COMPARISON OF THE EFFECTS OF PROPOFOL AND ISOFLURANE ANESTHESIA ON RIGHT-VENTRICULAR FUNCTION AND SHUNT FRACTION DURING THORACIC-SURGERY

I.V. anaesthetic agents, including propofol, have not been shown to in hibit hypoxic pulmonary vasoconstriction (HPV). This may encourage the use of propofol in thoracic surgery where one lung ventilation (OLV) is required. We have compared the effects of maintaining anaesthesia w ith either isoflurane or propofol infusion on right ventricular functi on and shunt fraction. We studied 10 patients who received isoflurane and 12 who received propofol. When OLV commenced there was a greater r eduction in both mean cardiac index (3.2 (SEM 0.2) to 2.4 (0.1) litre min(-1) m(-2) for propofol, and 3.4 (0.2) to 3.3 (0.4) litre min(-1) m (-2) for isoflurane) and right Ventricular ejection fraction (0.45 (0. 03) to 0.37 (0.02) for propofol, and 0.48 (0.02) to 0.42 (0.02) for is oflurane) in patients who received propofol. Furthermore, these reduct ions were sustained for longer in the propofol group. However, propofo l was not associated with a significant increase in shunt fraction dur ing OLV, which increased threefold in patients who received isoflurane .