Prospective Doppler echocardiographic evaluation of pulmonary artery diastolic pressure in the medical intensive care unit.

To test the hypothesis that the noninvasive evaluation of pulmonary regurgitation can provide accurate estimates of pulmonary artery (PA) diastolic pressures and PA wedge pressures, Doppler echocardiographic studies were performed immediately before bedside PA catheterization in 29 medical intensive care unit patients. The characteristic color flow Doppler signal of pulmonary regurgitation was detected in 19 (66%) patients. In 17 of the 29 patients (59%), the gradient between the right ventricle and PA at end-diastole could be calculated from the pulsed-wave Doppler signal of pulmonary regurgitation using the simplified Bernoulli equation. Right atrial pressure was then estimated by examination of the jugular venous pulse or by electronic transduction of the pressure signal from a previously placed central venous catheter. A noninvasive estimate of PA diastolic pressure was made by adding the clinical estimate of right atrial pressure to the end-diastolic pressure gradient across the pulmonary valve. Pulmonary artery catheterization was then performed and stripchart recordings were interpreted by a physician who was unaware of the noninvasively-estimated PA diastolic pressure. The PA diastolic pressure estimated by Doppler echocardiography correlated closely with that found at catheterization (r = 0.94, mean absolute difference 3.3 mm Hg). The noninvasive estimate of PA diastolic pressure also correlated with the PA wedge pressure (r = 0.87, mean absolute difference 3.8 mm Hg). Therefore, in 59% of medical intensive care unit patients, Doppler echocardiographic evaluation of pulmonary regurgitation allowed accurate noninvasive estimation of PA diastolic pressure.