Effect of breathing an oxygen-helium mixture under positive pressure on biochemical parameters.

In 35 subjects the effect of breathing an oxygen-helium mixture or oxygen during 10 minutes under positive pressure of 40 hPa was studied. Immediately before positive-pressure breathing, in the last minute of this breathing, and 30 minutes after its and blood samples were taken for investigations. Positive-pressure breathing caused in both groups a rise-in the haematocrit value, total protein, albumin and glucose levels. The level of lactic acid rose during breathing oxygen by 74% and that of pyruvic acid increased by 44%, while during the use of the oxygen-helium mixture both these compounds failed to rise during positive-pressure breathing and 30 minutes after its completion.