A retrospective study was performed to evaluate the changes in hemodynamics and dose requirements in total intravenous anesthesia (TIVA) using propofol and buprenorphine without (Group S: spinal surgery (3-6 h), n = 8, 28-79 Y) or with (Group A: abdominal surgery (5-10 h), n = 15, 36-83 Y) epidural anesthesia. All patients were premedicated with midazolam i.m. (2-5 mg). Anesthesia was maintained with a single dose of buprenorphine (Group S: 1.9 +/- 0.4 micrograms.kg-1, Group A: 2.0 +/- 0.5 micrograms.kg-1), propofol infusion and vecuronium with 40% oxygen in air. Group A was supplemented with continuous epidural anesthesia using 2% mepivacaine. In Group A, mean arterial pressure (MAP) and heart rate remained stable after the start of surgery. However, in Group S, 2 hours after the start of surgery MAP increased (P < 0.05) and remained elevated (P < 0.05) at higher levels than those in Group A. The maintenance dose of propofol in Group A (4.0 +/- 1.1 mg.kg-1.h-1) was significantly smaller than in Group S (6.5 +/- 0.9 mg.kg-1.h-1). In both groups, infusion rates of propofol were unchanged from 1 hour after the start to the end of surgery. Infusion rates of mepivacaine (5.2 +/- 0.9 ml.h-1) were unchanged following the increase 2 hours after the start of surgery. Awakening times were within 25 min (Group S 11.3 +/- 7.2 min vs Group A 14.7 +/- 7.3 min). There was no awareness during anesthesia in either group. The results suggest that additional continuous epidural anesthesia in TIVA would be useful to reduce propofol dose, to stabilize hemodynamic state and to obtain rapid recovery in anesthesia of long duration.
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