Studies of colloid osmotic pressure in pregnancy-induced hypertension.

Pulmonary edema, although infrequently encountered, may cause death in severe cases of PIH. The mechanisms that account for edema in these instances are unclear. With a transducer-membrane system to directly measure serum COP, 22 patients with PIH were compared to 23 normal pregnant patients at term. In the PIH group the antepartum and postpartum COP values were significantly lower (17.9 and 13.7 mm Hg, respectively) than comparable values for the control group (22.0 and 17.2 mm Hg, respectively). Two patients in the PIH group in whom the antepartum COP values were 13.1 and 14.7 mm Hg exhibited clinical and radiographic evidence of pulmonary edema. Pulmonary artery wedge pressure (PAW) recorded in one patient with pulmonary edema was only moderately elevated to 18 mm Hg. We believe that serial COP determinations combined with pulmonary artery pressure monitoring may be helpful to guide fluid therapy in critically ill patients with PIH.