With the use of peripheral and pulmonary arterial catheters, the peripartum hemodynamic patterns of 10 patients with severe preeclampsia were studied. At the time of line placement, our results demonstrated elevated cardiac outputs (9.3 +/- 1.3 L/min), high systemic vascular resistances (1,042 +/- 160 dynes . sec . cm-5), and hyperdynamic ventricular function. Immediately post partum (less than 30 minutes), a transient decline in left ventricular function in association with a rise in central venous and wedge pressures was observed. By 1 hour after delivery, ventricular function had returned to its hyperdynamic state. Swan-Ganz catheterization and cardiac output data were most helpful in the monitoring of patients with severe preeclampsia. Ventricular function in these patients appears to operate in the hyperdynamic zone or a "normal" ventricular function zone that is different from that in the nonpregnant patient. At the same time, as shown by our data and a review of the literature, severe preeclampsia appears to be a continuum, as determined by cardiac output and systemic vascular resistance measurements, which range from a high-output--low-resistance system to a low-output--high-resistance one. Therefore, in the evaluation of the patient with severe preeclampsia, a complete hemodynamic profile would be helpful in determining the "phase" of the disease and the status of ventricular function. This would be useful information with which one could theoretically direct therapy in a more precise fashion.