Effect of propofol infusion at different rate on liver blood flow and oxygen metabolism in rabbit / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of propofol infusion on hepatic blood flow (HBF) and oxygen delivery and consumption in rabbit. Methods Thirty adult male rabbits weighing 1.6-2.4 kg were randomly allocated into 3 groups group I high dose propofol (HP) ( n = 11); group II low dose propofol (LP) (n = 10) and group III control group (C) ( n = 9). The rabbits were anesthetized with intravenous 3 % pentobarbital 45 mg ?kg-1 and mechanically ventilated (VT = 10 ml?kg-1 RR = 40 bpm, IE= 12) after tracheal intubation. ECG, urinary output and rectal temperature were continuously monitored. Portal vein and hepatic artery were dissected and exposed for measurement of blood flow using electromagnetic flowmeter. Catheters were inserted into carotid artery, portal vein and hepatic vein via the mesenteric vein and right femoral vein for collection of blood samples. After the circulation was stabilized for 30 min, propofol infusion was started at a rate of 1.2 mg ? kg-1 ? min-1 ( HP) or 0.4 mg?kg-1 ?min-1(LP). In control group normal saline was infused instead of propofol. Portal venous and hepatic arterial blood flow were continuously measured. Blood samples were obtained from carotid artery, portal vein and hepatic vein before ( baseline) and at 30, 50, 70 and 90 min of propofol infusion for determination of Hb, SO2, PO2 and PCO2. The hepatic O2 delivery (DO2 ) and consumption (VO2 ) were calculated. Results The three groups were comparable with respect to body weight, duration of operation, the volume of fluid infused and blood loss and urinary output. HBF was significantly higher at 30-90 min of propofol infusion in HP group than in C group, meanwhile DO2 and VO2 in HP group were significantly higher during propofol infusion than the baseline value before infusion and those in C group. However, there was no significant difference in DO2/VO2 ratio between HP and C group. Conclusion High dose propofol infusion improves liver blood flow and O2 delivery but it also increases hepatic O2 consumption. However the balance between hepatic O2 supply/demand remains unchanged.