ABSTRACT
BACKGROUND: Propofol is a good choice for elderly patents because it produces rapid onset and quick recovery with few side effects. Propofol produces dose-dependent cardiovascular depression. This effect is more pronounced in elderly patients during induction and can be minimized by a slow injection. The aim of this study was to determine the appropriate induction dose of propofol using a slower infusion rate for elderly patients to obtain desirable sedation and hypnotic conditions with minimal hemodynamic changes. METHODS: Thirty-nine patients aged over 70 years were assigned to receive a propofol infusion of either 1.5 mg/kg (n = 21, Group 1) or 2.0 mg/kg (n = 18, group 2). The infusion rate was 20 mg/kg/hr. The systolic and diastolic pressure, heart rate, BIS and modified observers assessment of the alertness/sedation scale (OAA/S) were measured before the induction (baseline), after the propofol infusion, as well as immediately, 3 and 5 minutes after intubation. RESULTS: The systolic pressure decreased significantly after the propofol infusion in both groups (group 1: 17%, group 2: 25%) but there were no significant differences between them. The BIS values after the propofol infusion and intubation were 67.1 +/- 12.6 and 62.3 +/- 12.7 in group 1, 49.6 +/- 11.1 and 51.7 +/- 11.7 in group 2, respectively which showed significant differences between the groups. CONCLUSIONS: When 2.0 mg/kg of propofol is administrated to elderly patients, a slower infusion rate is more appropriate for maintaining the desirable sedation and hypnotic conditions and cause no significant hemodynamic changes.
Subject(s)
Aged , Humans , Blood Pressure , Depression , Heart Rate , Hemodynamics , Intubation , PropofolABSTRACT
BACKGROUND: In case of inhalational anesthesia for cesarean section, there is a high risk of recall, and the bispectral index (BIS) is useful for measuring the depth of anesthesia. Sevoflurane has advantages in terms of rapid induction and emergence from anesthesia. This study was designed to determine optimal end-tidal concentrations of sevoflurane and BIS values during cesarean section. METHODS: We randomized 30 patients scheduled for elective cesarean section to receive end-tidal sevoflurane 0.8 vol% (Group 1, n = 10), end-tidal sevoflurane 1.0 vol% (Group 2, n = 10), or end-tidal sevoflurane 1.2 vol% (Group 3, n = 10) in a 50% nitrous oxide oxygen mixture until delivery. Each group was assessed for BIS, blood pressure, and heart rate at preinduction, intubation, and at 2 and 4 minutes after intubation and delivery. Neonatal effect was assessed by Apgar score at 1and 5 minutes and blood gas analysis of the umbilical artery and vein. RESULTS: The BIS of group 3 was lower than 70 on each occasion and most of BISs of the other groups wear also more than 70. The BIS of group 3 was lower than that of group 2 at 4 min after intubation and the BIS of group 3 was lower than that of group 1 at delivery (P < 0.05), while blood pressure, heart rate, Apgar scores and blood gas analysis of the umbilical artery and vein were not significantly different among the groups. No awareness was observed in the subjects. CONCLUSIONS: We found that the use of sevoflurane at on end-tidal concentration of 1.2 vol% was desirable to prevent recall by parturients, in the absence of fetal depression and a decline in uterine contractility.