Atraumatic measuring of pulmonary capillary blood flow in dogs.

Pulmonary capillary blood flow (Qc) was measured by a nitrous oxide uptake technique using a capacitance-plethysmograph to measure pulmonary volume changes. One hundred and four paired Qc and total cardiac outputs (Qt) were measured in 13 normal mongrel dogs. The mean Qc was 0.101 +/- 0.020 1-min -1-kg-1 while the mean Qt, measured by dye dilution, was 0.117 +/- 0.025 1-min-1-kg-1. This technique minimizes subject trauma and provides a method for repeated pulmonary capillary blood flow determinations in acute or chronic studies.