Hemodynamics of preeclampsia.
A review of the English literature reveals considerable disagreement regarding the cardiovascular hemodynamics of preeclampsia as measured by both noninvasive and invasive techniques. In the untreated patient, most of the data suggest the presence of low CO, low PCWP, and elevated SVR as compared to normotensive pregnancy. In contrast, in patients receiving treatment prior to the measurements, the majority of the data indicate the presence of normal to elevated CO, PCWP, and SVR. There is general agreement that plasma colloid oncotic pressure is markedly reduced in patients with severe disease, and this reduction is more dramatic in the postpartum period especially in those receiving excessive crystalloid therapy. As a result, these patients are at increased risk for pulmonary edema. Several studies recommended using plasma and plasma substitutes to correct the reduced plasma volume and PCWP prior to the use of vasodilator therapy in such pregnancies. This management requires the use of invasive hemodynamic monitoring, and its benefit is transient and not well established. Finally, the true cardiovascular hemodynamics of preeclampsia remain unknown.