Cardiovascular Effects of Increasing Doses of Norepinephrine in Healthy Isoflurane-Anesthetized New Zealand White Rabbits
Profound decreases in blood pressure occurs in anesthetized rabbits. Norepinephrine (NE) is a potent vasoconstrictor and inotrope, used to treat hypotension in multiple species; however, evidence of its actions in rabbits is limited. This thesis characterizes the cardiovascular effects of increasing doses of NE in healthy isoflurane-anesthetized New Zealand White rabbits. Nine female-spayed New Zealand White rabbits were premedicated with buprenorphine and midazolam and anesthesia was induced with propofol. Once intubated, they were maintained on isoflurane at 1.1 times MAC to establish a low arterial pressure baseline. Three increasing doses of NE (0.1, 0.5 and 1.0 μg kg-1 min-1) were given for 10 minutes. Infusion rates of 0.5 and 1 μg kg-1 min-1 resulted in significant dose-dependent increases in mean arterial pressure and stroke volume. These results suggest NE use in rabbits at rates of 0.5 and 1 μg kg-1 min-1 are appropriate to increase arterial pressures during isoflurane anesthesia.