been
compared sometimes with a burning or rawness similar to
that encountered during running or heavy exercise in
cold weather. The symptoms may persist for some time
even after return to ground level, and residual chest
soreness may persist for hours or days.
(2) Symptom of Cough varies from a desire to cough,
which is controllable to a distressing paroxysmal cough
which interferes with respiration and probably with
cardiovascular physiology. Cough is usually rasping,
hacking, and nonproductive.
(3) Aggrevation of Pain/Cough: At altitude, the
substernal distress and cough are aggravated to a marked
degree by attempts to perform physical exercise. Even
attempts to take a deep breath cause a marked increase
in chest symptoms and/or an intense desire to cough.
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(4) Difficulty in Breathing is accompanied by a
sense of suffocation. and apprehension. Breathing is
likely to be rapid and shallow because of voluntary
attempts to avoid painful deep breaths.
(5) Other Symptoms: With severe chokes cyanosis
may be noted, but generally there is an intense pallor
in severe chokes which may mask any cyanotic color.
Along with pallor there can be considerable weakness
and perspiration. Faintness and syncope are not
uncommon in moderate to severe chokes. A marked feeling
of fatigue after all other symptoms may have disappeared
is a common experience during the period following
return to normal atmospheric pressures.
B. Review of Cases:
(1) Aerospace Med, Dec 1966, Treatment of Altitude
Dysbarism with Oxygen Under High Pressure - Report of
Three Cases, McIver and Kronenberg, pages 1266 to 1269.
a. Case 1. 29 year old white male research
subject. 1 hours prebreathing 100% 02 at 14.5 psi.
35,000.feet for 1 hour on 100% 02 - complained of
mild shortness of breath during exercise associated
with mild upper anterior chest pain which was worse
on deep inspiration. Symptoms decreased until
approximately 1 hour after onset when he reported
feeling cold and clammy. Descended-to 11,500 feet
and examination revealed pulse rate of 100 with an
occasional missed beat and moderate cyanosis of
nail beds. After 52 hours at ground level (pulse
rate and cyanosis remained) sudden onset of nausea,
generalized weakness followed by loss of conscious-
ness and grandmal seizure. Five hours after onset
of first symptoms WBC was 18,300 and was 17,700
after 81 hours. Treated in Hyperbaric chamber.
b. Case 2. 36 year old white male research
subject. Ty hours 100% 02 at 12.7 psi (4,000 feet).
After 1 hour at 35,000 feet subject had transient
flash of pain at the base of left scapula. Three
minutes later he noted sensation of needles all
over his body and a cold flash across the anterior
chest. Descent started with all symptoms gone at
24,750 feet. Descent stopped at 11,500 feet (still
on 100% oxygen). After 14 minutes at this altitude
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patient noted mild right substernal chest pain,
but did not report this for an additional 20
minutes. At this point the pain was severe,
burning in character and accentuated by deep
breathing. Coughing was a prominent symptom.
Descent was made to ground level. Treated in
hyperbaric chamber. WBC at 2 hours after onset
of symptoms was 7,100 with no further follow-ups.
c. Case 3. 35 year old white male research
subject. 3 hours prebreathing 100% 02 at 14.5 psi.
After 2 hours 33 minutes at 35,000 feet, observers
noted the patient's facial expression showed dis-
comfort. Upon questioning he stated he was unable
to catch his breath and was somewhat faint and
dizzy. Also noted paroxysms of coughing and
substernal pain on deep inspiration. Chamber
descended to G.L. At G.L. subject's faintness and
dizziness were gone but chest discomfort remained.
Was extremely pale, anxious and somewhat cyanotic
with blood pressure of 90/50 and pulse 56 (normal
blood pressure was 120/70, pulse 56).' Was treated
in hyperbaric chamber. WBC at 3 hours after onset
was 8,500 and was 5,700 after 20 hours.
(2) United States Armed Forces Medical Journal,
Vol. X, pages 1 to 15, Jan 1959: Severe Dysbarism in
Actual and Simulated Flight, A Follow-Up Study of Five
Cases, Berry and King.
a. Case 4. 35 year old senior pilot, in-
flight circulatory reaction after exposure to
29,000 feet for 20 minutes with symptoms of bends,
chokes, fatigue and skin reaction (delayed).
Moderately obese 71f, 183 lbs.
T-33 back seat pilot. 25 minutes after take-off
at altitude of 35,000 feet (26,000 feet cabin
altitude) began to experience pain in right lower
costal area. Thought it was "gas"--climb continued
to 37, eet. Then had pain in the left anterior
axillary fold and above left knee and right elbow.
Then had tingling in arms and hands. Took a deep
breath of 100% 02 and within a few seconds developed
a severe, dry, hacking cough. Descent to 30,000
with relief of respiratory difficulty but persist-
ence of other pains. Descent to 13,000 feet with
relief of all symptoms. After landing he felt
unusually tired and had some residual soreness.
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The next morning the patient noted nonpruritic,
hive-like, red splotches in the same areas where
he had previously experienced pain.
4. Notes on Seriousness of Chokes:
A. Neurocirculatory Collapse at Altitude by H.F. Adler,
Special Project, USA SAM, June 1950.
(1) In an estimated 1,000,000 man exposures in low
pressure chambers to 30,000 feet or above there have
been about 400 collapse cases of which about 150 could
be considered serious. Of the latter cases, seven were
fatal.
(2) 89% of the collapse cases are associated with
bends, chokes, abdominal symptoms or various combina-
tions of these three conditions.
(3) Of 314 collapse cases, 16.8% had bends and
chokes as associated symptoms and 14.6% had chokes only
as an acgocio+t9d symptom
CPYRGHT
B. Dysbarism, Aeromedical Review 1-64, USAF SAM, Feb
1964 by H.F. Adler.
(1) True chokes at altitude should be regarded as
a dangerous symptom, the gravity or potential seriousness'
of which requires immediate recognition and prompt action
by the trained individuals in attendance. No case of
true chokes should be regarded lightly and all grades are
potentially dangerous, even after the individual returns
to normal barometric pressures.
5. Summary:
While the subject did not demonstrate all the typical
symptoms of chokes, his symptoms were very closely related.
In light of the negative laboratory, X-ray and physical
examination results, and his previous experiences with decom-
pression sickness, this reviewer is inclined to believe that
the subject experienced a moderate case of decompression
sickness, specifically the chokes. The diagnosis of inter-
costal muscle spasm officially recorded cannot be disproven,
nor can it be completely verified. Neither can the opinion
of this reviewer be backed up by purely scientific data
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regarding individual susceptibility except to state that the
problem of differences in susceptibility is recognized, ie,
to quote Adler in Dysbarism, "Differences in susceptibility
to bends between different individuals, and even in the same
individual on separate exposures, are often very marked.
6. Recommendations:
It has never been completely proven that there are
"decompression sickness-prone" individuals, while it has been
shown that decompression sickness can be produced under the
right conditions in almost, if not all, individuals. There-
fore it is not logical to consider grounding the individual
involved at this time. USAF medical regulations concerned
with grounding of pilots for incidents of decompression
sickness, require permanent grounding only when neurological
symptoms are involved. Short of such an occurrence there is
no foundation for grounding this individual.
Decompression sickness can be prevented by adequate
denitrogenation (ie, prebreathing 100% oxygen prior to flight)
and as it pertains to this individual a stricter policy or
procedure should be instituted in view of his experiences to
date and the specific mission-related requirements involved.
That is, because of this subject's past encounters with
decompression sickness, loss of this individual on a future
operational or training mission would be presumed, if other
positive evidence was lacking, to have been caused by severe
decompression sickness. Therefore for maximum protection of
this individual and the program, a minimum of one full hour
of uninterrupted prebreathing of 1007o oxygen prior to ake-off
is the recommended denitrogenation regimen for all flights
regardless of duration. It must be insured that the procedure
is to have the subject suited and "on-the-hose" a minimum of
one hour before the earliest anticipated take-off time.
If this recommendation is followed and the individual
encounters another episode of decompression sickness in the
future, re-evaluation by all. knowledgeable representatives
will be required before a new course of action can be
recommended.
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