The influence of age on hemodynamics and the dose requirements of propofol and buprenorphine in total intravenous anesthesia
Tabuchi, Y.
Masui. Japanese Journal of Anesthesiology 50(1): 29-33
2001
ISSN/ISBN: 0021-4892 PMID: 11211745 Document Number: 534560
A retrospective study was performed to determine the influence of age on hemodynamics and awakening time in total intravenous anesthesia (TIVA) with propofol and buprenorphine for spinal surgery. Twenty patients (26-79 yr) were studied and allocated into following four groups by age: 26-49 yr,50-59 yr, 60-69 yr, and elderly 70-79 yr. All patients were premedicated with midazolam (2.5-5 mg) im. Anesthesia was induced (60-180 ml cntdot h-1) and maintained (20-60 ml cntdot h-1) with propofol infusion with 40% oxygen in air, added with vecuronium and one single dose of buprenorphine (0.08-0.2 mg; 1.37-2.63 mug cntdot kg-1) before incision. Mean arterial pressure was stable and did not differ in four groups. Heart rate was decreased (P<0.01) in the elderly group compared with the group younger than 50 yr. Bradycardia (below 50 beat cntdot min-1) occurred in 60% of the elderly group. An adequate dose of buprenorphine (mug) was proposed as : 208-1.8 X age (yr) + 0.3 X weight (kg) (r = 0.90, P < 0.01). The induction and maintenance rates (ml cntdot h-1) of propofol were decreased with age and increased with weight (P < 0.05). However, the maintenance dose of propofol (3.9-8.5 mg cntdot kg-1 cntdot h-1) did not correlate with age. Awakening time was prolonged (P < 0.05) in the elderly group (17.0+-7.2 min) as compared with the group of younger than 50 yr (8.0+-3.9 min). The three patients requiring postoperative analgesics were younger than 60 yr. This study suggests that we should reduce the dose of buprenorphine with age in TIVA using propofol. About 50% of the dose given to the patient younger than 50 yr was considered adequate in the elderly group.