瑞芬太尼用于术中麻醉

目的比较瑞芬太尼和芬太尼用于术中麻醉的安全性和有效性.方法54例择期行改良乳腺癌根治或全子宫切除术患者随机分为瑞芬太尼和芬太尼组,每组27例.麻醉诱导采用静脉注射丙泊酚(2 mg/kg)和瑞芬太尼(2 μg/kg)或芬太尼(2.5 μg/kg).麻醉维持采用吸入氧化亚氮和氧气(2:1),以及持续静脉泵注瑞芬太尼(0.2 μg·kg-1·min-1)或芬太尼(0.03 μg·kg-1·min-1).观察术中麻醉深度、血流动力学变化、麻醉苏醒、术后镇痛及不良反应等情况.结果在气管插管和麻醉维持期间,瑞芬太尼组麻醉深度不足的病例数明显少于芬太尼组(P＜0.05).在气管插管、切皮、麻醉维持和拔除气管导管期间,瑞芬太尼组患者血流动力学变化幅度显著小于芬太尼组(P＜0.05,P＜0.01).两组患者从手术结束到呼之睁眼和拔除气管导管的时间相似.瑞芬太尼组需静脉注射吗啡行术后镇痛的患者数明显多于芬太尼组(P＜0.05).在不良反应方面两组间无显著性差异.结论瑞芬太尼的麻醉和镇痛效果比芬太尼强,可使术中血流动力学更为稳定,同时不影响麻醉恢复.     

Pharmacokinetics of remifentanil and its major metabolite, remifentanil acid, in ICU patients with renal impairment

Background. The pharmacokinetics of remifentanil, an opioidanalgesic metabolized by non-specific esterases, and its principalmetabolite, remifentanil acid (RA), which is excreted via thekidneys, were assessed as part of an open-label safety studyin intensive care unit (ICU) patients with varying degrees ofrenal impairment. Methods. Forty adult ICU patients with normal/mildly impairedrenal function (creatinine clearance [CL_cr] 62.9 (SD) 14.5 mlmin^–1; n=10) or moderate/severe renal impairment (CL_cr14.7 (15.7) ml min^–1; n=30) were included. Remifentanilwas infused for up to 72 h, at a starting rate of 6–9µg kg^–1 h^–1 titrated to achieve a target sedationlevel, with additional propofol (0.5 mg kg^–1 h^–1)if required. Intensive arterial sampling was performed for upto 72 h after infusion. Pharmacokinetic parameters obtainedby simultaneous modelling of remifentanil and RA data were statisticallycompared between the two groups. Results. Remifentanil pharmacokinetics were not significantlyaffected by renal status. RA clearance in the moderate/severegroup was reduced to about 25% that of the normal/mild group(41 (29) vs 176 (49) ml kg^–1 h^–1, P<0.0001).Metabolic ratio, a predictor of the ratio of RA to remifentanilconcentrations at steady state, was approximately eight-foldhigher in the moderate/severe group relative to the normal/mildgroup (116 (110) vs 15 (4), P<0.0001). Maximum RA levelsapproached 700 ng ml^–1 in the moderate/severe group. Conclusions. Although RA accumulates in patients with moderate/severerenal impairment, pharmacokinetic modelling predicts that RAconcentrations during a 9 µg kg^–1 h^–1 remifentanilinfusion for up to 15 days would not exceed those reported inthe present study, for which no associated prolongation of µ-opioideffects was observed. Br J Anaesth 2004; 92: 493–503     

Anaesthesia for carotid endarterectomy: comparison of hypnotic- and opioid-based techniques

Background. Although the synergistic interaction between hypnoticsand opioids for total i.v. anaesthesia has been repeatedly demonstrated,questions about different dose combinations of hypnotics andopioids remain. The optimal combination would be based on maximalsynergy, using the lowest dose of both drugs and having thelowest incidence of side-effects. Methods. The major goal of this prospective randomized studywas to compare two different dose combinations of propofol andremifentanil (both administered by target controlled infusion(TCI)) in respect of haemodynamics during surgery and recovery,and the need for cardiovascular treatment in the recovery room.A secondary goal was to compare pain scores (VAS) and morphineconsumption in the recovery room. Anaesthesia was induced inboth groups using TCI propofol, adjusted to obtain a bispectralindex score (BIS) value between 40 and 60. TCI for remifentanilcommenced at an initial effect-site concentration of 0.5 ng ml^–1,and was adjusted according to haemodynamics. Patients were dividedinto one of two groups during anaesthesia: (i) Group H, hypnoticanaesthesia (n=23), propofol effect-site concentration maintainedat 2.4 µg ml^–1; and (ii) Group O, opioidanaesthesia (n=23), propofol effect-site concentration maintainedat 1.2 µg ml^–1. In both groups, remifentanileffect-site concentration was adjusted according to haemodynamicsand changes in BIS value. Results. In Group O, more episodes of intraoperative hypotension(P<0.02) and hypertension (P<0.01), and fewer episodesof tachycardia were observed. More patients in Group O requirednicardipine administration for postoperative hypertension (8patients in Group H vs 15 patients in Group O, P<0.04). Duringrecovery, morphine titration was necessary in     

The use of remifentanil for intubation in paediatric patients during sevoflurane anaesthesia guided by Bispectral Index (BIS) monitoring

We studied the intubating conditions, haemodynamic and endocrine changes following tracheal intubation during sevoflurane anaesthesia guided by Bispectral Index (BIS) monitoring in 40 children who received either remifentanil 1 microg.kg-1 (group R) or saline 1 ml.kg-1 (group S). Acceptable intubating conditions were found in all patients in group R (n = 20), compared to only 12 patients in group S (p = 0.002). There were no intergroup differences in heart rate, systolic blood pressure and plasma concentrations of epinephrine and norepinephrine at any time point and changes in haemodynamic variables throughout the study period were moderate. Titration of sevoflurane delivery to a target BIS of 35 +/- 5 led to almost equal end-tidal sevoflurane concentrations in either group and remifentanil did not affect the BIS. There were no side-effects in either group that required intervention. Intubating conditions during sevoflurane anaesthesia in children were found to be improved by a single bolus dose of remifentanil 1 microg.kg-1.     

Catecholamine release during laparoscopic fundoplication with high and low doses of remifentanil

Background:   Reports on stress responses to laparoscopic surgery have been conflicting. Depth of anesthesia may influence the neuro-hormonal release, including catecholamines. Opioids depress general sympathetic activation in a dose-dependent manner. We investigated the hypothesis that remifentanil would depress the catecholamine response to pneumoperitoneum and laparoscopic surgery differently with a high dose (HD) compared with a low dose (LD).
Methods:   In a randomized, prospective study we investigated 18 ASA I–II patients undergoing laparoscopic fundoplication with an intra-abdominal pressure of 12 mmHg. The patients were randomized to receive either a LD (0.13 μg kg⁻¹.min⁻¹) or HD (0.39 μg kg⁻¹.min⁻¹) of remifentanil with a target-controlled infusion (TCI) technique. Bispectral index of EEG (BIS) was maintained at 40–55 by propofol delivered by a TCI system. Arterial catecholamines were analyzed at different times during the procedure.
Results:   Norepinephrine increased equally in both groups during pneumoperitoneum and surgical intervention. Epinephrine stayed low in the HD-group, while increasing during surgery in the LD-group.
Conclusion:   High dose of remifentanil depressed the epinephrine response to pneumoperitoneum and surgery, indicating no general activation of the sympathetic nervous system. Neither a LD nor HD of remifentanil depressed the norepinephrine response during pneumoperitoneum. This suggests a centrally independent release of norepinephrine.     

Remifentanil-propofol vs. sufentanil-propofol: optimal combinations in clinical anesthesia

BACKGROUND: Two opioid regimens, computer-simulated to provide optimal general anesthesia in combination with propofol, were compared using clinical criteria. METHODS: Fifty patients undergoing thyroid surgery were blindly, prospectively and randomly allocated to receive either (a) i.v. remifentanil (1.5 micro g kg-1, followed by 0.2 micro g kg-1 min-1) or (b) i.v. sufentanil (0.2 micro g kg-1 followed by 0.2 micro g kg-1 h-1). Remifentanil infusion was stopped at the last skin suture. Sufentanil infusion was stopped 30 min before the end of surgery. Intravenous propofol was titrated to keep BIS at 50+/-5. Remifentanil and sufentanil groups were compared with regards to (a) propofol delivery, (b) hemodynamic and recovery variables, and (c) effect-site propofol levels during a steady-state period for effect-site remifentanil and sufentanil levels. P<0.05 was significant. RESULTS: Groups were similar in demographic data; types and durations of surgery; total propofol consumption; and response, extubation and emergence times. During the steady-state period for the opioid delivery, the remifentanil and sufentanil effect-site levels were 5.3 ng ml-1 and 0.18 ng ml-1, respectively (potency ratio=30). In both opioid groups, in accordance with previous computer-simulations, the effect-site propofol concentrations remained (a) within a narrow range unaffected by surgical stimuli, (b) significantly smaller in the remifentanil group than in the sufentanil group, but (c) smaller than expected from previous computer-simulations. More patients required ephedrine following induction of anesthesia in the remifentanil compared with the sufentanil group. CONCLUSIONS: The present clinical trial conducted in thyroid surgery is consistent with previous computer-simulated opioid-propofol combinations with respect to intraoperative and recovery variables. Effect-site propofol ranges were, however, lower than expected.     

Remifentanil infusion for cleft palate surgery in young infants

BACKGROUND: The residual depressant effect of opioid is a major concern in infants scheduled for cleft palate repair. Remifentanil is associated with a fast and predictable recovery, independent of age. METHODS: About 40 infants in the 2-12 month age range were prospectively enrolled in this open study, to receive either remifentanil (infusion starting at 0.25 microg x kg(-1) x min(-1)) or sufentanil as part of a balanced anaesthesia regimen. Isoflurane was maintained at an endtidal concentration of 1.2% in oxygen and nitrous oxide and the opioid dosing was titrated to autonomic responses. Postoperative pain relief was provided by morphine infusion. Morphine administration started intraoperatively in the remifentanil group. RESULTS: Consistent haemodynamic stability was achieved throughout surgery in both groups. Infants of the remifentanil group required, on average, lower concentrations of isoflurane than children of the sufentanil group (1.2 +/- 0.2% vs 1.7 +/- 0.3%, P < 0.001). The median time from last suture to tracheal extubation was 12.5 min (5-25 min) in the remifentanil group and 15.0 min (10-30 min) in the sufentanil group. There was no evidence of hyperalgesia or enhanced morphine consumption in the remifentanil group compared with the sufentanil group. Postoperative pain scores were even lower in the remifentanil group, compared with the sufentanil group, soon after arrival in the postanaesthesia care unit. CONCLUSIONS: Remifentanil-based anaesthesia appeared well suited for primary cleft palate repair in young infants.     

Predictive performance of computer-controlled infusion of remifentanil during propofol/remifentanil anaesthesia

Background. The predictive performance of the available pharmacokineticparameter sets for remifentanil, when used for target-controlledinfusion (TCI) during total i.v. anaesthesia, has not been determinedin a clinical setting. We studied the predictive performanceof five parameter sets of remifentanil when used for TCI ofremifentanil during propofol anaesthesia in surgical patients. Methods. Remifentanil concentration–time data that hadbeen collected during a previous pharmacodynamic interactionstudy in 30 female patients (ASA physical status I, aged 20–65 yr)who received a TCI of remifentanil and propofol during lowerabdominal surgery were used in this evaluation. The remifentanilconcentrations predicted by the five parameter sets were calculatedon the basis of the TCI device record of the infusion rate–timeprofile that had actually been administered to each individual.The individual and pooled bias [median performance error (MDPE)],inaccuracy [median absolute performance error (MDAPE)], divergenceand wobble of the remifentanil TCI device were determined fromthe pooled and intrasubject performance errors. Results. A total of 444 remifentanil blood samples were analysed.Blood propofol and remifentanil concentrations ranged from 0.5to 11 µg ml^–1 and 0.1 to 19.6 ng ml^–1respectively. Pooled MDPE and MDAPE of the remifentanil TCIdevice were –15 and 20% for the parameter set of Mintoand colleagues (Anesthesiology 1997; 86: 10–23), 1 and21%, –6 and 21%, and –6 and 19% for the three parametersets described by Egan and colleagues (Anesthesiology 1996;84: 821–33, Anesthesiology 1993; 79: 881–92, Anesthesiology1998; 89: 562–73), and –24 and 30% for the parameterset described by Drover and Lemmens (Anesthesiology 1998; 89:869–77). Conclusions. Remifentanil can be administered by TCI with acceptablebias and inaccuracy. The three pharmacokinetic parameter setsdescribed by Egan and colleagues resulted in the least biasand best accuracy. Br J Anaesth 2003; 90: 132–41     

Comparison of remifentanil and fentanyl in patients undergoing modified radical mastectomy or total hysterectomy

Objective To compare the efficacy and safety of remifentanil and fentanyl in patients undergoing a modified radical mastectomy or total hysterectomy.Methods Fifty-four patients were evenly randomised into remifentanil group and fentanyl group. Anesthesia was induced by propofol (1-2 mg/kg) and either remifentanil (2 μg/kg) or fentanyl (2.5 μg/kg), and was maintained with inhalation of nitrous oxide in oxygen (2∶1) and continuous infusion of either remifentanil (0.2 μg·kg-1·min-1) or fentanyl (0.03 μg·kg-1·min-1). Results The number of patients exhibiting light anesthesia responses in the remifentanil group during intubation and the maintenance of anesthesia was significantly less than that in the fentanyl group. Both systolic and diastolic blood pressures in the fentanyl group were significantly higher than those in the remifentanil group during intubation, skin incision, maintenance of anesthesia and extubation. The time to opening eyes on command and the time for extubation after surgery was comparable between the two groups. More patients in the remifentanil group (25 patients) required bolus injection of morphine for postoperative pain relief than those in the fentanyl group (5 patients, P&lt;0.05). There was no significant difference between the two groups in terms of side effects.Conclusions Under the condition of this study protocol, the anesthetic and analgesic effects of remifentanil are more potent than those of fentanyl. Remifentanil can offer superior intraoperative hemodynamic stability in comparison with fentanyl, and has no compromising recovery from anesthesia.     

Comparative efficacy and safety of remifentanil and fentanyl in 'fast track' coronary artery bypass graft surgery: a randomized, double-blind study

This multi-centre, parallel group, randomized, double-blindstudy compared the efficacy and safety of high-dose remifentaniladministered by continuous infusion with an intermittent bolusfentanyl regimen, when given in combination with propofol forgeneral anaesthesia in 321 patients undergoing elective coronaryartery bypass graft surgery. A significantly lower proportionof the patients who received remifentanil had responses to maximalsternal spread (the primary efficacy endpoint) compared withthose who received fentanyl (11% vs 52%; P<0.001). More patientswho received remifentanil responded to tracheal intubation comparedwith those who received fentanyl (24% vs 9%; P<0.001). However,fewer patients who received remifentanil responded to sternalskin incision (11% vs 36%; P<0.001) and sternotomy (14% vs60%; P <0.001). Median time to extubation was longer in thesubjects who received remifentanil than for those who receivedfentanyl (5.1 vs 4.2 h; P=0.006). There were no statisticallysignificant differences between the two groups in the timesfor transfer from intensive care unit or hospital dischargebut time to extubation was significantly longer in the remifentanilgroup. Overall, the incidence of adverse events was similarbut greater in the remifentanil group with respect to shivering(P<0.049) and hypertension (P<0.001). Significantly moredrug-related adverse events were reported in the remifentanilgroup (P=0.016) There were no drug-related adverse cardiac outcomesand no deaths from cardiac causes before hospital dischargein either treatment group. Br J Anaesth 2001; 87: 718–26