Physiological alterations in the pulmonary capillary bed at rest and during exercise. The effect of body position and trimethaphan camphorsulfonate

The reactivity of the pulmonary capillary bed during exercise as estimated by change in the pulmonary diffusing capacity (D l co ) has been shown to be dependent upon at least two separate mechanisms. The initial (0 to 10 second) D l co rise with exercise appears to be volume-pressure dependent and may be altered by mechanisms influencing these factors in the lungs. The later elevation of D l co with exercise was demonstrated to be primarily independent of the initial rise and uninfluenced by factors affecting peripheral venous return, that is body position and ganglionic blockade.