Circulating neutrophil counts in the arterial blood exiting the lungs sampled from the thoracic aorta (•), the proximal venous blood entering the lungs sampled near the right atrium (○), and the distal venous blood sampled from the origin of the inferior vena cava near the union of the common iliac veins (□). The neutrophil counts increased by a similar degree in the proximal and distal venous blood by 7 minutes of infusion, and this increase persisted throughout the infusion. *Significantly greater than the neutrophil counts in the arterial blood, P < .05.