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) : Cruz-Jibaja,Julio C.

Report Date : JUN 1974

Pagination or Media Count : 28

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 ventilation/perfusion ratios (VA/Qc) with altitude exposure. On the other hand, HAS showed a more efficient gas exchange at altitude because of more even VA/Qc ratios and a larger diffusing capacity. (Modified author abstract)

Descriptors :   *High altitude, *Gas exchange(Biology), Stress(Physiology), Alveoli, Oxygen, Carbon dioxide, Exposure(Physiology), Diffusion, Tables(Data), Respiratory system, Lung, Hypoxia

Subject Categories : Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE