Minute distance obtained from pulmonary venous flow velocity using transesophageal pulsed Doppler echocardiography is related to cardiac output during cardiovascular surgery

Purpose. We studied the relationship between minute distance calculated from pulmonary venous flow (PVF) velocity tracing and cardiac output (CO)measured with thermodilution method in patients undergoing cardiovascular surgery. Methods. In 32 patients undergoing cardiovascular surgery, simultaneous measurements of hemodynamics including CO and transesophageal pulsed Doppler signals of PVF velocity were performed before and after surgical repair. Minute distance was calculated as the product of the heart rate and the sum of time-velocity integrals of PVF. Results. The minute distance after surgical intervention increased from 1121 ± 347 cm・sec-1to 1764 ± 538 cm・sec-1 (plt0.001 mean ± SD), while CO increased after surgical intervention from3.5 ± 0.9 L・min-1 to 5.3 ± 1.1 L・min-1. Simple linear regression analysis showed that minute distance was related with CO before and after surgical intervention (r=0.81 and r=0.76, respectively). The changes in minute distance were also related with those in CO (r=0.80). Conclusion. The present study demonstrated that minute distance obtained from the pulsed Doppler tracings of PVF velocity was related with CO during cardiovascular surgery in adults. These results suggest that the changes in CO could be estimated from minute distance in pulmonary vein.