The effect of remifentanil on cerebral blood flow velocity in children anesthetized with propofol

BACKGROUND: Cerebrovascular stability and rapid anesthetic emergence are desirable features of a neuroanesthetic regimen. In this randomized crossover study the effect of a low-dose remifentanil infusion on cerebral blood flow velocity (CBFV) in children anesthetized with propofol was evaluated. METHODS: Twenty healthy children aged 1-6 years undergoing urological surgery were enrolled. Following face mask induction with sevoflurane, anesthesia was maintained with a standardized propofol infusion. Rocuronium was used to facilitate tracheal intubation and normothermia, and normocapnia were maintained. All children received a caudal epidural block, and a transcranial Doppler probe was placed to measure middle cerebral artery blood flow velocity (Vmca). Each patient received a remifentanil regimen of 0.5 microg x kg(-1) followed by 0.2 microg x kg(-1) x min(-1) in a predetermined order of remifentanil + propofol or propofol alone. Vmca, mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at equilibrium with and without remifentanil. RESULTS: The combination of remifentanil and propofol caused an 8.1% decrease in MAP (P = 0.0005) and an 11.8% decrease in HR (P < 0.0001) compared with propofol alone. Vmca was not different between the two groups (P = 0.4041). CONCLUSION: The addition of remifentanil to propofol anesthesia in children causes a reduction in MAP and HR without affecting CBFV. This may imply that cerebral blood pressure autoregulation is preserved in children under propofol and remifentanil anesthesia.     

Hemodynamic response to tracheal intubation after vital capacity rapid inhalation induction (VCRII) with different concentrations of sevoflurane

STUDY OBJECTIVE: To evaluate the blood pressure (BP) and heart rate (HR) response to tracheal intubation after vital capacity rapid inhalation induction (VCRII) with four concentrations of sevoflurane followed by nitrous oxide (N2O) 50% and sevoflurane in concentrations administered by clinical judgment. DESIGN: Prospective, randomized study. SETTING: University teaching hospital. PATIENTS: 60 unpremedicated, ASA physical status I and II adult patients undergoing surgery with general anesthesia. INTERVENTIONS: After fentanyl 3 micrograms/kg, VCRII was accomplished with four concentrations of sevoflurane in O2: Group 1 (n = 15): sevoflurane 3%; Group 2 (n = 15): sevoflurane 4%; Group 3 (n = 15): sevoflurane 5%; and Group 4 (n = 15): sevoflurane 6%. At loss of consciousness, rocuronium 0.6 mg/kg was given, and intubation was performed 90 seconds later. Thereafter, anesthesia continued with N2O 50% and sevoflurane. MEASUREMENTS AND MAIN RESULTS: BP and HR measurements were made at the ward (baseline), at loss of consciousness, and just prior to, and each minute after, tracheal intubation during a 5-minute period. The hemodynamic profile among groups was similar, with a slight hypertensive and tachycardic response to intubation. CONCLUSION: VCRII with sevoflurane 3% to 6% following fentanyl 3 micrograms/kg can be considered for blunting the hemodynamic response to tracheal intubation in healthy patients.     

七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度

目的 确定七氟醚麻醉下瑞芬太尼抑制小儿气管插管心血管反应的半数有效血浆靶浓度(Cp<50).方法 择期全麻手术患儿,年龄2～5岁,ASA Ⅰ或Ⅱ级.初始七氟醚吸入浓度为8%,氧流量3 L/min,待患儿意识消失后调整七氟醚吸入浓度,使呼气末七氟醚浓度为2.5%(1 MAC),2 min后采用Minto药代动力学模型靶控输注瑞芬太尼,10 min后进行气管插管.瑞芬太尼血浆靶浓度按序贯法确定,瑞芬太尼血浆靶浓度从6μg/L开始,相邻浓度的比值为1.2,气管插管心血管反应的标准:插管后2 min内MAP和/或HR较插管前升高≥15%.结果 瑞芬太尼抑制气管插管心血管反应的Cp50为3.6μg/L,95%可信区间为3.1～4.0μg/L.结论 七氟醚1 MAC麻醉下瑞芬太尼抑制小儿气管插管心血管反应的Cp50为3.6 μg/L,95%可信区间为3.1～4.0μg/L.     

Remifentanil for modulation of hemodynamics in a patient undergoing laparoscopic resection of pheochromocytoma

The present report monitors the hemodynamic fluctuations in a 63 year-old female patient undergoing laparoscopic resection of right adrenal pheochromocytoma during remifentanil-based anesthesia. Anesthesia was induced with lidocaine 1 mg x kg(-1), propofol 3.5 mg x kg(-1), and cisatracurium 0.2 mg(-1) x kg(-1) and a remifentanil infusion was started at a rate of 1 ug.kg (-1) x min(-1). Anesthesia was then maintained with remifentanil infusion (0.5 microg(-1) x kg(-1) x min), sevoflurane 1-2% (end-tidal) in a mixture of air/oxygen (3:1), and a continuous infusion of cisatracurium. There were no significant changes of BP and HR following tracheal intubation or surgical incision. However, creation of pneumoperitoneum as well as tumor manipulation resulted in a dramatic increase of systolic BP and pulmonary artery pressure, associated with a decrease in cardiac output. These hemodynamic changes were unresponsive to an increase in the remifentanil infusion rate up to 1.5 ug.kg(-1) x min(-1), but were controlled by increasing the concentration of sevoflurane up to 6%, and by a nitroglycerin (NTG) infusion. Ten min after removal of the tumor, and despite discontinuation of the NTG infusion as well as a reduction in the remifentanil infusion and sevoflurane concentration, the BP decreased down to 64/43 mmHg. In conclusion, the present report shows in a patient undergoing laparoscopic resection of adrenal pheochromocytoma that remifentanil does not prevent the severe hypertensive episodes associated with intraperitoneal carbon dioxide insufflation or tumor manipulation. However, it can be titrated to prevent the hemodynamic reflex response to tracheal intubation and surgical stimulation.     

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.     

Comparison of anesthetic maintenance and recovery with propofol versus sevoflurane combined with remifentanil in craniotomy for supratentorial neoplasm

OBJECTIVE: To compare the effectiveness of propofol versus sevoflurane associated with remifentanil on the maintenance of anesthesia and on recovery in patients undergoing elective supratentorial craniotomy. PATIENTS AND METHODS: Prospective randomized trial enrolling 90 patients scheduled for excision of a brain neoplasm. All received an infusion of remifentanil at a dose of 0.5 microg x Kg(-1) x min(-1) until tracheal intubation and then 0.25 microg x Kg(-1) x min(-1) during surgery. Induction was achieved with propofol and anesthesia was maintained with either sevoflurane at a maximum alveolar concentration of 0.4 (45 patients) or propofol by target controlled infusion at a concentration of 2.5 microg x mL(-1) (45 patients, group P). Variables assessed were hemodynamic stability during anesthesia and times and quality of recovery from anesthesia (eye opening, initiation of spontaneous ventilation, extubation, cough reflex, and temporal and spacial orientation 3 minutes after extubation. During the first 24 hours after surgery, pain intensity was evaluated on a verbal visual analog scale (VAS) and the incidence of nausea and vomiting was recorded. RESULTS: Times until eye opening upon request and until extubation were significantly shorter in the sevoflurane group than in the propofol group: 3.7 (SD, 1.2) minutes vs 5 (3.1) minutes, respectively, for eye opening and 6.6 (1.2) minutes vs 8.1 (3.3) minutes for extubation (P<0.01). The incidence of nausea and vomiting was significantly higher in the sevoflurane group (40% vs 13%, respectively, P<0.01). CONCLUSIONS: Combining remifentanil with propofol or with sevoflurane provides satisfactory anesthesia during elective supratentorial craniotomy to remove a brain neoplasm. Hemodynamic stability is appropriate and recovery from anesthesia is rapid.     

Roles of fentanyl and nitroglycerin in prevention of myocardial ischemia associated with laryngoscopy and tracheal intubation in patients undergoing operations of short duration

The purpose of this study was to evaluate intravenous nitroglycerin given during induction of anesthesia as a means for prevention of myocardial ischemia and hemodynamic changes associated with induction, laryngoscopy, and intubation, in patients with stable angina scheduled for vascular operations of moderate duration. Forty-six patients were randomly assigned to receive either fentanyl, 3 micrograms/kg (group 1, n = 6), fentanyl, 8 micrograms/kg (group 2, n = 20), or fentanyl 3 micrograms/kg plus a continuous intravenous nitroglycerin infusion, 0.9 microgram X kg-1 X min-1 (group 3, n = 20), in addition to thiopental-pancuronium anesthetic induction, prior to laryngoscopy and intubation. The criteria for recognizing myocardial ischemia were the following: horizontal or downsloping ST segment depression equal to or greater than 1 mV, and/or ventricular arrhythmia, on CM5 recording. In group 1, myocardial ischemia occurred during laryngoscopy and intubation in four patients, and mean blood pressure (MBP), heart rate, and mean pulmonary wedge pressure (PCWP) increased significantly (P less than 0.05). Despite greater stability in MBP and heart rate in group 2, myocardial ischemia still occurred in four patients (not significantly different from group 1). Nitroglycerin added to low-dose fentanyl (group 3) produced significant reduction in myocardial ischemia (1/20) when compared with group 1 (P less than 0.01), and significantly greater stability in PCWP during laryngoscopy and intubation in comparison to groups 1 and 2. In patients with stable angina undergoing operations of short duration, the use of nitroglycerin infusion and low-dose fentanyl significantly decreases the incidence of myocardial ischemia associated with induction of anesthesia and tracheal intubation.     

静脉注射利多卡因对七氟醚复合瑞芬太尼无肌松药条件下气管插管效果的影响

目的 探讨静脉注射利多卡因对七氟醚复合瑞芬太尼无肌松药条件下气管插管效果的影响.方法气管插管全麻病人75例,年龄18～64岁,ASA分级Ⅰ或Ⅱ级.采用随机数字表法,将病人随机分为3组(n=25),A组:七氟醚+瑞芬太尼1 μg/kg;B组:七氟醚+瑞芬太尼1 μg/kg+利多卡因1 mg/kg;C组:七氟醚+瑞芬太尼2 μg/kg.吸入8%七氟醚2 min时,A组静脉注射瑞芬太尼1μg/kg,B组静脉注射瑞芬太尼1 μg/kg和利多卡因1 mg/kg,C组静脉注射瑞芬太尼2 μg/kg.瑞芬太尼注射完毕后行气管插管.从置入喉镜、声带位置、声带活动、咳嗽反射和体动反应5个方面评价气管插管条件,分为满意、良好和欠佳3个级别,记录各项满意的发生情况.于麻醉诱导前、气管插管前即刻和气管插管后即刻记录MAP和HR.结果 病人均完成气管插管.与A组相比,B组和C组咳嗽反射的满意率升高,C组气管插管前即刻和气管插管后即刻MAP、HR降低(P＜0.05),B组气管插管前即刻和气管插管后即刻MAP和HR差异无统计学意义(P＞0.05);B组咳嗽反射的满意率较C组升高(P＜0.05).气管插管期间,C组有3例发生低血压,1例心动过缓,A组和B组均未见低血压或心动过缓发生.结论 七氟醚复合瑞芬太尼用于无肌松药条件下气管插管时,静脉注射利多卡因1mg/kg不仅可优化气管插管条件,还可降低瑞芬太尼用量.

Abstract：

Objective To investigate the effect of intravenous lidocaine on the efficacy of sevoflurane combined with remifentanil for tracheal intubation without neuromuscular relaxants. Methods Seventy-five ASA Ⅰor Ⅱ patients, aged 18-64 yr, scheduled for elective surgery, needing tracheal intubation under general anesthesia, were randomly divided into 3 groups ( n = 25 each) : sevoflurane + remifentanil 1 μg/kg group (group A) ;sevoflurane + remifentanil 1 μg/kg + lidocaine 1 mg/kg group (group B); sevoflurane + remifentanil 2 μg/kg group (group C) . Two minutes after inhalation of 8% sevoflurane for anesthesia induction, remifentanil 1 μg/kg, remifentanil 1 μg/kg + lidocaine 1 mg/kg, and remifentanil 2 μg/kg were injected intravenously in groups A, B and C respectively. Tracheal intubation was performed after completion of remifentanil injection. Intubating conditions were assessed based on ease of laryngoscopy, position of vocal cords, activity of vocal cords, degree of coughing and limb movement. MAP and HR were also recorded before induction and immediately before and after intubation. Results Tracheal intubations were successful in all patients. The satisfactory rates of coughing were significantly higher in groups B and C, and MAP and HR were significantly lower immediately before and after intubation in group C than in group A ( P ＜ 0.05) . The satisfactory rate of coughing was significantly higher in group B than in group C ( P ＜ 0.05) . During intubation, 3 cases developed hypotension and 1 case bradycardia in group C. Conclusion When sevoflurane combined with remifentanil is used for tracheal intubation without neuromuscular relaxants, intravenous lidocaine 1 mg/kg can not only improve intubating conditions, but also decrease the consumption of remifentanil.     

Propofol decreases cerebral blood flow velocity in anesthetized children

PURPOSE: Propofol, by virtue of its favourable pharmacokinetic profile, is suitable for maintenance of anesthesia by continuous infusion during neurosurgical procedures in adults. It is gaining popularity for use in pediatric patients. To determine the effects of propofol on cerebral blood flow in children, middle cerebral artery blood flow velocity (Vmca) was measured at different levels of propofol administration by transcranial Doppler (TCD) sonography. METHODS: Twelve ASA I or II children, aged one to six years undergoing elective urological surgery were randomized to receive one of two propofol dosing regimens. Half of the patients received propofol in an escalating fashion, initially targeting an estimated steady-state serum concentration of 3 microg x mL-1, which was then doubled. The other half received propofol designed initially to target the high concentration followed by the lower one. In each child anesthesia was induced and maintained with propofol according to the protocol, rocuronium was given to facilitate tracheal intubation, and a caudal epidural block was performed. A TCD probe was placed appropriately to measure Vmca. Cerebral blood flow velocity (CBFV), mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at both levels of propofol administration. RESULTS: Twelve patients were studied. At the higher estimated target serum propofol concentration there were significant decreases in Vmca (17%, P < 0.001), MAP (6%, P < 0.002) and HR (8%, P < 0.05) when compared to the lower targeted concentration. CONCLUSION: This study shows that a higher rate of propofol infusion is associated with lower CBFV and MAP values in children. Propofol's cerebral vasoconstrictive properties may be responsible for this finding.     

Clinical usefulness of remifentanil

Anesthesia with remifentanil can be induced either with slow bolus administration (1 microg x kg(-1) for over 60 sec) or with starting the continuous infusion (0.5-1 microg x kg(-1) x hr(-1)) combined with a standard hypnotic agent (i.e. propofol, thiamylal, sevoflurane or isoflurane). According to the patient's requirement observing hemodynamics, the infusion rate of remifentanil should be titrated after tracheal intubation. Because of the rapid onset and short duration of its action, the infusion rate can be increased or decreased safely. Remifentanil is an effective agent in obtunding the stress response to tracheal intubation and surgery. Due to its synergistic effect with hypnotic agents, sevoflurane, isoflurane or propofol, it should be reduced carefully to prevent excessive depth of anesthesia. BIS values should be monitored closely. Remifentanil seems to be as potent as fentanyl. Prior to emergence from general anesthesia using remifentanil, postoperative pain management should be considered. NSAIDs or a long acting opioid could be administered.     

Effect of tracheal intubation or laryngeal mask airway insertion on intraocular pressure using balanced anesthesia with sevoflurane and remifentanil.

STUDY OBJECTIVES: To study the effect of tracheal intubation or laryngeal mask airway (LMA) insertion on intraocular pressure (IOP) in strabismus patients undergoing balanced anesthesia with sevoflurane and remifentanil. DESIGN: Open, prospective, randomized study. SETTING: Tertiary care academic medical institution. PATIENTS: 40 adult ASA physical status I and II patients scheduled for elective strabismus surgery. INTERVENTION: Patients were randomized to receive either tracheal intubation or LMA insertion following mask induction with sevoflurane in combination with IV remifentanil. MEASUREMENTS: Intraocular pressure, mean arterial pressure (MAP), and heart rate (HR) were measured before induction, immediately following induction, and after airway insertion. MAIN RESULTS: Intraocular pressure after tracheal intubation or LMA insertion did not differ significantly from preoperative baseline values. Mean arterial pressure and HR did not significantly differ between groups at any time point. CONCLUSIONS: Remifentanil and sevoflurane are not associated with an increase in IOP response during tracheal intubation or LMA insertion above baseline in healthy patients undergoing ophthalmic surgery.     

Lightwand intubation does not reduce the increase in intraocular pressure associated with tracheal intubation.

OBJECTIVE: To evaluate the changes in hemodynamic variables and intraocular pressure (IOP) after tracheal intubation using either lightwand or direct-vision laryngoscopy techniques. DESIGN: Prospective, randomized study. SETTING: Inpatient anesthesia at a University Anesthesia Department. PATIENTS: 50 normotensive, ASA physical status I and II patients, without ocular or cardiovascular diseases, and with a Mallampati score no greater than 2. INTERVENTIONS: After intravenous (i.v.) midazolam premedication (0.05 mg.kg-1), general anesthesia was induced with fentanyl (1 microgram.g-1) and thiopental sodium (5 mg.g-1) followed by vecuronium bromide (0.1 mg.g-1), then patients were randomly allocated to receive either the lightwand (Trachlight, n = 25) or direct-vision laryngoscopy (Laryngoscopy, n = 25) intubating techniques. General anesthesia was maintained with 1% isoflurane and 60% nitrous oxide in oxygen mixture for 5 minutes. MEASUREMENTS AND MAIN RESULTS: Baseline hemodynamic variables were recorded 10 minutes after i.v. premedication, and then every minute after tracheal intubation. Intraocular pressure measurements were performed by means of a computerized indentation tonometer after general anesthesia induction and then 1 and 5 minutes after tracheal intubation. In both groups, mean arterial blood pressure and heart rate increased from baseline, without differences between the two groups. One minute after intubation, IOP increased in both groups: the mean percentage increase was 32% in the Laryngoscopy group and 16% in the Trachlight group. However, this difference was not statistically significant. Five minutes after intubation, IOP decreased to baseline values in both groups. CONCLUSION: We conclude that in healthy patients without ocular disease, using a lightwand intubating technique does not reduce the hemodynamic responses and increase in IOP associated with tracheal intubation as compared with conventional direct-vision laryngoscopy.     

Clinical comparison of either small doses of fentanyl or remifentanil for blunting cardiovascular changes induced by tracheal intubation

BACKGROUND: To compare in a prospective, randomized study the effects on cardiovascular changes after tracheal intubation produced by small doses of either remifentanil or fentanyl. METHODS: With Ethical Committee approval, after intravenous midazolam premedication (0.05 mg.kg-1), 30 normotensive, ASA physical status I-II patients, without cardiovascular or respiratory diseases, and with a Mallampati score < 2, were randomly allocated to receive an intravenous bolus of either 3 micrograms.kg-1 fentanyl (n = 15) or 1 microgram.kg-1 remifentanil (n = 15) infused over 60 sec and followed by a 0.15 microgram.kg-1.min-1 continuous intravenous infusion. General anesthesia was then induced with propofol (2 mg.kg-1), followed by atracurium besilate (0.5 mg.kg-1) to facilitate tracheal intubation. Following intubation, the lungs were ventilated mechanically using a 60% nitrous oxide in oxygen mixture with a 1% inspired fraction of sevoflurane. Arterial blood pressure and heart rate were recorded before anesthesia induction (baseline), one minute after induction of anesthesia, immediately after tracheal intubation and every minute for the first five minutes after intubation. RESULTS: Systolic arterial blood pressure values were significantly higher in the Fentanyl than in the Remifentanil group patients from 2 to 5 min after tracheal intubation (p < 0.01), while no differences were observed between the two groups in either diastolic arterial blood pressure or heart rate values. Four patients in the Remifentanil group (26%) but only one patient in the Fentanyl group (7%) showed systolic blood pressure values < 90 mmHg during the study period (p = not significant); however, the observed decreases in systolic arterial blood pressure values were transient and did not require treatment for any subject. CONCLUSION: We conclude that in healthy normotensive patients, the control of cardiovascular responses to tracheal intubation obtained with a 1 microgram.kg-1 loading dose of remifentanil is more effective than that provided by a 3 micrograms.kg-1 bolus of fentanyl, with the advantage of no risks for postoperative respiratory depression.     

Intraocular pressure more reduced during anesthesia with propofol than with sevoflurane: both combined with remifentanil

BACKGROUND: Short-acting anesthetic agents are suitable and commonly used in ocular surgery. Propofol and remifentanil are known to reduce intraocular pressure (IOP), but no information is available regarding the effects of sevoflurane combined with remifentanil on IOP. METHODS: Therefore, a prospective, randomized study was conducted to compare the effects on IOP of two different anesthetic techniques: one based on a total intravenous anesthesia with propofol (Group P, bolus 1.5-2.0 mg/kg, maintenance 3.0-7.0 mg/kg/h); and the other based on sevoflurane (Group S, inhalational induction, end-tidal concentration 0.7-1.2 vol.%). An infusion of remifentanil (10 microg/kg/h) was used with both techniques. In ASA I-III patients with normal IOP undergoing elective cataract surgery, using an applanation tonometer, IOP was measured contralateral to the operated eye at nine predefined time points before, during and after anesthesia. RESULTS: The two groups (n=20 each) were comparable with regard to demographic data and hemodynamic variables. Baseline IOP was 14.2+/-2.8 mmHg (Group P) and 14.1+/-2.4 mmHg (Group S; NS). During and following the induction of anesthesia, IOP was reduced in both groups. Intraocular pressure was significantly lower in Group P (6.0+/-3.2 mmHg) than in Group S (8.9+/-3.4 mmHg) during the induction of anesthesia. CONCLUSION: In patients undergoing cataract surgery under general anesthesia with tracheal intubation, anesthetic regimens with propofol as well as with sevoflurane, both combined with remifentanil, decrease IOP significantly. The decrease in IOP was significantly more pronounced in the propofol group than in the sevoflurane group.     

Intravenous anesthesia with propofol in intracranial surgery]

OBJECTIVES: To analyze the repercussions of intravenous anesthesia with propofol as the single hypnotic drug on intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and also to study the time until recovery from anesthesia and to tracheal extubation as well as intraoperative hemodynamic changes in patients undergoing surgery to remove a supratentorial brain tumor. PATIENTS AND METHODS: Twenty-three ASA I/II patients scheduled for exeresis of a supratentorial brain tumor were studied. A fiberoptic sensor placed in direct contact with the dura mater was used to measure ICP. Anesthetic induction was achieved with propofol (2 mg/kg). Propofol (12 and 9 mg/kg/h for 10 min and 6 mg/kg/h throughout the rest of the operation) was used for maintenance. Mean arterial pressure (MAP), heart rate (HR), ICP and CPP were recorded at baseline and 1, 2, 3 and 4 min after induction, during laryngoscopy and tracheal intubation; 1, 3, 5, 10, 15 and 20 min after tracheal intubation (L + 1, L + 3, L + 5, L + 10, L + 15, L + 20), upon placement of a craniostat; upon skin incision; upon withdrawal of propofol perfusion; and during extubation. The following variables were recorded after awakening: time until eye opening after receiving a verbal command, time until extubation and time until orientation. Analysis of variance for repeated measures (ANOVA) was performed on the results. RESULTS: MAP decreased significantly from baseline at the following times: during the post-induction period, upon placement of the craniostat, upon skin incision and when the propofol infusion was switched off. HR increased significantly during laryngoscopy and at the following moments: intubation, post intubation (L + 1, L + 3, L + 5), craniostat placement, and extubation. ICP was lower throughout the surgical period except during laryngoscopy, when this variable increased significantly. CPP decreased significantly after induction and returned to baseline after intubation. CPP was significantly higher after surgery. Recovery times after weaning from propofol infusion until eye opening in response to an order and until orientation were 13 +/- 3 and 22 +/- 4 min, respectively. The mean interval between withdrawal of propofol until extubation was 18 min. CONCLUSIONS: Intravenous anesthesia with propofol in intracranial surgery (supratentorial tumors) affords hemodynamic stability and lowers ICP except during laryngoscopy. Early recovery from anesthesia allows for neurological assessment and vigilance during the immediate postoperative period.     

不同血浆靶浓度瑞芬太尼对患儿吸入七氟烷诱导气管插管最低肺泡有效浓度的影响

目的 评价不同血浆靶浓度瑞芬太尼对患儿吸入七氟烷诱导气管插管最低肺泡有效浓度(MAC)的影响.方法 择期全麻患儿126例,年龄3～8岁,ASAⅠ或Ⅱ级,随机分为4组,对照组(C组,n=30);R1组(n=30)、R2组(n=30)和R3组(n=36)瑞芬太尼血浆靶浓度分别为1、2、3 ng/ml.均吸入5%七氟烷行麻醉诱导,睫毛反射消失后鼻腔置入导管连接气体分析仪,建立静脉通路,注射阿托品0.01 mg/kg,R1-3 组靶控输注瑞芬太尼.C组注射阿托品、R1-3组瑞芬太尼血浆浓度与效应室浓度达平衡后,采用改良序贯法进行试验,初始呼气末七氟烷浓度均为3.0%,相邻浓度比值为1.2,七氟烷呼气末浓度达到预定值并维持10 min后行气管插管.气管插管条件满意的标准:气管插管条件评分为6分.计算每组七氟烷MAC,并观察不良反应的发生情况.结果 C组、R1-3组患儿吸入七氟烷诱导气管插管的MAC分别为5%、3%、2%、1%,依次降低(P<0.01);所有患儿均无心动过缓、低血压等发生,R2组3例、R3组8例患儿因下颌松弛度差致喉镜无法置人或声门关闭,静脉注射罗库溴铵完成气管插管.结论 瑞芬太尼1 ng/ml可降低患儿吸入七氟烷诱导气管插管的最低肺泡有效浓度,且不良反应少.     

The effects of remifentanil and alfentanil-based total intravenous anesthesia (TIVA) on the endocrine response to abdominal hysterectomy

STUDY OBJECTIVE: To compare the effects of remifentanil with alfentanil as a part of total intravenous anesthesia (TIVA) on plasma concentrations of cortisol, insulin, and glucose, and hemodynamic responses in patients undergoing abdominal hysterectomy. DESIGN: Randomized, double-blind study. SETTING: University hospital. PATIENTS: 24 ASA physical status I female patients scheduled for abdominal hysterectomy. INTERVENTIONS: Premedicated patients were randomly allocated to receive either remifentanil-propofol (Group R) or alfentanil-propofol (Group A). The loading dose of the study drug was administered over 60 seconds (remifentanil l microg kg(-l) or alfentanil 10 microg kg(-l)) followed by a continuous infusion (remifentanil 0.2 microg kg(-l) min(-l) or alfentanil 0.5 microg kg(-l) min(-l)). In both groups, propofol was administered until loss of consciousness and maintained with a propofol infusion rate of 100 microg kg(-l) min(-l). After induction of anesthesia, all patients were manually ventilated by mask with O2-air mixture for 20 minutes. Then rocuronium 0.6 mg kg(-l) was given for tracheal intubation. MEASUREMENTS: Mean arterial pressure (MAP) and heart rate (HR) were recorded. Plasma concentrations of cortisol, insulin, and glucose were measured during anesthesia and in the recovery room. MAIN RESULTS: In Group R, MAP and HR were lower after tracheal intubation and skin incision than in Group A (p < 0.05). Plasma cortisol concentrations decreased from baseline values at 20 minutes after induction, after tracheal intubation, and skin incision in Group R (p < 0.001). Plasma concentrations of cortisol and glucose increased from baseline values at 30 minutes after skin incision and continued to increase in both groups (p = 0.001). Plasma concentrations of cortisol, insulin, and glucose did not differ between groups at all sampling times. CONCLUSION: Remifentanil provided better hemodynamic stability than alfentanil during anesthesia and surgery. However, both remifentanil and alfentanil had similar effects on the stress endocrine response to abdominal hysterectomy.     

双氯芬酸钠栓对七氟醚复合瑞芬太尼麻醉恢复期患儿的镇痛效应

目的 评价双氯芬酸钠栓对七氟醚复合瑞芬太尼麻醉恢复期患儿的镇痛效应.方法 择期行扁桃体切除和(或)腺样体摘除手术患儿40例,年龄2～10岁,ASA Ⅰ或Ⅱ级,随机分为2组(n=20):对照组(C组)和双氯芬酸钠栓组(D组).吸入l%～3%七氟醚和静脉输注瑞芬太尼0.05～0.1 μg·kg-1·min-1维持麻醉,静脉输注罗库溴铵5～10μg·kg-1·min-1维持肌松.气管插管后,D组将双氯芬酸钠栓1 mg/kg塞至距患儿肛门2 cm处,C组不做任何处理.拔除气管导管即刻采用Ramsay镇静评分评价镇静程度,采用躁动评分评价躁动程度.结果 与C组比较,D组镇静效果好,躁动程度轻(P<0.01).结论 气管插管后经直肠给予双氯芬酸钠栓l mg/kg对七氟醚复合瑞芬太尼麻醉恢复期患儿产生显著的镇痛效应,有助于避免躁动的发生.     

Hemodynamic and catecholamine response to tracheal intubation: direct laryngoscopy compared with fiberoptic intubation

STUDY OBJECTIVE: To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberoptic bronchoscopy technique. DESIGN: Randomized, prospective study. SETTING: Operating rooms in a teaching hospital. PATIENTS: 51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia. INTERVENTIONS: Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used. MEASUREMENTS: Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and 1 and 5 minutes after intubation. MAIN RESULTS: Duration of intubation was shorter in the direct laryngoscopy group (16.9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine levels did not increase after intubation and did not correlate with the hemodynamic changes. CONCLUSIONS: The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine levels do not correlate with the hemodynamic changes.     

Pulse wave velocity can predict hemodynamic responses to induction of anesthesia and tracheal intubation

BACKGROUND: The degree of aortic stiffness can be evaluated by noninvasive measurement of pulse wave velocity (PWV). We investigated hemodynamic responses to induction of anesthesia and tracheal intubation, and hypothesized that preoperative measurement of PWV might predict these responses. METHODS: PWV was measured before operation by using automatic PWV measurement device. Patients were anesthetized with fentanyl (1 microg x kg(-1)) and propofol (target controlled infusion at 2.5 microg x ml(-1)), and tracheal intubation was facilitated with vecuronium (1.5 mg x kg(-1)). Hemodynamic data were recorded from the start of anesthesia to 5 minutes after the tracheal intubation. RESULTS: Twenty patients completed the study. There was a significant correlation between PWV and percent changes in systolic blood pressure during anesthesia induction. However, a significant correlation between PWV and percent changes in systolic blood pressure after tracheal intubation was found only in the patients without antihypertensive medications. CONCLUSIONS: Preoperative PWV measurement was useful to predict hemodynamic responses to induction of anesthesia and tracheal intubation.