Air Force the Official Service Journal - Air Force Historical Studies ...

Attached to a flyer's ear,
the Oximeter-Colorimeter
(right) deteets a c rit i
cal lack of owgen content in
blood and acti\'atcs \\':lrning
indicator (:II)o\'e) on the
plane's ius t ru m c n t panel.
strumcnt is attached to the airman's car as :1 huilr-in part of
the fhing helmet.
Employing a photo-electric cell, the appliance is designed
so that a red light or :l \\'arning horn is aeti\'ated when a
dangerom lack of ox\gen exists, The device is connected to
an indicator placed in convenient view of the airman.
The color of hlood changes from bright red to dark purple
as oxygen content decreases, This ch:mge can rcudilv be detected
in the thin tissne of the car b\ the colorimeter. Four
small lamps on one side of the e:n: shine throngh the ear
tIssue to generate a photo-electric cell plate on the opposite
side of the car.
As oxvgcn content decreases, the blood darkens, permitting
less light to pass through the car. Activation of the
photo-electric cell is thcrcbv decreased until the dcficicncv
is indicated on the \y,lrning ;ndieator in adequate time for ail
airman to corrcctlv adjust his owgen supplv.
Operation and adjustment of the device is simple. Before
t:lke-off, the car cup unit is placed in position. Current to
the lamps is turned on by a knob on the front of the indicator.
After about ten minutes, either before or after take-off,
when blood-flow through the ear has been stimulated by the
warmth of the attached lamps, the indicator is ready for
ad iustrn en t.
"'ith tile blood fully saturated with oxvgcn. the indicator
knob is turned un til a blue or green light will show until
owgen saturation of the subject's blood drops under S'i percent,
Belm\' this point, a red light appears to warn the airman
that protective measures must be taken. Imminent
col 1:1pse occurs when ox\-gen sa turn tion of blood drops to 'i'i
to () 'i pereen t.
The oximeter-colorimeter is particularly useful during high
altitude flight tests, It can be usccl also to indicate whether
wounded .rir evacuees arc reeei\ing an adequate ox\'gen
.-upplv,
The car unit h:IS proved practicable for anticipating blackouts
bv the decreased flo\\' of blood throngh the car nuder
the Gs resulting from violent aerial maneuvers of eentrifnge
tests.
An automatic valve, which wi]] increase the flow of owgcn
into the mask \yhen the indicator detects an oxygen deficicncv,
is being perfected to supplement the \yarning
system. "*
OCTOBER,1944
in;the~lC~'
as positive,p~~,
. .,'goggles' and helmet:.,
fitt~ as a' tWit . . "t0each~' < .to insure a lOOper ce~'
sure .seal•...A, ....