[Effects of bacterial peritonitis on the low-pressure system in man]

The effective compliance (C) of the "low-pressure system" has been measured in ten patients with bacterial peritonitis by means of plotting pressure and volume on the first postoperative day (deltaV = 500 ml/10 min). The value of C is decreased in one group of patients, while it increases to as much as five times that of "normal patients" in the other. The cause might be a summation effect of hypovolemia, blood volume shift from intra- to extrathoracic space, and endotoxin reaction on the tone of vascular smooth muscle. The augmentation of the intravascular volume results in an increase of portal venous pressure, which is less than central venous pressure. Splanchnic pooling through increased vascular resistance does not appear.