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.