Accession Number:

AD0786688

Title:

Alveolar Gas Exchange at Altitude.

Descriptive Note:

Final rept. 1 Jul 73-30 Jun 74,

Corporate Author:

UNIVERSIDAD PERUANA CAYETANO HEREDIA LIMA INSTITUTO DE INVESTIGACIONES DE LA ALTURA

Personal Author(s):

Report Date:

1974-06-01

Pagination or Media Count:

28.0

Abstract:

Apparent CO Diffusing capacity DLCO and alveolar-arterial O2 and CO2 tension differences have been measured at four levels of oxygenation. Seven sea level subjects SLS were studied at sea level SL and after 10 days of exposure to high altitude HA, 4350 m. Six high altitude subjects HAS were studied at HA. HAS showed larger DLCO than SLS but only breathing normal or low oxygen. On the other hand SLS did not modify their DLCO with altitude exposure, however they showed an increase in membrane diffusing capacity DM and a decrease in pulmonary capillary volume Vc. HAS showed these parameters similar to SLS at HA. A new criteria is presented to estimate O2 diffusing capacity DLO2 using the equation given by Staub, Bishop and Forster. No statistical significant difference was found between DLO2 and DLCO x 1.23 breathing normal or low oxygen either at SL or at HA. From the A-a oxygen and CO2 differences it is concluded that SLS showed more uneven distribution of ventilationperfusion ratios VAQc with altitude exposure. On the other hand, HAS showed a more efficient gas exchange at altitude because of more even VAQc ratios and a larger diffusing capacity. Modified author abstract

Subject Categories:

  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE