The effect-site concentration of remifentanil blunting cardiovascular responses to tracheal intubation and skin incision during bispectral index-guided propofol anesthesia

We sought to determine the effect-site concentration of remifentanil blunting sympathetic responses to tracheal intubation and skin incision during bispectral index (BIS)-guided propofol anesthesia. Forty-one ASA physical status I-II patients, aged 20-65 yr and undergoing major abdominal surgery, were randomly assigned to one of two groups: tracheal intubation (group TI, n = 20) or skin incision (group SI, n = 21). All patients received a target-controlled infusion of propofol of 4 microg/mL, which was then adjusted to maintain a BIS value ranging between 40 and 50. The effect-site concentration of remifentanil blocking the sympathetic responses to tracheal intubation and skin incision in 50% of cases (Ce50) was determined using an up-and-down sequential allocation method. The mean (95% confidence interval [CI]) Ce50 of remifentanil was 5.0 ng/mL for TI (95% CI, 4.7-5.4 ng/mL) and 2.1 ng/mL for SI (95% CI, 1.4-2.8 ng/mL). This study shows that effect-site concentrations of remifentanil of 5 ng/mL and 2 ng/mL are effective in blunting sympathetic responses to tracheal intubation and skin incision in 50% of patients when combined with a BIS-guided target controlled infusion of propofol.     

Remifentanil and fentanyl during anaesthesia for major abdominal and gynaecological surgery. An open, comparative study of safety and efficacy.

BACKGROUND: and objective This open, multicentre study compared the efficacy and safety of remifentanil with fentanyl during balanced anaesthesia with 0.8% isoflurane (end-tidal concentration) for major abdominal and gynaecological surgery, and the efficacy and safety of remifentanil for pain management in the immediate postoperative period. METHODS: Two-hundred and eighty-six patients were randomized to receive remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min-1 (n=98), remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) (n=91) or fentanyl 3 microg kg(-1) (n=97) at induction. Thereafter, the study opioids and isoflurane were titrated to effect during the operation. RESULTS: Compared with fentanyl, remifentanil 2 microg kg(-1) followed by 0.4 microg kg(-1) min(-1) reduced the incidence of response to tracheal intubation (30% vs. 13%, P < 0.01), skin incision (33% vs. 4%, P < 0.001) and skin closure (11% vs. 3%, P < 0.05), respectively. Patients receiving remifentanil 1 microg kg(-1) followed by 0.2 microg kg(-1) min(-1) had fewer responses to skin incision than the fentanyl group (12% vs. 33%, P < 0.001), but the incidences of response to tracheal intubation and skin closure were similar. Significantly fewer patients in both remifentanil groups had > or = 1 responses to surgical stress intraoperatively compared with fentanyl (68% and 48% vs. 87%, P < 0.003). The mean isoflurane concentrations required were less in both remifentanil groups compared with the fentanyl group (0.1%, P=0.05). In remifentanil-treated patients, continuation of the infusion at 0.1 microg kg(-1) min(-1) with titration increments of +/- 0.025 microg kg(-1) min(-1) was effective for the management of immediate postoperative pain prior to transfer to morphine analgesia. However, a high proportion of patients experienced at least moderate pain whilst the titration took place. CONCLUSIONS: Anaesthesia combining isoflurane with a continuous infusion of remifentanil was significantly more effective than fentanyl at blunting responses to surgical stimuli. Significantly fewer patients responded to tracheal intubation with remifentanil at 0.4 microg kg(-1) min(-1), supporting the use of a higher initial infusion rate before intubation. Both remifentanil and fentanyl were well-tolerated, with reported adverse events typical of mu-opioid agonists.     

Plasma concentrations of alfentanil required to supplement nitrous oxide anesthesia for general surgery

To design an efficient infusion regimen from pharmacokinetic data, it is necessary to know the alfentanil plasma concentrations required for satisfactory anesthesia. In 37 patients about to undergo lower abdominal gynecologic, upper abdominal, or breast surgery, anesthesia was induced with alfentanil 150 micrograms/kg iv and 66% N2O in oxygen. Thereafter, N2O anesthesia was supplemented with a continuous infusion of alfentanil that was varied between 25 and 150 micrograms X kg-1 X h-1, as indicated by the patient's responses to surgical stimulation. Small bolus doses of alfentanil 7 or 14 micrograms/kg were administered and the infusion rate increased to suppress precisely defined somatic, autonomic, and hemodynamic responses. Arterial plasma concentrations of alfentanil were measured during the operation when the patient did and did not respond to noxious stimulation. Logistic regression was used to determine plasma concentration-effect curves for different stimuli. Plasma alfentanil concentrations required along with 66% N2O to obtain responses to single episodes of stimulation in 50% of the 37 patients (Cp50 +/- SE) were: 475 +/- 28 ng/ml for tracheal intubation, 279 +/- 20 ng/ml for skin incision, and 150 +/- 23 ng/ml for skin closure. Between skin incision and closure, multiple determinations of response/no response were made for each patient and an individual Cp50 was estimated. The Cp50 (mean +/- SD) for the three surgical procedures were: breast, 270 +/- 63 ng/ml (n = 12); lower abdominal, 309 +/- 44 ng/ml (n = 14); and upper abdominal, 412 +/- 135 ng/ml (n = 11). The Cp50 for satisfactory spontaneous ventilation after the discontinuation of N2O was 223 +/- 13 ng/ml. These data demonstrate that different perioperative stimuli require different alfentanil concentrations to suppress undesirable responses. Thus, the alfentanil infusion rate should be varied according to the patient's responsiveness to stimulation in order to maintain satisfactory anesthetic and operative conditions and to provide rapid recovery of consciousness and spontaneous ventilation.     

Tracheal intubation without muscle relaxants: remifentanil or alfentanil in combination with propofol

BACKGROUND AND OBJECTIVE: In some situations, the use of muscle relaxants (neuromuscular blocking drugs) are undesirable or contraindicated. We compared intubating conditions without muscle relaxants in premedicated patients receiving either alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) followed by propofol 2 mg kg(-1). METHODS: In a randomized, double-blind study, 80 healthy patients were assigned to one of four groups (n = 20). After intravenous atropine, alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) were injected over 90 s followed by propofol 2 mg kg(-1). Ninety seconds after administration of the propofol, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of lung ventilation, jaw relaxation, laryngoscopy, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff. RESULTS: Seven patients who received remifentanil 2 microg kg(-1) and one patient who received remifentanil 3 microg kg(-1) could not be intubated at the first attempts. Excellent intubating conditions (jaw relaxed, vocal cords open and no movement in response to tracheal intubation and cuff inflation) were observed in those who received either alfentanil 40 microg kg(-1) (45% of patients) or remifentanil in doses of 2 microg kg(-1) (20%), 3 microg kg(-1) (75%) or 4 microg kg(-1) (95%). Overall, intubating conditions were significantly better (P < 0.05), and the number of patients showing excellent conditions were significantly higher (P < 0.05) in patients who received remifentanil 4 microg kg(-1) compared with those who received alfentanil 40 microg kg(-1) or remifentanil 2 microg kg(-1). No patient needed treatment for hypotension or bradycardia. CONCLUSIONS: Remifentanil 4 microg kg(-1) and propofol 2 mg kg(-1) administered in sequence intravenously provided good or excellent conditions for tracheal intubation in all patients without the use of muscle relaxants.     

Comparison of propofol-alfentanil and propofol-remifentanil anaesthesia in percutaneous nephrolithotripsy

BACKGROUND AND OBJECTIVE: Percutaneous nephrolithotripsy (PCNL) is used for the fragmentation and removal of stones from the renal pelvis and renal calyceal systems. We compared the effects of propofol-alfentanil or propofol-remifentanil anaesthesia on haemodynamics, recovery characteristics and postoperative analgesic requirements during percutaneous nephrolithotripsy. METHODS: Thirty non-premedicated patients were randomly allocated to receive either propofol-alfentanil (Group A) or propofol-remifentanil (Group R). The loading dose of the study drug was administered over 60 s (alfentanil 10 microg kg(-1) or remifentanil 1 microg kg(-1)) followed by a continuous infusion (alfentanil 15 microg kg(-1) h(-1) or remifentanil 0.15 microg kg(-1) min(-1)). Propofol was administered until loss of consciousness and maintained with a continuous infusion of 75 microg kg(-1) min(-1) in both groups. Atracurium was given for endotracheal intubation at a dose of 0.5 mg kg(-1) and maintained with a continuous infusion of 0.4 mg kg(-1) h(-1). Mean arterial pressure heart rate, the total amount of propofol, time of recovery of spontaneous ventilation, extubation and eye opening in response to verbal stimulus and analgesic requirement were recorded. RESULTS: In Group A, mean arterial pressure was higher at the first minute in the prone position, and during skin incision and lithotripsy, and heart rate was higher during skin incision and lithotripsy when compared with Group R (P < 0.05). The total amount of propofol did not differ between groups. Time of recovery of spontaneous ventilation, extubation and eye opening were significantly shorter in Group R than Group A (P < 0.05). CONCLUSIONS: Both propofol-remifentanil and propofol-alfentanil anaesthesia provided stable haemodynamics during percutaneous nephrolithotripsy, whereas propofol-remifentanil allowed earlier extubation.     

Remifentanil versus alfentanil in total intravenous anaesthesia for day case surgery

BACKGROUND AND OBJECTIVE: We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery. METHODS: Patients in Group 1 (n = 20) received alfentanil 20 microg kg(-1) followed by 2 microg kg(-1) min(-1) intravenously; patients in Group 2 (n = 20) received remifentanil 1 microg kg(-1) followed by 0.5 microg kg(-1) min(-1) intravenously. Both groups then received propofol 2 mg kg(-1) followed by 9 mg kg(-1) h(-1) intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS). RESULTS: Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score > or = 9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores > or = 9 were similar. CONCLUSIONS: Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.     

Small doses of remifentanil and alfetanil in continuous total intravenous anesthesia in major abdominal surgery. A double blind comparison

AIM: The purpose of this study was to test the safety and efficacy of small doses of remifentanil and alfentanil in a continuous total intravenous anesthesia technique for patients undergoing major abdominal surgery. METHODS: Sixty patients were enrolled in the study, and received in a double blind fashion either remifentanil (0.1 microg/kg/min) or alfentanil (alfentanil 0.75 microg/kg/min) in association with propofol (12 mg/kg/h at induction; 6-9 mg/kg/h for maintenance) and cisatracurium. Hemodynamic data, hypnosis monitoring data (Bispectral Index Score), ventilatory parameters and settings, drug utilisation were monitored during stress moments and during all the intraoperative period. Patients were evaluated also in the first 6 postoperative hours. RESULTS: Mean amount of propofol for induction (BIS<60) was lower in the remifentanil group than in the alfentanil group. Significantly fewer patients receiving remifentanil responded to intubation in comparison with patients receiving alfentanil in terms of non invasive blood pressure (>30 mmHg) and heart rate variations. Significantly more patients receiving alfentanil had 1 or more responses to surgery. Incidence of hypotension was significantly higher in patients receiving remifentanil. There were no differences between the 2 groups in the times for spontaneous respiration, adequate respiration, adequate responsivness (OAA/s=5) and discharge from the recovery room. Time to extubation resulted slightly shorter (p<0.05) in patients who received remifentanil. CONCLUSIONS: The use of remifentanil and alfentanil in association with propofol, in a continuous infusion total intravenous anesthesia technique, demonstrated to be safe and reliable strategies.     

Comparison of hemodynamics,recovery profile,and early postoperative pain control and costs of remifentanil versus alfentanil-based total intravenous anesthesia (TIVA)

STUDY OBJECTIVE: To compare hemodynamics, recovery profiles, early postoperative pain control and costs of total intravenous anesthesia (TIVA) with propofol and remifentanil and propofol and alfentanil. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 40 ASA physical status I and II adult patients scheduled for lumbar discectomy. INTERVENTIONS: Patients were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 1 microg kg(-1) or alfentanil 20 microg kg(-1) with propofol 2 mg kg(-1), and maintained with infusions of propofol 150 to 100 microg kg(-1)min(-1) and either remifentanil 0.1 microg kg(-1) min(-1) or alfentanil 0.5 microg kg(-1) min(-1). MEASUREMENTS: Hemodynamic parameters (heart rate and mean arterial pressure), times to awakening, and tracheal extubation were recorded. In the postanesthesia care unit, pain level, frequency of analgesic demand, frequency of postoperative nausea and vomiting (PONV), partial oxygen saturation (SpO2), and respiratory rates were noted. Drug dosages and costs of each technique were determined. MAIN RESULTS: The mean arterial pressure significantly decreased compared to baseline values 1 minute after induction (p < 0.05) in both groups, and it significantly decreased at 5, 15, and 30 minutes perioperatively in the remifentanil group compared to the alfentanil group (p < 0.05). Time of extubation, spontaneous eye opening, and response to verbal command were similar in both groups. Visual analog scale pain scores at 30 minutes and 60 minutes were significantly lower in the alfentanil group than remifentanil group (p < 0.05). At 15, 30, and 60 minutes after terminating the operation oxygen saturation and respiratory rate were significantly higher (p < 0.05) and analgesics were required sooner in the remifentanil group than the alfentanil group (p < 0.05). The frequency of PONV was similar in both groups. The remifentanil-propofol anesthesia was found to be slightly more expensive as compared to the alfentanil based TIVA (33.41 +/- 4.53 vs. 29.97 +/- 4.1 USD) (p < 0.05). CONCLUSIONS: Both remifentanil and alfentanil provided a reasonably rapid and reliable recovery. The remifentanil-based TIVA was associated with high intraoperative cost and early postoperative pain, but it allowed a more rapid respiratory recovery.     

Sevoflurane with remifentanil allows rapid tracheal intubation without neuromuscular blocking agents

PURPOSE: After inhalational induction with sevoflurane, we compared the effects of adding remifentanil 1 microg x kg(-1) or remifentanil 2 microg x kg(-1) on conditions for tracheal intubation without neuromuscular blocking agents. METHODS: Before anesthetic induction, all patients were given 0.2 mg of glycopyrrolate iv to counteract the bradycardic effects of remifentanil. Two minutes after inhalational induction with 8% sevoflurane and 50% nitrous oxide, 56 female patients with normal airways scheduled for gynecologic surgery were randomized to receive remifentanil 1 or 2 microg x kg(-1) in a double-blind fashion. One minute later, laryngoscopy was initiated for tracheal intubation. Conditions for tracheal intubation and hemodynamic response to tracheal intubation were assessed. RESULTS: Tracheal intubation was successful in all patients. The incidence of post-intubation coughing was lower in the remifentanil 2 microg x kg(-1) group compared to remifentanil 1 microg x kg(-1) group (11% vs 39%, P <0.02). Optimal intubation conditions were also higher in the remifentanil 2 microg x kg(-1) group at 89% vs 54% (P <0.01). However, the higher dose of remifentanil also resulted in a greater decrease in mean arterial pressure (P <0.05). CONCLUSIONS: The addition of remifentanil after sevoflurane induction allows for rapid tracheal intubation without neuromuscular blocking agents. The higher dose of remifentanil results in improved conditions for tracheal intubation but also caused a greater decrease in mean arterial pressure. Tracheal intubation using sevoflurane and remifentanil may be an alternative to traditional tracheal intubation with neuromuscular blocking agents.     

Fentanyl is more effective than remifentanil at preventing increases in cerebral blood flow velocity during intubation in children

PURPOSE: Controlling the cerebral and systemic hemodynamic responses to laryngoscopy and tracheal intubation may play a role in determining clinical outcome in pediatric neurosurgical patients. This study compared the effects of remifentanil and fentanyl on cerebral blood flow velocity (CBFV) and hemodynamic profile during laryngoscopy and tracheal intubation in children under sevoflurane anesthesia. METHODS: Sixty healthy children aged two to six years undergoing dental surgery under general anesthesia were enrolled. Each child was randomly assigned to receive a remifentanil or fentanyl infusion, at a rate of 0.75, 1.0, or 1.5 microg x kg(-1) x min(-1) after induction of anesthesia with 2% sevoflurane. Middle cerebral artery blood flow velocity was measured by transcranial Doppler (TCD) sonography. Once a baseline set of hemodynamic variables and TCD measurements were recorded, the opioid infusion was started. Measurements were taken at two-minute intervals, starting four minutes prior to laryngoscopy until four minutes following naso-tracheal intubation. RESULTS: Remifentanil caused a more significant decrease in mean arterial pressure and CBFV prior to tracheal intubation than did fentanyl (P < 0.001). During laryngoscopy and for two minutes following tracheal intubation, CBFV increased in all remifentanil groups (P < 0.05), whereas it remained stable in all fentanyl groups. CONCLUSION: This study suggests that fentanyl was more effective than remifentanil at preventing increases in CBFV during and immediately following laryngoscopy and tracheal intubation in children undergoing sevoflurane anesthesia. Fentanyl also seemed to provide a more stable hemodynamic profile prior to laryngoscopy and tracheal intubation when compared to remifentanil.     

Prevention of rocuronium-induced withdrawal movement in children: a comparison of remifentanil with alfentanil

BACKGROUND: This study was designed to compare the efficacy of remifentanil and alfentanil without the venous occlusion technique in preventing the withdrawal response associated with rocuronium injection in children. METHODS: One hundred and twenty children aged between 3 and 10 years were randomly allocated into one of four groups to receive either i.v. remifentanil 0.5 microg.kg(-1) (remi 0.5 group), remifentanil 1 microg.kg(-1) (remi 1.0 group), alfentanil 15 microg.kg(-1) (alfentanil group) or saline 5 ml (saline group). Anesthesia was induced with 2.5% thiopental sodium 5 mg.kg(-1) and the test drug was injected over 30 s. One minute later, 1% rocuronium 0.6 mg.kg(-1) was injected over 5 s and the response was recorded. Mean arterial pressure (MAP) and heart rate (HR) were recorded on arrival in the operating room, before and 1 min after tracheal intubation. RESULTS: The incidence of withdrawal movement in the saline group (93%) was significantly higher than that in the remi 0.5, remi 1.0, and alfentanil groups (53%, 17%, and 20%, respectively) (P < 0.05). The incidence in the remi 1.0 and alfentanil groups was significantly less than that in the remi 0.5 group (P < 0.05). After intubation, MAP and HR were significantly higher in the saline group than that in remi 1.0 and alfentanil groups. CONCLUSIONS: Both remifentanil 1 microg.kg(-1) and alfentanil 15 microg.kg(-1) can be used to prevent rocuronium-associated withdrawal movement in children because they are equally effective and attenuate the increase in MAP and HR after intubation.     

Fast-track cardiac anesthesia: efficacy and safety of remifentanil versus sufentanil

OBJECTIVE: The purpose of this study was to compare the safety and efficacy of fast-track cardiac anesthesia with remifentanil (group R) versus sufentanil (group S). DESIGN: Prospective, single-blinded, randomized study. SETTING: University hospital. PARTICIPANTS: One hundred twenty patients undergoing coronary artery bypass graft surgery and/or cardiac valve surgery. INTERVENTIONS: After routine standardized anesthesia induction, anesthesia was maintained with isoflurane (0.4-0.8 vol%) together with either remifentanil (group R) (1 microg/kg/min) or sufentanil (group S) (1 microg/kg for induction, 0.5 microg/kg for skin incision, and then 0.02 microg/kg/min). After surgery, which included cardiopulmonary bypass in all cases, postoperative sedation was achieved in both groups with propofol until the patient was deemed ready for extubation. Additionally, patients in group R received remifentanil, 0.25 microg/kg/min. MEASUREMENTS AND MAIN RESULTS: Recovery profile in group R patients was faster (p < 0.05), with a median time interval between end of surgery and eligibility for extubation of 295 minutes versus 375 minutes. Time from end of surgery to being eligible for discharge from intensive care unit was similar in both groups, with 22.9 hours in group R versus 26.3 hour in group S. Remifentanil provided a better protection against intraoperative stimuli at skin incision and maximal sternal spread (p < 0.05). The incidence of adverse events was comparable in both groups. Postoperative pain scores during the first hour of weaning were higher in group R (p < 0.05). CONCLUSIONS: Remifentanil for fast-track cardiac anesthesia provided safe and stable operating conditions and facilitated earlier tracheal extubation. However, postoperative pain management should be planned carefully.     

异丙酚麻醉下瑞芬太尼抑制不同年龄老年患者气管插管和切皮反应的半数有效血浆靶浓度

目的 确定异丙酚麻醉下瑞芬太尼抑制不同年龄老年患者气管插管和切皮反应的半数有效血浆靶浓度(EC50).方法 择期全麻老年患者116例,年龄60～79岁,体重39～82 kg,ASA Ⅰ～Ⅲ级,按年龄及刺激不同分为4组,靶控输注异丙酚,待患者意识消失时靶控输注瑞芬太尼,Ⅰ-TI组(60～69岁,n=33)和Ⅱ-TI组(70～79岁,n=31)第1例患者瑞芬太尼初始血浆靶浓度设为3.5 ng/ml,待效应室浓度与血浆靶浓度达平衡后静脉注射维库溴铵0.1 me,/kg,3 min后行气管插管.Ⅰ-SI组(60～69岁,n=26)和Ⅱ-SI组(70～79岁,n=26)第1例患者气管插管后瑞芬太尼初始血浆靶浓度设为2.5 ng/ml,待效应室浓度与血浆靶浓度达平衡后维持10 min,开始切皮,采用改良序贯法进行试验.发生心血管反应的标准:气管插管或切皮后3 min内平均动脉压或心率较气管插管或切皮前的基础值升高超过20%.计算各组EC50及其95%可信区间(CI).结果 Ⅰ-TI组和Ⅱ-TI组瑞芬太尼抑制气管插管反应的EC50及其95%CI分别为2.90(2.76～3.04)ng/ml和3.16(2.90～3.41)ng/ml,差异无统计学意义(P>0.05);Ⅰ-SI组和Ⅱ-SI组瑞芬太尼抑制切皮反应的EC50及95%CI分别为1.90(1.76～2.04)ng/ml和1.77(1.68～1.85)ng/ml,差异无统计学意义(P>0.05);与Ⅰ-TI组比较,Ⅰ-SI组EC50降低(P<0.05);与Ⅱ-TI组比较,Ⅱ-SI组EC50降低(P<0.05).结论 60～69岁患者靶控输注异丙酚至意识消失时瑞芬太尼抑制气管插管和切皮反应的EC50分别为2.90、1.90ng/ml,70～79岁患者分别为3.16、1.77 ng/ml,不随年龄增加而改变.     

Time of peritoneal cavity exposure influences postoperative glucose production

PURPOSE: To examine the effect of the duration of peritoneal cavity exposure on glucose metabolism after abdominal surgery. METHODS: In eight otherwise healthy patients (ASA 1) with uterine myoma, endogenous glucose production (Ra glucose) was measured immediately before and two hours after abdominal hysterectomy by a stable isotope dilution technique using primed continuous infusions of [6,6-2H2]-glucose. Plasma concentrations of glucose, lactate, insulin, glucagon, cortisol, epinephrine and norepinephrine were determined before, during (5 and 60 min after peritoneal incision, skin closure) and two hours after surgery. Pre- and postoperative glucose clearance was calculated as Ra glucose divided by plasma glucose concentration. RESULTS: Ra glucose increased from 11.8 +/- 1.2 to 16.8 +/- 3.2 micromol x kg(-1) x min(-1) two hours after hysterectomy (P < 0.05) with a correlation between the degree of increase and the time of peritoneal cavity exposure (r = 0.859, P = 0.006). Plasma glucose concentration increased after surgery from 4.7 +/- 0.8 to 8.3 +/- 1.9 mmol x l(-1) (P < 0.05), while glucose clearance decreased from 2.6 +/- 0.4 to 2.1 +/- 0.4 ml x kg(-1) x min(-1) (P < 0.05). Plasma concentrations of cortisol and catecholamines increased after hysterectomy (cortisol from 6 +/- 2 to 31 +/- 7 microg x dl(-1), epinephrine from 25 +/- 14 to 205 +/- 132 pg x ml(-1), norepinephrine from 182 +/- 82 to 377 +/- 132 pg x ml(-1), P < 0.05), whereas plasma lactate, insulin and glucagon concentrations remained unchanged. CONCLUSION: The magnitude of increase of glucose production after abdominal hysterectomy is associated with the duration of peritoneal cavity exposure.     

Low alfentanil target-concentrations improve hemodynamic and intubating conditions during induction with sevoflurane

PURPOSE: To investigate the effects of different alfentanil target-concentrations on hemodynamics, respiration and conditions of tracheal intubation during an inhalation induction with 8% sevoflurane. METHODS: In this prospective randomized open-label study, 40 ASA I adult patients received alfentanil at the following target-concentrations: zero (Group 0), 25 (Group 25), 50 (Group 50) and 75 ng*mL(-1) (Group 75), starting five minutes before induction of anesthesia with 8% sevoflurane in 50% nitrous oxide. The ease of intubation was determined on fixed criteria and scored; arterial pressure, heart rate and bispectral index (BIS) were recorded at one-minute intervals. RESULTS: Times to allow tracheal intubation were shortened only in Group 75 (94 +/- 8 sec) as compared to Group 0 (140 +/- 11 sec, P < 0.05). BIS values, tracheal intubation scores and number of attempts were not different between groups. However, more patients suffered from apnea in Group 75. Heart rate and mean arterial pressure remained stable in Group 75 whereas they increased significantly in the three other groups. No patient suffered hypotension. CONCLUSION: Adding alfentanil at a 75 ng*mL(-1) target-concentration during an inhalation induction with 8% sevoflurane in 50% nitrous oxide allows intubation slightly earlier and provides stable hemodynamic conditions but the incidence of apnea during induction is higher. Lower concentrations are of little clinical interest.     

Der Einfluß einer totalen intravenösen Anästhesie mit S-(+)-Ketamin/Propofol auf hämodynamische,endokrine und metabolische Streßreaktionen im Vergleich zu Alfentanil/Propofol bei Laparotomien

Total intravenous anaesthesia with ketamine-propofol offers distinct advantages over a TIVA with an opiate, including less cardiovascular and respiratory depression and an altered neuroendocrine and immunological stress response pattern. The effects of the more active stereoisomer S-(+)-ketamine in combination with propofol on the circulatory, endocrine and metabolic responses to abdominal surgery were compared with those of alfentanil-propofol. Twenty-four patients scheduled for elective hysterectomy participated in this study, which had the approval of our institution's ethics committee. Anaesthesia was induced with 2?mg/kg S-(+)-ketamine or 0.05?mg/kg alfentanil, followed by 1?mg/kg propofol. Tracheal intubation was facilitated with 0.06?mg/kg vecuronium. Anaesthesia was maintained with 1?mg/kg per h S-(+)-ketamine or 0.125?mg/kg per h alfentanil and propofol at an initial rate of 15?mg/kg per h which was reduced to 5?mg/kg per h after 30?min. Blood samples for catecholamines, cortisol and metabolites were drawn at predetermined times from before induction to 6?h postoperatively. Adrenaline and noradrenaline concentrations decreased preoperatively in the ketamine group (K) from 55 to 29?pg/ml and 166 to 39?pg/ml, respectively, and then increased to postoperative maxima of 193 or 315?pg/ml. A similar pre- and postoperative course was seen in the alfentanil group (A) with slightly lower (P<0.05) intraoperative concentrations in A. Cortisol concentrations increased in K from 12?μg/dl to 34?μg/dl intraoperatively and further to a maximum of 42?μg/dl postoperatively. The intraoperative increase was attenuated in A and the difference between the groups was significant (P<0.0001). The initial ketamine bolus and tracheal intubation caused a marked, transient increase of mean arterial blood pressure from the baseline value of 105?mmHg to 120 mmHg with a subsequent decrease to 88?mmHg prior to skin incision and a gradual return to baseline during surgery. TIVA with ketamine-propofol had little effect on the perioperative courses of the endocrine parameters, which behaved as they do under anesthesia with isoflurane-nitrous oxide. Plasma catecholamine concentrations were not elevated in the period between induction of anaesthesia and skin incision.     

Propofol is superior to thiopental for intubation without muscle relaxants

PURPOSE: To compare intubating conditions and cardiovascular changes following induction of anesthesia and tracheal intubation in patients receiving either lidocaine-remifentanil-propofol or lidocaine-remifentanil-thiopental prior to induction. METHODS: In a randomized, double-blind study 76 healthy adult patients were assigned to one of two groups: lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and propofol 2 mg.kg(-1) (Group P) or lidocaine 1.5 mg.kg(-1), remifentanil 2 mug.kg(-1) and thiopental 5 mg.kg(-1) (Group T). Ninety seconds after the administration of the hypnotic agent, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient's response to intubation and slow inflation of the tracheal cuff. The mean arterial pressure (MAP) and heart rate (HR) were measured 45 sec after hypnotic agent administration, immediately after tracheal intubation, two and five minutes after intubation. RESULTS: Excellent intubating conditions were obtained in 84% of Group P patients and 50% of Group T patients (P < 0.05). The percentage decrease from baseline MAP was significantly higher in Group P than in Group T postinduction (27.4% +/- 11.6 vs 21.8% +/- 10.0) and immediately postintubation (19.0% +/- 16.7 vs 11.2% +/- 14.9). The percentage change from baseline HR was significantly higher in Group P than in Group T postinduction (13.8% +/- 9.7 vs 0.5% +/- 12.4), immediately postintubation (8.7% +/- 13.7 vs 2.1% +/- 13.1), and two minutes postintubation (7.04% +/- 14.3 vs 3.5% +/- 14.3). CONCLUSION: Lidocaine-remifentanil-propofol is superior to lidocaine-remifentanil-thiopental for tracheal intubation without muscle relaxants. However, it induces more hypotension and bradycardia.     

Effects of alfentanil and lidocaine on the hemodynamic responses to laryngoscopy and tracheal intubation

This study was undertaken to determine whether lidocaine and/or alfentanil can effectively abolish or attenuate the increase in mean arterial pressure (MAP), heart rate (HR), and rate pressure product (RPP) associated with rapid sequence induction of anesthesia. Sixty patients were randomly divided into four groups. Group 1 received saline 10 ml, group 2 received lidocaine 2 mg/kg, group 3 received alfentanil 15 micrograms/kg, and group 4 received alfentanil 30 micrograms/kg. All patients were induced with sodium thiopental 4 mg/kg and succinylcholine 1.5 mg/kg to facilitate tracheal intubation. The study drug was given after sodium thiopental was administered, and the investigator was blinded to it. Blood pressure (BP) and HR were recorded at the following times: before induction; after induction but before laryngoscopy and intubation; and 1, 3, and 5 minutes after intubation. Alfentanil 15 and 30 micrograms/kg given in rapid sequence fashion with thiopental and succinylcholine effectively blunted the hemodynamic responses to laryngoscopy and tracheal intubation. Lidocaine 2 mg/kg and saline were found to be ineffective in blunting these same responses.     

Assessment of tracheal intubating conditions in children using remifentanil and propofol without muscle relaxant

BACKGROUND: Tracheal intubation in children can be achieved by deep inhalational anaesthesia or an intravenous anaesthetic and a muscle relaxant, suxamethonium being widely used despite several side-effects. Studies have shown that oral intubation can be facilitated safely and effectively in children after induction of anaesthesia with propofol and alfentanil without a muscle relaxant. Remifentanil is a new, ultra-short acting, selective mu-receptor agonist that is 20-30 times more potent than alfentanil. This clinical study was designed to assess whether combination of propofol and remifentanil could be used without a muscle relaxant to facilitate tracheal intubation in children. METHODS: Forty children (5-10 years) admitted for adenotonsillectomy were randomly allocated to one of two groups to receive remifentanil 2 microg.kg(-1) (Gp I) or remifentanil 3 microg.kg(-1) (Gp II) before the induction of anaesthesia with i.v. propofol 3 mg.kg(-1). No neuromuscular blocking agent was administered. Intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, jaw relaxation, position of vocal cords, degree of coughing and limb movement. Mean arterial pressure (MAP) and heart rate (HR) measured noninvasively before induction of anaesthesia to 5 min after intubation (seven time points). RESULTS: Tracheal intubation was successful in all patients without requiring neuromuscular blocking agent. Intubating conditions were clinically acceptable in 10 of 20 patients (50%) in Gp I compared with 18 of 20 patients (90%) in Gp II (P < 0.05). MAP and HR decreased in both groups after induction of anaesthesia (P < 0.01). Both HR and MAP were significantly lower in Gp II compared with Gp I after tracheal intubation (P < 0.01). No patient in the present study developed bradycardia or hypotension. CONCLUSIONS: We conclude that remifentanil (3 microg.kg(-1)), administered before propofol (3 mg.kg(-1)) provides acceptable tracheal intubating conditions in children, and completely inhibited the increase in HR and MAP associated with intubation.     

瑞芬太尼全麻复合硬膜外麻醉用于开胸手术的临床观察

目的 观察瑞芬太尼全麻复合硬膜外麻醉在开胸手术中的应用效果和安全性. 方法 200例择期行开胸手术患者,ASA Ⅰ～Ⅱ级,按完全随机分组方法分为两组,瑞芬太尼组(R组)与芬太尼组(F组),均采用硬膜外复合气管插管全麻,R组与F组分别采用瑞芬太尼和芬太尼麻醉,观察术前(T0)、气管插管后1 min(T1)、5 min(T2)、切皮(T3)和术后5 min(T4)的血压、心率、血氧饱和度和血中皮质醇水平,记录术后拔管时间及患者的认知能力恢复情况. 结果 两组气管插管反应发生率相比较,F组(14/26,53.8%)明显高于R组(4/26,15.4%)(P<0.05).结论 瑞芬太尼较芬太尼能更好地抑制气管插管引起的应激反应,术后患者较早恢复认知能力,且瑞芬太尼静脉全麻复合胸段硬膜外阻滞能提供有效的镇痛和抑制手术刺激引起的血流动力学反应,术后苏醒快,有利于患者术后排痰,康复快.