Pulmonary arterial pressure can be estimated by transesophageal pulsed doppler echocardiography

We examined whether pulmonary arterial pressure can be estimated on the basis of pulmonary arterial flow velocity determined via intraoperative pulsed Doppler transesophageal echocardiography (TEE) in 20 patients undergoing cardiac surgery. Standard pulmonary artery measurements were taken as well. Measurements were taken before sternotomy, after pericardiotomy, after cardiopulmonary bypass, and after sternum closure. The variables obtained by TEE included preejection period (PEP), acceleration time (AT), right ventricular ejection time (RVET), and R-R interval (RR). Five ratios were calculated as indices of pulmonary arterial pressure--PEP/AT, PEP/RVET, AT/RVET, PEP/ square root of RR, and AT/ square root of RR--and were compared with pulmonary artery catheterization findings, i.e., systolic pulmonary arterial pressure (sPAP), log sPAP, mean PAP (mPAP), and log mPAP. Before sternotomy, PEP/AT, PEP/ square root of RR, and AT/ square root of RR showed significant correlation with all pulmonary artery catheterization values. AT/RVET showed correlation with all pulmonary artery values except log mPAP. PEP/AT showed the closest correlation with sPAP (r = 0.771) and log sPAP (r = 0.789). PEP/AT also showed close correlation with mPAP (r = 0.764) and log mPAP (r = 0.777). Significant agreement between sPAP and mPAP values calculated from a regression equation and values measured via pulmonary artery catheter was observed by plotting the differences against the mean values of the two measurements. We therefore conclude that noninvasive estimation of pulmonary arterial pressure is feasible via intraoperative TEE when sternotomy is not involved.