[CO diffusing capacity during continuous negative extra-thoracic pressure].

Eight healthy males were studied to compare CO diffusing capacity (DLCO) during spontaneous breathing with that during continuous negative extra-thoracic pressure (CNETP). Mean DLCO was 33.0 +/- 5.1 ml.min-1.mmHg-1 during spontaneous breathing and 33.5 +/- 4.5 ml.min-1.mmHg-1 during CNETP with an end-expiratory negative extra-thoracic pressure (EENETP) of -20 cmH2O, and there was no significant difference between them (P less than 0.05). Pulmonary capillary blood volume, which was measured only in a male, was 76.7 ml during spontaneous breathing and 80.5 ml during CNETP. This change dose not seem to be significant. The results suggest that the effect of pulmonary diffusing capacity changes during EENETP on improvement of oxygenation may not be significant.