Kp. Vohra et Ra. Klocke, DETECTION AND CORRECTION OF HYPOXEMIA ASSOCIATED WITH AIR-TRAVEL, The American review of respiratory disease, 148(5), 1993, pp. 1215-1219
Hypoxemia occurs during air travel because the pressure in aircraft ca
bins is not maintained equal to barometric pressure at sea level. Iden
tification of patients who will develop significant arterial hypoxemia
is most conveniently achieved by exposing these individuals to inspir
ed oxygen tensions similar to those experienced during air travel. We
utilized commercial Venturi devices with nitrogen as a source gas to l
ower inspired oxygen tensions (114 and 99 mm Hg) to simulate exposure
to altitude (6,700 and 10,000 feet) that occurs with air travel. Oxyge
n was administered by nasal cannulas to correct the induced hypoxemia.
Eleven normal subjects had baseline oxygen saturations of 97.3% as de
termined by ear oximetry. Exposure to reduced oxygen tensions for 20 m
in using 35 and 40% Venturi devices caused minimal O-2 desaturation (9
4.8 and 93.8%, respectively). Mean baseline arterial oxygen saturation
was 93.2% in 11 patients with chronic obstructive lung disease. Oxyge
n saturation fell to 89.5 and 87.5%, respectively, with exposure to th
e two levels of reduced oxygen tensions. Hypoxemia was corrected with
administration of O-2 by nasal cannulas at rates of 1.2 and 1.5 L/min,
respectively. We conclude that individual patients can be evaluated c
onveniently for possible development of hypoxemia associated with air
travel using available Venturi devices. This approach also permits det
ermination of the oxygen therapy needed to correct hypoxemia.