Hemodynamic measurements in preeclampsia: preliminary observations.

Ten patients with preeclampsia were monitored with a Swan-Ganz thermodilution catheter before the start of treatment. Reference data were obtained by right-heart catheterization in four normal pregnant women. In the preeclamptic group the effects of volume expansion and vasodilatation were studied. All patients showed a low cardiac index, low pulmonary capillary wedge pressure, and a high systemic vascular resistance. Following volume expansion the pulmonary capillary wedge pressure and cardiac index rose to normal pregnant values whereas blood pressure showed no significant change and systemic vascular resistance decreased, but normal pregnant values were not obtained. Vasodilatation with dihydralazine resulted in a further decrease in systemic vascular resistance, a fall in blood pressure accompanied by a further increase in cardiac index with a stable pulmonary capillary wedge pressure. It is concluded that pregnant women with preeclampsia are unable to cope with a circulating volume necessary to maintain a cardiac index and ventricular filling pressure which is considered to be physiologic in normal pregnancy. In preeclampsia the capacity for vasodilatation is inadequate.