[Changes in the air-blood barrier of the lungs during the breathing of helium-oxygen gas mixtures].

The changes in the pulmonary air-blood barrier (ABB), occurring under the influence of helium-oxygen gaseous mixtures containing 11, 21 and 40% O2 in helium were studied in rats of two age groups (adult animals and 2-week-old cubs). The mean arithmetic and harmonic thickness of the ABB increased and its ultrastructure changed. It is suggested that helium exerts an indirect effect on the pulmonary ABB and that this effect does not depend on the O2 concentration in a gaseous mixture or on the animals' age. The electron microscopy data have demonstrated the endothelium of lung capillaries to be the most sensitive structural component as regards the action of helium-oxygen gaseous mixtures.