The Influence of Respiratory Movements upon the Circulating Leukocytes

1. The leukocyte content of venous and arterial blood of 17 subjects was studied repeatedly and frequently during respirations and the Valsalva and Muller maneuvers. The venous and arterial samples were drawn simultaneously and were obtained by direct puncture from freely-flowing peripheral veins or arteries or by catheterization from the right ventricle, pulmonary artery, hepatic vein, left ventricle or aorta.

2. During the Valsalva maneuver, the arterial leukocyte count decreased markedly with relatively little alteration in the simultaneous venous counts; upon release of the forced expiration both counts promptly regained the control level.

3. During the Muller maneuver, increases in both arterial and venous leukocyte counts occurred in one patient, while no significant effect was observed in venous samples in a second subject.

4. During inspiration the arterial leukocyte count fell and the simultaneous venous count rose with reciprocal changes upon expiration. These changes occurred whether the initial counts were elevated, normal or leukopenic.

5. The changes in leukocyte number of both arterial and venous blood during respiratory movements are not due to hemoconcentration or hemodilution and suggest a tidal ebb and flow of leukocytes into and from the pulmonary circulation of a significant degree.