CONDUCT OF STUDY:
All patients received their previously prescribed cardiac medications before surgery in accordance with institutional practice. Anesthesia management was standard and typically consisted of intravenous propofol at induction, isoflurane in air-oxygen for maintenance and fentanyl for analgesia. Standard monitoring included electrocardiography, invasive arterial and central venous pressure, pulmonary artery catheter monitoring, pulse oximetry, capnography, temperature, urine output and transesophageal echocardiography was used in all patients.
The balloon was inflated for repeated measures of PCWP. Measurements were made at end-expiration. The zero pressure reference point was at the level of the mid-axillary line. After insertion of transesophageal echo probe, echocardiography measurements for three consecutive cardiac cycles were analysed and averaged by two independent and blinded observers. All the echo measurements were taken pre cardiopulmonary bypass at end expiration and during a stable period of hemodynamics. Simultaneously PCWP was recorded from PAC. A pulmonary capillary wedge pressure ≥ 15 mmHg was used to define elevated left atrial pressure10.