Sevoflurane versus propofol for anesthetic induction: a meta-analysis

We performed this meta-analysis to compare the characteristics of sevoflurane and propofol for the induction of routine anesthesia and for laryngeal mask airway (LMA) insertion. The variables assessed were 1) time to loss of consciousness, 2) incidence of apnea during induction, 3) induction complications, 4) time for successful LMA insertion, 5) success with LMA insertion on first attempt, 6) patient dissatisfaction, and 7) postoperative nausea and vomiting. MEDLINE, Embase, and the Cochrane library databases between January 1992 and October 1999 were reviewed for randomized, controlled trials comparing anesthetic induction between sevoflurane/nitrous oxide and propofol. Data from the 12 randomized, controlled studies were used for the meta-analysis. Sevoflurane induction was associated with a trend toward higher patient dissatisfaction and higher first-time success with LMA. Apnea was less common in the sevoflurane group. The incidence of postoperative nausea and vomiting was significantly more frequent in the sevoflurane group (P < 0.05). This effect was still present when all other variables, except the induction methods, were controlled. The other pooled variables did not show a significant difference between sevoflurane and propofol. Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting. IMPLICATIONS: Sevoflurane and propofol had similar efficacy for anesthetic induction. However, for routine outpatient surgery, propofol may still be the preferred induction anesthetic because of its favorable induction of anesthesia characteristics, high patient satisfaction, and less frequent incidence of postoperative nausea and vomiting.     

Wakefulness during cesarean section after anesthetic induction with ketamine, thiopental, or ketamine and thiopental combined

Thirty-six pregnant women (ASA class I or II) at term who underwent general anesthesia and cesarean section received either ketamine, 1 mg/kg (n = 12); thiopental, 4 mg/kg (n = 13); or a combination of ketamine, 0.5 mg/kg, and thiopental, 2 mg/kg (n = 11). A blood pressure cuff inflated to 250 mm Hg isolated one arm from the effects of succinylcholine so that awareness during anesthesia could be assessed by asking the patient to move her hand. Although only one patient receiving ketamine responded to commands during anesthesia, 46% of patients receiving either thiopental or the combination responded to commands intraoperatively. No patient hallucinated, the incidence of dreams was low (11%), and no postoperative dysphoria was noted. Three patients (8%) had postoperative recall of intraoperative awareness; one had received thiopental and two the combination. Maternal intraoperative cardiovascular responses among the groups were similar, as were umbilical blood gas values, newborn Apgar scores, and neonatal neurobehavioral test scores at 4 and 24 hr. Ketamine more effectively blocked maternal responsiveness to commands and strong stimuli during the first few minutes after anesthetic induction for cesarean section than did thiopental or a combination of thiopental and ketamine, each at a lower dose.     

Comparative study of propofol with thiopental and etomidate in anesthetic induction]

Anesthetic characteristics were studied in three homogeneous groups of twenty patients ASA I who underwent intravenous anesthetic induction with propofol 2 mg/kg; thiopental 5 mg/kg; or etomidate 0.3 mg/kg. The unconsciousness time was similar in the three groups, whereas awaking time and time of response and orientation were longer after thiopental and etomidate than after propofol. Intravenous injection of the three anesthetic agents was followed by a decrease in systolic and diastolic arterial pressure. Heart rate increased after thiopental and etomidate and had only slight fluctuations after propofol. After tracheal intubation there was a significant increase in systolic and diastolic arterial pressure and heart rate in thiopental and etomidate group. These changes were minimal after propofol. The highest number of complications occurred after etomidate.     

Effect of anesthetic induction agents on cardiovascular neuroregulation in dogs

The goal of this study was to examine the hypothesis that intravenous anesthetic induction agents alter neuroregulation of the cardiovascular system. Additional goals were to investigate this in an animal model devoid of other drug effects. Healthy mongrel dogs had arterial catheters inserted and pneumatic occluders positioned around the thoracic aorta and inferior vena cava. After 10 to 14 days of recovery, neurocirculatory control mechanisms were assessed in the absence of anesthesia by recording changes in the RR interval of the electrocardiogram in response to alterations in systolic arterial pressure. Systolic pressure was manipulated over a range of 65 to 200 mm Hg by random occlusion of either the inferior vena cava (hypotension) or aortic (hypertension) occluders. The animals were then given bolus doses of either thiopental (20 mg/kg), diazepam (2 mg/kg), ketamine (5 mg/kg), or etomidate (1.2 mg/kg) on separate days and in random order. The arterial pressure alterations were repeated 3, 10, and 20 minutes after the drugs were given. Regression curves were calculated expressing the slope relation between RR interval and systolic pressure at awake control and each time point after drug administration. The responses were compared with control by repeat measures analysis of variance. Thiopental significantly decreased this slope relation for 10 minutes. Diazepam decreased this slope at 3 minutes only. Ketamine, like thiopental, decreased this slope for 10 minutes. Following etomidate, the slopes were similar to control. We conclude that thiopental, diazepam, and ketamine impair neurocirculatory control capabilities. The effect of diazepam is only transient, whereas that of thiopental and ketamine is longer, and etomidate does not affect these reflexes.     

Intravenous ketamine attenuates arterial pressure changes during the induction of anaesthesia with propofol

BACKGROUND AND OBJECTIVE: To investigate whether the administration of ketamine before induction with propofol produces a smaller decrease in arterial pressure. METHODS: Twenty-two patients were assigned to one of two groups to receive either propofol with ketamine (n = 11) or propofol alone (n = 11, control). Anaesthesia was induced with 2 mg kg-1 propofol and 0.5 mg kg-1 ketamine or 2 mg kg-1 propofol alone. Ketamine was administered 1 min prior to induction with propofol. Immediately after induction with propofol, vecuronium (0.15 mg kg-1) was administered. Four minutes after administration of vecuronium, tracheal intubation was performed. Anaesthesia was maintained using sevoflurane (0.5%) in 66% nitrous oxide until 3 min after intubation. Systolic, diastolic and mean arterial pressure and heart rate were recorded on arrival, directly before induction with propofol, prior to tracheal intubation, immediately after intubation and at 3 min after intubation. RESULTS AND CONCLUSIONS: Administration of ketamine before induction with propofol preserved haemodynamic stability compared with induction with propofol alone.     

瑞芬太尼复合异丙酚麻醉诱导对气管插管条件及血流动力学的影响

目的对比不使用肌松剂的情况下,瑞芬太尼或芬太尼复合异丙酚麻醉诱导后对气管插管条件及血流动力学的影响。方法60名病人分为2组,诱导后2rain行气管插管术。分别记录诱导前、诱导后lmin及插管后2min的平均动脉压（MAP）和心率（Ha）。插管条件由操作者给予评分。结果两组插管成功率均为100％。瑞芬太尼组插管条件满意率80％,芬太尼73％。两组诱导后MAP和HR值较基础值均下降（P〈0．05）。插管后两组间的MAP值差异有统计学意义（P（0．05）。结论瑞芬太尼复合异丙酚麻醉诱导取得了同芬太尼复合异丙酚麻醉诱导一样良好的插管条件,在抑制插管引起的心血管反应方面瑞芬太尼组优于芬太尼组。     

Comparison of sevoflurane and ketamine for anesthetic induction in children with congenital heart disease

Background:  Sevoflurane is widely used in pediatric anesthesia for induction. Ketamine has been preferred in pediatric cardiovascular anesthesia. Aim of this study was to compare the hemodynamic effects and the speed of ketamine and sevoflurane for anesthesia induction in children with congenital heart disease.
Materials and methods:  Children with congenital heart disease undergoing corrective surgery were included in the study. After oral premedication with midazolam (0.5 mg·kg⁻¹), anesthesia induction was started with 5 mg·kg⁻¹ intramuscular ketamine (group K). In the second group, induction was achieved with sevoflurane (group S); the first concentration was 3% and increased after every three breaths. Intravenous access time and intubation times were enrolled for each child. Hemodynamic data and oxygen saturation were recorded every 2 min and any event during induction period was also noted.
Results:  Forty-seven children were included in the study; 23 in group K and 24 in group S. Heart rates and oxygen saturation values were similar between groups during the study. No difference was found between intravenous access time and intubation times. However, blood pressure levels were significantly lower in group S after recording baseline values till the intubation time (at 4, 6, and 8 min). Respiratory complications observed during the study were mild and were less frequent in group K than in group S (4 vs 13).
Conclusion:  Ketamine appears a good alternative for induction in patients with congenital heart disease. It permits preservation of hemodynamic stability with minimal side effects.     

Comparison of propofol versus ketamine for anesthesia in pediatric patients undergoing cardiac catheterization.

Intravenous propofol was compared with ketamine in 20 pediatric patients undergoing cardiac catheterization. The study patients were randomly assigned to treatment groups so that 10 patients received ketamine and 10 patients received propofol. The hemodynamic responses and recovery characteristics of the two groups were compared. On induction of anesthesia, seven patients in the propofol group experienced a transient decrease in mean arterial blood pressure greater than 20% of baseline accompanied by mild arterial desaturation in four patients. Only one patient in the ketamine group experienced such a decrease in arterial blood pressure. This was the only significant difference (P less than 0.05) in hemodynamic effects between the two groups. Time to full recovery (mean +/- SD) was significantly less in the propofol group (24 +/- 19 min vs 139 +/- 87 min, P less than 0.001). In the ketamine group only, significant correlations (P less than 0.05) included time to full recovery with duration of anesthetic (r = 0.71) and time to full recovery with total drug dose per kilogram (r = 0.82). The authors conclude that propofol anesthesia is a practical alternative for pediatric patients undergoing elective cardiac catheterization and may be preferable to ketamine because of the significantly shorter recovery time.     

Effects of low dose ketamine before induction on propofol anesthesia for pediatric magnetic resonance imaging

BACKGROUND: We aimed to investigate effects of low dose ketamine before induction on propofol anesthesia for children undergoing magnetic resonance imaging (MRI). METHODS: Forty-three children aged 9 days to 7 years, undergoing elective MRI were randomly assigned to receive intravenously either a 2.5 mg x kg(-1) bolus of propofol followed by an infusion of 100 microg x g(-1) x min(-1) or a 1.5 mg x kg(-1) bolus of propofol immediately after a 0.5 mg x kg(-1) bolus of ketamine followed by an infusion of 75 microg x kg(-1) x min(-1). If a child moved during the imaging sequence, a 0.5-1 mg x kg(-1) bolus of propofol was given. Systolic and diastolic blood pressures, heart rate, peripheral oxygen saturation and respiratory rates were monitored. Apnea, the requirement for airway opening maneuvers, secretions, nausea, vomiting and movement during the imaging sequence were noted. Recovery times were also recorded. RESULTS: Systolic blood pressure and heart rate decreased significantly in the propofol group, while blood pressure did not change and heart rate decreased less in the propofol-ketamine group. Apnea associated with desaturation was observed in three patients of the propofol group. The two groups were similar with respect to requirements for airway opening maneuvers, secretions, nausea-vomiting, movement during the imaging sequence and recovery time. CONCLUSIONS: Intravenous administration of low dose ketamine before induction and maintenance with propofol preserves hemodynamic stability without changing the duration and the quality of recovery compared with propofol alone.