Differential lung ventilation

Abstract

Summary: The respiratory gas exchange of each lung was measured in dogs using a tracheal divider positioned with the aid of a bronchoscopic telescope. The proportions of tidal volume (VT), oxygen consumption (Vo2) and carbon dioxide output (Vco2) contributed by each lung were similar in the supine and lateral positions during spontaneous ventilation. During controlled ventilation the proportions were unchanged in the supine position but there was an increase in the proportion of VT, VO2 and VCO2 contributed by the upper lung in the lateral position. When ventilation to die lower lung was increased to produce equal end-tidal CO3 concentrations in bodi lungs the proportion of VT, VO2 and VCO2 contributed by each lung returned to values found in the supine position. © 1972 John Sherratt and Son Ltd.