EFFECT ON GAS MIXING OF A HE-O2 MIXTURE IN CHRONIC OBSTRUCTIVE LUNG-DISEASES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 15  (5) , 1053-1068
Abstract
To estimate the role of gaseous diffusion in the mixing disorders of chronic obstructive lung diseases (COLD) the effect of breathing a gas mixture lighter than air was studied. Patients [24] with severe airflow obstruction were tested by breathing in a random order 2 different mixtures with the same PO2: air and He-O2 (heliox) for 20 min. Ventilation was monitored during the whole of each run; during the 2 last min arterial blood was sampled. While breathing heliox a slight, non-significant increase in ventilation was observed with a slight but statistically significant decrease of PaO2 [arterial O2 partial pressure] (P < 0.01), of PaCO2 [arterial CO2 partial pressure] (P < 0.05) and increase of pH (P < 0.01). Apparently there is a slight increase of distribution disorders with alveolar hyperventilation. To suggest stratification, improvement of diffusion due to low density should have been masked by other phenomena. The possible effects of ternary diffusion, increased viscous resistances and change of transfer factor were investigated. Such counter-effects were not found. Apparently stratification is not the major factor in distribution impairment in COLD.