Measurement of cardiac output during pregnancy: validation of Doppler technique and clinical observations in preeclampsia.

In 12 patients requiring pulmonary artery catheterization, cardiac output was measured using Doppler and thermodilution techniques. The Doppler technique accurately predicted measurements made by thermodilution (r = 0.91; P less than .001). Eighteen normal patients in the third trimester and 36 preeclamptics who had not been treated with medications other than magnesium sulfate were evaluated with Doppler alone. Of note was the heterogeneity among preeclamptics. Although their mean systemic vascular resistance was elevated, it ranged from 2256-648 dyne X sec X cm-5. Cardiac output ranged from 13.2-3.9 L/minute.