The purpose of this study was to assess the accuracy of a quantitative, range-gated, two-dimensional Doppler echocardiography method for measurement of blood flow in the fetal lamb descending aorta. Comparison was made between this method and measurements determined by an electromagnetic flowmeter placed directly on the aorta in the chest of the fetus. Stroke volume was manipulated acutely either by the removal of blood, the addition of fluid by injection, or by pharmacologic means. During each procedure, descending aortic blood flow was estimated by the Doppler ultrasonography method and compared to the flowmeter recording. The size of the lumen of the aorta determined by echocardiography was correlated with direct measurement during surgery and at autopsy. A total of 359 flow measurements were obtained in 15 fetuses. Doppler ultrasonographic flow studies and electromagnetic flowmeter measurements were found to be highly correlated (r = 0.93). The study demonstrates the accuracy and reliability of the two-dimensional pulsed Doppler echocardiography method for measurement of blood flow in the descending aorta in the fetal lamb.
- Pulsed Doppler echocardiography
- fetal lamb