Abstract
The effect of positive end-expiratory pressure (PEEP) on left and right ventricular diastolic filling dynamics was assessed by transmitral and transtricuspid flow patterns. Using transoesophageal Doppler echocardiography in fourteen ASA physical status 1 female patients, the following measurements were performed at baseline (0 cmH2O PEEP) and at 5, 10, 15, and 20 cmH2O PEEP: 1. peak velocity of early filling (peak E velocity), 2. peak velocity of atrial contraction (peak A velocity), 3. the ratio of the peak E to A velocity (peak E/A velocity ratio), 4. isovolumic relaxation time (IRT), 5. acceleration half-time (AHT), 6. deceleration half-time (DHT) of early filling, and 7. end-diastolic and end-systolic areas of both ventricles. Increasing PEEP progressively deceased peak E velocity of both ventricles. In contrast, peak A velocity did not change and the peak E/A velocity ratio decreased significantly with PEEP. IRT and AHTs remained unchanged, but DHTs of both ventricles increased following PEEP. End-diastolic and end-systolic areas of both ventricles decreased gradually and significantly with PEEP. It is concluded that PEEP was associated with decreased preload as well as reduced compliance of both ventricles, which was considered to contribute to the changes in diastolic ventricular filling.