The pulmonary capillary blood flow (Qc) at rest and work measured simultaneously by 3 inert substances.

We have considered the opportunity of using some inert vapours (2-3 Dimethylbutane, 2 Methylpentane, n-Hexane) to measure the pulmonary capillary blood flow (Qc). The measurements were performed by means of a gas chromatograph connected with a mass spectrometer. The alpha values (Bunsen absorption coefficients) measured by a constant pressure method (multiple equilibration methods) were reported. Qc was measured in 14 healthy subjects at rest and in 5 subjects during exercise (25 and 50 watt by means of a cyclo ergometer, steady state test) (rebreathing method). The method used allow multiple measurements of Qc during the same exercise test.