The use of esmolol as an alternative to remifentanil during desflurane anesthesia for fast-track outpatient gynecologic laparoscopic surgery

We compared esmolol and remifentanil infusions with respect to their effect on intraoperative hemodynamic stability and early recovery after outpatient laparoscopic surgery when administered as IV adjuvants during desflurane anesthesia. After premedication with midazolam 2 mg IV, anesthesia was induced with propofol 2 mg. kg(-1) IV in combination with either esmolol 1 mg. kg(-1) IV (n = 27) or remifentanil 1 microg. kg(-1) IV (n = 26) and succinylcholine 1 mg. kg(-1) IV according to a randomized, double-blinded protocol. Anesthesia was initially maintained with desflurane 2.5% (subsequently titrated to maintain an electroencephalogram-bispectral index value of 60) and nitrous oxide 65% in oxygen. Before skin incision, an infusion of either esmolol (5 microg. kg(-1). min(-1)) or remifentanil (0.05 microg. kg(-1). min(-1)) was started and titrated to maintain the heart rate within 25% of the baseline value. Mivacurium, 0.04 mg/kg IV, bolus doses were administered to maintain a stable peak inspiratory pressure. Esmolol (12.8 +/- 13.1 microg. kg(-1). min(-1)) and remifentanil (0.04 +/- 0.02 microg. kg(-1). min(-1)) infusions were equally effective in maintaining a stable heart rate during these laparoscopic procedures. Although the mivacurium requirement was larger in the Esmolol group (7 +/- 5 vs 3 +/- 4 mg), the Esmolol group reported a smaller incidence of postoperative nausea and vomiting (4% vs 35%). Both drugs were associated with frequent "postanesthesia care unit bypass" rates (78-81%), short times to "home readiness" (119-120 min), excellent patient satisfaction (81-85%), and rapid resumption of normal activities (2.6-3.2 d). Fast-tracked patients were ready for discharge home significantly earlier (112 +/- 46 vs 151 +/- 50 min). We concluded that esmolol infusion is an acceptable alternative to remifentanil infusion for maintaining hemodynamic stability during desflurane-based fast-track anesthesia for outpatient gynecologic laparoscopic surgery.     

The effect of intraoperative use of esmolol and nicardipine on recovery after ambulatory surgery

There is controversy regarding the optimal technique for maintaining hemodynamic stability during anesthesia. We designed this prospective, randomized, double-blinded study to test the hypothesis that the technique used for maintaining hemodynamic stability during general anesthesia can influence recovery after ambulatory surgery. Forty-five healthy consenting women undergoing gynecologic laparoscopy procedures were randomly assigned to 1 of 3 treatment groups: Group 1 (control, n = 15) received normal saline 5 mL and 1 mL, followed by a saline infusion at a rate of 0.005 mL x kg(-1) x min(-1); Group 2 (n = 15) received esmolol 50 mg and saline 1 mL, followed by an esmolol infusion 5 microg x kg(-1) x min(-1); and Group 3 (n = 15) received esmolol 50 mg and nicardipine 1 mg, followed by an esmolol infusion 5 microg x kg(-1) x min(-1). The study drugs were administered after the induction of anesthesia with fentanyl 1.5 microg/kg, and propofol 2 mg/kg I.V. Tracheal intubation was facilitated with vecuronium 0.12 mg/kg I.V. Anesthesia was initially maintained with desflurane 2% end-tidal and N(2)O 67% in oxygen in all 3 groups. During surgery, the mean arterial blood pressure (MAP) was maintained within +/-15% of the baseline value by varying the study drug infusion rate and the inspired concentration of desflurane. In addition to MAP and heart rate values, electroencephalogram bispectral index values were recorded throughout the perioperative period. Recovery times and postoperative side effects were assessed. Compared with the control group, adjunctive use of esmolol and nicardipine attenuated the increase in heart rate (in Group 2) and MAP (in Group 3) after tracheal intubation. Furthermore, the use of an esmolol infusion as an adjunct to desflurane to control the acute autonomic responses during the maintenance period significantly decreased emergence times (4 +/- 2 versus 7 +/- 4 min), decreased the need for postoperative opioid analgesics (43% versus 80%), and reduced the time to discharge (209 +/- 89 versus 269 +/- 100 min). We conclude that the adjunctive use of esmolol alone or in combination with nicardipine during the induction of anesthesia reduced the hemodynamic response to tracheal intubation. Furthermore, use of an esmolol infusion as an adjuvant to desflurane-N(2)O anesthesia for controlling the acute hemodynamic responses during the maintenance period improved the recovery profile after outpatient laparoscopic surgery. IMPLICATIONS: The adjunctive use of the beta-adrenergic blocker esmolol to control the acute sympathetic responses during desflurane-based anesthesia provided a more rapid awakening from anesthesia, reduced the postoperative opioid analgesic requirement, and decreased the time to discharge home after ambulatory laparoscopic surgery.     

Fast-tracking after immersion lithotripsy: general anesthesia versus monitored anesthesia care

Both monitored anesthesia care (MAC) and general anesthesia (GA) offer advantages over epidural anesthesia for immersion lithotripsy. We compared propofol-based MAC and desflurane-based GA techniques for outpatient lithotripsy. After receiving midazolam 2 mg IV, 100 subjects were randomly assigned to one of two anesthetic treatment groups. In the MAC group, propofol 50-100 microg. kg(-1). min(-1) IV was titrated to maintain an observer's assessment of alertness/sedation score of 2-3 (5 = awake/alert to 1 = asleep). Remifentanil 0.05 microg.kg(-1). min(-1) IV supplemented with 0.125 microg/kg IV boluses, was administered for pain control. In the GA group, anesthesia was induced with propofol 1.5 mg/kg IV and remifentanil 0.125 microg/kg IV and maintained with desflurane (2%-4% inspired) and nitrous oxide (60%). Tachypnea (respiratory rate >20 breaths/min) was treated with remifentanil 0.125 microg/kg IV boluses. In the GA group, droperidol (0.625 mg IV) was administered as a prophylactic antiemetic. Recovery times and postoperative side effects were assessed up to 24 h after the procedure. Compared with MAC, the use of GA reduced the opioid requirement and decreased movements and episodes of desaturation (<90%) during the procedure. Although the GA group took longer to return to an observer's assessment of alertness/sedation score of 5, discharge times were similar in both groups. We conclude that GA can provide better conditions for outpatient immersion lithotripsy than MAC sedation without delaying discharge. IMPLICATIONS: A desflurane-based general anesthetic technique using the cuffed oropharyngeal airway device was found to be a highly acceptable alternative to propofol-based monitored anesthesia care sedation for outpatient immersion lithotripsy.     

Remifentanil administration during monitored anesthesia care: are intermittent boluses an effective alternative to a continuous infusion?

This randomized, double-blind study was designed to evaluate the analgesic effectiveness and respiratory stability of remifentanil when administered as intermittent bolus injections, a variable-rate infusion, or a combination of a constant basal infusion supplemented with intermittent boluses during monitored anesthesia care (MAC). Forty-five patients undergoing extracorporeal shock wave lithotripsy (ESWL) procedures were randomly assigned to one of the three modes of remifentanil administration. All patients received midazolam 2 mg i.v., followed by a propofol infusion at 50 microg x kg(-1) x min(-1). Two minutes before administering a series of test shock waves: Group I received a remifentanil infusion of 0.1 microg x kg(-1) x min(-1), and a saline bolus (5 mL); Group II received a saline infusion and a remifentanil bolus (25 microg in 5 mL); and Group III received a remifentanil infusion of 0.05 microg x kg(-1) x min(-1), and a remifentanil bolus (12.5 microg in 5 mL). The average pain intensity was scored on an 11-point scale, with 0 = no pain to 10 = severe pain. During the ESWL procedure, pain was treated by increasing the study drug infusion rate by 25%-50% and administering 5-mL bolus injections of the study medication in Groups I (saline) and II (remifentanil 25 microg). In Group III, intermittent 5-mL boluses (remifentanil 12.5 microg) were administered as needed. Patients in Groups II and III reported lower pain scores in response to the test shocks. Significantly more remifentanil was administered in Group I (379 +/- 207 microg) than in Group II (201 +/- 136 microg). However, more interventions were required for the treatment of intraoperative pain in the intermittent bolus group (Group II). When remifentanil is administered as the analgesic component of a MAC technique, these data support the use of intermittent bolus doses (12.5-25 microg) alone or in combination with a basal infusion (0.05 microg x kg(-1) x min(-1)) as alternatives to a variable-rate continuous infusion. IMPLICATIONS: In this study, three different modes of remifentanil administration were used during monitored anesthesia care for extracorporeal shock wave lithotripsy procedures. These results suggest that using intermittent bolus injections of remifentanil (25 microg) or a continuous infusion (0.05 microg x kg(-1) x min(-1)) supplemented with intermittent bolus (12.5 microg) injections may be more effective than a variable-rate infusion of remifentanil during propofol sedation.     

Comparison of adenosine and remifentanil infusions as adjuvants to desflurane anesthesia

BACKGROUND: Because adenosine has been alleged to produce both anesthetic and analgesic sparing effects, a randomized, double-blinded study was designed to compare the perioperative effects of adenosine and remifentanil when administered as intravenous adjuvants during general anesthesia for major gynecologic procedures. METHODS: Thirty-two women were assigned randomly to one of two drug treatment groups. After premedication with 0.04 mg/kg intravenous midazolam, anesthesia was induced with 2 micro/kg intravenous fentanyl, 1.5 mg/kg intravenous propofol, and 0.6 mg/kg intravenous rocuronium, and maintained with desflurane, 2%, and nitrous oxide, 65%, in oxygen. Before skin incision, an infusion of either remifentanil (0.02 microg x kg(-1) x min(-1)) or adenosine (25 microg x kg(-1) x min(-1)) was started and subsequently titrated to maintain systolic blood pressure, heart rate, or both within 10-15% of the preincision values. RESULTS: Adenosine and remifentanil infusions were effective anesthetic adjuvants during lower abdominal surgery. Use of adenosine (mean +/- SEM, 166+/-17 microg x kg(-1) x min(-1)) was associated with a significantly greater decrease in systolic blood pressure and higher heart rate values compared with remifentanil (mean +/- SEM, 0.2+/-0.03 microg kg(-1) x min(-1)). Total postoperative opioid analgesic use was 45% and 27% lower in the adenosine group at 0-2 h and 2-24 h after surgery, respectively. CONCLUSIONS: Adjunctive use of a variable-rate infusion of adenosine during desflurane-nitrous oxide anesthesia was associated with acceptable hemodynamic stability during the intraoperative period. Compared with remifentanil, intraoperative use of adenosine was associated with a decreased requirement for opioid analgesics during the first 24 h after operation.     

Effects of propofol and remifentanil on phrenic nerve activity and nociceptive cardiovascular responses in rabbits.

BACKGROUND: The effects of propofol, remifentanil, and their combination on phrenic nerve activity (PNA), resting heart rate (HR), mean arterial pressure (MAP), and nociceptive cardiovascular responses were studied in rabbits. METHODS: Basal anesthesia and constant blood gas tensions were maintained with alpha-chloralose and mechanical ventilation. PNA, HR, MAP, and maximum changes in HR and MAP (deltaHR, deltaMAP) evoked by electrical nerve stimulation of tibial nerves were recorded. The comparative effects were observed for propofol at infusion rates from 0.05 to 3.2 mg x kg(-1) x min(-1) (group I) and remifentanil from 0.0125 to 12.8 microg x kg(-1) x min(-1) alone (group II), and during constant infusions of propofol at rates of 0.1 and 0.8 mg x kg(-1) x min(-1) (groups III and IV, respectively). Finally, the effect of remifentanil on propofol blood levels was observed (group V). RESULTS: The infusion rates for 50% depression (ED50) of PNA, deltaHR, and deltaMAP were 0.41, 1.32, and 1.58 mg x kg-(1) x min(-1) for propofol, and 0.115, 0.125, and 1.090 microg x kg(-1) x min(-1) for remifentanil, respectively. The ratios for the ED50 values of deltaHR and deltaMAP to PNA were 3.2 and 3.9 for propofol, and 1.1 and 9.5 for remifentanil, respectively. Analysis of the expected and observed responses and isobologrms showed that although their combined effects on PNA, resting HR, and MAP, and deltaMAP were synergistic for deltaHR, they were merely additive. Remifentanil had no effect on propofol blood levels. CONCLUSION: PNA was abolished by propofol and remifentanil, alone and in combination, before significant depression of nociceptive pressor responses occurred. Their combined effects on PNA, HR, MAP, and deltaMAP are greater than additive, ie., synergistic. Unlike propofol, remifentanil obtunded pressor responses more than the resting circulation.     

Bisulfite-containing propofol: is it a cost-effective alternative to Diprivan for induction of anesthesia?

Propofol (Diprivan(TM); AstraZeneca, Wilmington, DE) is a commonly used drug for the induction of general anesthesia in the ambulatory setting. With the availability of a new bisulfite-containing generic formulation of propofol, questions have arisen regarding its cost effectiveness and safety compared with Diprivan(TM). Two hundred healthy outpatients were randomly assigned, according to a double-blinded protocol, to receive either Diprivan(TM) or bisulfite-containing propofol 1.5 mg/kg IV as part of a standardized induction sequence. Maintenance of anesthesia consisted of either desflurane (4%-8% end-tidal) or sevoflurane (1%-2% end-tidal) in combination with a remifentanil infusion (0.125 microg x kg(-1) x min(-1) IV). Patient assessments included pain on injection, induction time, hemodynamic and bispectral electroencephalographic changes during induction, emergence time, and incidence of postoperative nausea and vomiting. The two propofol groups were comparable demographically, and the induction times and bispectral index values during the induction were also similar. However, the bisulfite-containing formulation was associated with less severe pain on injection (5% vs 11%), with fewer patients recalling pain on injection after surgery (38% vs. 51%, P<0.05). None of the patients manifested allergic-type reactions after the induction of anesthesia. The acquisition cost (average wholesale price in US dollars) of a 20-mL ampoule of Diprivan(TM) was $15 compared with $13 for the bisulfite-containing propofol formulation. Therefore, we concluded that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM) for the induction of outpatient anesthesia. Implications: Bisulfite-containing propofol and Diprivan(TM) (AstraZeneca, Wilmington, DE) were similar with respect to their induction characteristics; however, the generic formulation was associated with a smaller incidence of injection pain. Assuming that the drug costs are similar, these data suggest that the bisulfite-containing formulation of propofol is a cost-effective alternative to Diprivan(TM).     

Anesthesia management with short acting agents for bilateral pheochromocytoma removal in a 12-year-old boy

A 12-year-old boy with bilateral adrenal pheochromocytoma pretreated with furosemide, nifedipine, prazosin, and propranolol underwent surgical removal of the tumors. General anesthesia with desflurane, remifentanil infusion and thoracic epidural analgesia was performed. To control the blood pressure (BP), remifentanil up to 1 microg.kg(-1).min(-1) infusion rate, sodium nitroprusside, and esmolol infusions were administered successfully. Following the ligation of the adrenal veins, hemodynamic parameters were stable and neither inotropic support nor corticosteroid replacement was required. We concluded that remifentanil-based anesthesia combined with low-dose desflurane and thoracic epidural analgesia may reduce the need for vasoactive drugs in the anesthesia management of pheochromocytoma. This combination may not prevent the hemodynamic fluctuations during tumor manipulation, but appears to facilitate a rapid and stable postoperative recovery.     

A retrospective analysis of a remifentanil/propofol general anesthetic for craniotomy before awake functional brain mapping

We performed this study to summarize drug dosing, physiologic responses, and anesthetic complications from an IV general anesthetic technique for patients undergoing craniotomy for awake functional brain mapping. Review of 98 procedures revealed "most rapid" IV infusion rates for remifentanil 0.05, 0.05-0.09 microg x kg(-1) x min(-1) and propofol 115, 100-150 microg x kg(-1) x min(-1). The infusions lasted for 78, 58-98 min. Intraoperative emergence from general anesthesia was 9 (6-13) min after discontinuing IV infusions to allow for brain mapping and was independent of infusion duration and duration of craniotomy before mapping. Spontaneous ventilation was generally satisfactory during drug infusion, as evidenced by Sao(2) = 95% (92%-98%) and Paco(2) = 50 (47-55) mm Hg. However, we recorded at least one 30-s epoch of apnea in 69 of 96 patients. Maximum systolic arterial blood pressure was 150 (139-175) mm Hg and minimal systolic arterial blood pressure was 100 (70-150) mm Hg during drug infusion. Three patients experienced intraoperative seizures. Two patients did not tolerate the awake state and required reinduction of general anesthesia. No patients required endotracheal intubation or discontinuation of surgery. This general anesthetic technique is effective for craniotomy with awake functional brain mapping and offers an alternative to continuous wakefulness or other IV sedation techniques. IMPLICATIONS: An IV general anesthetic technique using remifentanil and propofol is an effective method allowing for reliable emergence for intraoperative awake functional brain mapping during craniotomy.     

Fast-track cardiac anesthesia: a comparison of remifentanil plus intrathecal morphine with sufentanil in a desflurane-based anesthetic

OBJECTIVE: To compare the effects of an intravenous remifentanil infusion plus intrathecal morphine with intravenous sufentanil infusion with respect to intraoperative hemodynamic variables, extubation times, and recovery profiles when administered as part of a desflurane-based fast-track anesthetic regimen for cardiac surgery. DESIGN: A prospective, randomized, nonblinded study. SETTING: University hospital. PARTICIPANTS: Forty patients undergoing elective primary coronary artery bypass graft, aortic valve replacement, or mitral valve replacement surgery. INTERVENTIONS: After a standardized anesthetic induction, anesthesia was maintained with a remifentanil infusion, 0.1 microg/kg/min, and desflurane, 3% to 10%, inspired (group I, n = 20) or a sufentanil infusion, 0.3 microg/kg/h, and desflurane, 3% to 10%, inspired (group II, n = 20). Patients receiving remifentanil were administered intrathecal morphine, 8 microg/ kg, for postoperative analgesia. MEASUREMENTS AND MAIN RESULTS: Both anesthetic regimens provided comparable intraoperative hemodynamic stability and similar recovery profiles, with extubation times of 5.1 +/- 4.3 hours (group I) and 5.8 +/- 6.7 hours (group II). CONCLUSIONS: Use of remifentanil in combination with intrathecal morphine did not facilitate earlier tracheal extubation or improve intraoperative hemodynamic stability compared with sufentanil alone for fast-track cardiac anesthesia.     

A comparison of two constant-dose continuous infusions of remifentanil for severe postoperative pain

We evaluated the analgesic efficacy and safety of two continuous constant-dose infusions of IV remifentanil, without infusion rate increments or the addition of boluses, in patients with severe postoperative pain during the first 4 h after general anesthesia with IV propofol-remifentanil. Thirty patients were randomly assigned to two groups of 15 subjects each according to the remifentanil dose administered: 0.1 microg. kg(-1). min(-1) IV (Group A) or 0.05 microg. kg(-1). min(-1) IV (Group B). Rescue analgesia was provided with meperidine (0.5 mg/kg IV) when pain intensity on the simple verbal scale (SVS) > or =2. The criteria for adequate analgesia (SVS 0-1, respiratory frequency >8/min. and SpO(2) >90%) after 4 h were met by 78% and 75% of the patients in Groups A and B, respectively (P = ns). "Meperidine rescue" analgesia was significantly more in Group B (26%) than in Group A (6%) (P < 0.05). There were no cases of respiratory depression, and nausea and emesis occurred in one patient in each group (6.5%). We conclude that IV remifentanil is an effective and safe opioid for the treatment of postoperative pain at a constant dose of 0.1 microg. kg(-1). min(-1) with a need for rescue analgesia 4 times less than a constant dose of 0.05 microg. kg(-1). min(-1). IMPLICATIONS: Our study suggests that the use of a constant continuous infusion of remifentanil 0.1 microg.kg(-1).min(-1)IV is an effective alternative in the treatment of severe postoperative pain.     

Dopexamine hydrochloride does not modify hemodynamic response or tissue oxygenation or gut permeability during abdominal aortic surgery

PURPOSE: To assess the effects of intraoperative infusion of dopexamine (a DA-1 and B2 adrenoreceptor agonist) on hemodynamic function, tissue oxygen delivery and consumption, splanchnic perfusion and gut permeability following aortic cross- clamp and release. METHODS: In a randomised double blind controlled trial 24 patients scheduled for elective infrarenal abdominal aortic aneurysm repair were studied in two centres and were assigned to one of two treatment groups. Group I received a dopexamine infusion starting at 0.5 microg x kg(-1) x min(-1) increased to 2 microg x kg(-1) x min(-1) maintaining a stable heart rate; Group II received a placebo infusion titrated in the same volumes following induction of anesthesia. Measured and derived hemodynamic data, tissue oxygen delivery and extraction and gut permeability were recorded at set time points throughout the procedure. RESULTS: Dopexamine infusion (0.5 -2 microg x kg x min(-1)) was associated with enhanced hemodynamic function (MAP 65 +/- 5.5 vs 92 +/- 5.7 mm Hg, P = <0.05) only during the period of aortic cross clamping. However, during the most part of infrarenal abdominal aortic surgery, dopexamine did not reduce systemic vascular resistance index, mean arterial pressure nor oxygen extraction compared with the control group. The lactulose/ rhamnose permeation ratio was elevated above normal in both groups (0.22 and 0.29 in groups I and II respectively). CONCLUSIONS: Dopexamine infusion (0.5 -2 microg x kg(-1) x min(-1)) did not enhance hemodynamic function and tissue oxygenation values during elective infrarenal abdominal aortic aneurysm repair.     

Total intravenous anesthesia with remifentanil, propofol and cisatracurium in end-stage renal failure

PURPOSE: To compare recovery parameters of total intravenous anesthesia (TIVA) with remifentanil and propofol, hemodynamic responses to perioperative events, and pharmacodynamic parameters of cisatracurium in 22 end-stage renal failure and 22 normal renal function patients. METHODS: Anesthesia was induced with 2-3 mg x kg(-1) propofol and 1 microg x kg(-1) remifentanil and maintained with 75 microg x kg(-1) x min(-1) propofol and propofol initial infusion of 0.2 microg x kg(-1) x min(-1) propofol. Arterial pressure and heart rate were maintained by remifentanil infusion rate adjustments. The first twitch (T1) was maintained at 25% by an infusion of cisatracurium. RESULTS: There was no difference in the time to maintenance of adequate respiration, date of birth recollection, first analgesic administration, between the renal failure (4.8+/-2.5, 7.8+/-3.2, 12.3+/-5.3 min respectively) and the control group (5.2+/-2.8, 8.1+/-3.1, 12.7+/-5.5 min): nor were there any differences in the time to 25% T1 recovery, T1 recovery from 25% to 75%, or cisatracurium infusion rate between the renal failure group (32.1 +/-10.8 min, 18.2+/-5.5 min, 0.89+/-0.29 microg x kg(-1) min(-1) respectively) and the control group (35.9 (7.9 min, 18.4+/-3.8 min, 0.95+/-0.22 microg x kg(-1) x min(-1)). CONCLUSION: End-stage renal failure does not prolong recovery from TIVA with remifentanil and propofol, or the recovery from cisatracurium neuromuscular block.     

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.     

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.     

Successful anesthetic management of three patients receiving pheochromocytoma resection using extremely high-dose remifentanil infusion

We describe three consecutive cases of successful anesthetic management for pheochromocytoma resection under balanced anesthesia with sevoflurane inhalation and extremely high-dose remifentanil infusion. This case series aimed to examine whether the aggressive dosing of remifentanil, exerting both depressor and bradycardic actions with short durations, is applicable for hemodynamic control during pheochromocytoma resection. The remifentanil infusion rate was set to maintain the systolic arterial pressure below 150 mmHg and heart rate below 100 beats x min(-1). In 2 of 3 cases, intraoperative hemodynamics were controlled by titrated remifentanil infusion with up to 2 and 3 microg x kg(-1) min(-1) in each case, without additional vasoactive agents. In another case, since adequate antihypertensive control was ineffective despite incremental remifentanil infusion to a maximum of 5 microg x kg(-1) x min(-1) supplemented with repeated boluses of 200 microg remifentanil, a total of 2.4 mg of nicardipine as a depressor was needed. Ephedrine 12 mg was employed following tumor removal. This anesthetic regimen thus allowed minimal or no concomitant use of depressors during tumor manipulation and vasopressors following tumor removal. In conclusion, the liberal use of remifentanil for the anesthetic management of pheochromocytoma resection appears to be simple, safe and effective.     

Narcotrend or bispectral index monitoring during desflurane-remifentanil anesthesia: a comparison with a standard practice protocol

Bispectral Index (BIS) (Aspect Medical Systems, Newton, MA) and Narcotrend (MonitorTechnik, Bad Bramstedt, Germany) are monitoring devices that were, as others, designed to assess the depth of anesthesia. Meanwhile, a number of studies indicate that with total IV anesthesia, BIS and Narcotrend have comparable effects on drug consumption and recovery times whereas comparative clinical data for volatile anesthetics are still missing. Therefore, we designed the present prospective, randomized, and double-blinded study to compare the effects of BIS and Narcotrend monitoring during desflurane-remifentanil anesthesia and versus a standard anesthetic practice protocol. One-hundred-twenty adult patients scheduled for minor orthopedic surgery were randomized to receive a desflurane-remifentanil anesthetic controlled either by Narcotrend or by BIS or solely by clinical variables. Anesthesia was induced with 0.4 microg x kg(-1) x min(-1) remifentanil and 2 mg/kg propofol. After tracheal intubation, remifentanil was infused at a constant rate of 0.2 microg x kg(-1) x min(-1) whereas desflurane in 1.5 L/min O(2)/air was adjusted according to clinical variables or the following target values: during maintenance of anesthesia to a value of "D(0)" (Narcotrend) or "50" (BIS), 15 min before the end of surgery to "C(1)" (Narcotrend) or "60" (BIS), whereas in the standard protocol group, desflurane was controlled according to clinical variables, e.g., heart rate, arterial blood pressure, movements. Recovery times and desflurane consumption were recorded by a blinded investigator. The desflurane vaporizer was weighed before and after anesthesia and consumption per minute was calculated. Data are mean +/- sd. The groups were comparable for demographic data, duration of anesthesia, and mean remifentanil dosages. Compared with standard practice, patients with Narcotrend or BIS monitoring needed significantly less desflurane (standard practice 443 +/- 71 mg/min, Narcotrend 374 +/- 124 mg/min, BIS monitoring 416 +/- 99 mg/min desflurane [both P < 0.05]). However, recovery times were not significantly different between the groups, e.g., opening of eyes 4.7 +/- 2.2 versus 3.7 +/- 2.0 versus 4.2 +/- 2.1 min. During desflurane-remifentanil anesthesia, Narcotrend and BIS monitoring seem to be equally effective compared with standard anesthetic practice: BIS and Narcotrend allow for a small reduction of desflurane consumption whereas recovery times are only slightly reduced. IMPLICATIONS: Monitoring the electroencephalogram with Narcotrend or Bispectral Index during desflurane-remifentanil anesthesia only slightly reduces recovery times when compared with a standard practice protocol.     

Fast-track cardiac anesthesia: use of remifentanil combined with intrathecal morphine as an alternative to sufentanil during desflurane anesthesia

The purpose of this cardiac fast-track study was to evaluate the use of remifentanil (R) combined with intrathecal (IT) morphine as an alternative to sufentanil (S) during desflurane anesthesia with respect to postoperative pain control. Prior to entering the operating room, patients in the R group (n = 20) received morphine, 8 microg/kg IT. Anesthesia was induced using a standardized anesthetic technique in all patients. In the R group, anesthesia was maintained with R, 0.1 microg. kg(-1). min(-1) in combination with desflurane 3-10%. In the S group (n = 20), patients received S 0.3 microg. kg(-1). h(-1) and desflurane 3-10%. There were no differences between the two groups with respect to time from arrival in the intensive care unit to tracheal extubation (5.1 +/- 4.3 h vs 5.8 +/- 6.7 h for R and S groups, respectively). After extubation, patients in the R group had significantly lower visual analog pain scores, reduced patient-controlled analgesic requirements, and greater satisfaction with their perioperative pain management, compared with patients in the S group. We conclude that R combined with IT morphine provided superior pain control after cardiac surgery compared with a S-based general anesthetic technique. Implications: As part of a cardiac fast-tracking program involving desflurane anesthesia, the use of intrathecal morphine in combination with a remifentanil infusion provided improved postoperative pain control, compared with IV sufentanil alone.     

Quality of emergence from anesthesia and incidence of vomiting with remifentanil in a pediatric population.

We conducted a randomized trial to compare the incidence of vomiting and the quality of emergence from anesthesia associated with the use of remifentanil versus a nonopiate. It was expected that remifentanil would provide smoother emergence from anesthesia with a comparably low rate of vomiting. The study sample consisted of 115 pediatric patients undergoing dental restoration and extraction who were randomly assigned to the nonopiate or remifentanil groups based on their hospital admission numbers. The nonopiate patients received sufficient desflurane to prevent movement, typically 7%-9%. The remifentanil group received remifentanil 0.2 microg x kg(-1) x min(-1) and enough desflurane to prevent movement, typically 3.2%-3.6%. A trained postanesthesia care unit nurse, blinded to the anesthetic technique, assessed the quality of emergence and incidence of vomiting. Sixty-three patients received remifentanil and 52 received the nonopiate. The groups were not significantly different in either quality of emergence or incidence of vomiting. Remifentanil provided results comparable to a nonopiate with no increase in emesis. IMPLICATIONS: A randomized, controlled clinical trial of 115 patients undergoing dental restoration indicated that an anesthetic technique using remifentanil provided quality of emergence comparable to and no greater incidence of vomiting than a nonopiate technique.     

Low doses of rocuronium during remifentanil-propofol-based anesthesia in children: comparison of intubating conditions

BACKGROUND : In this prospective double-blind study, intubation conditions were compared at 90 s following two different low doses of rocuronium during remifentanil and propofol anesthesia in children undergoing ambulatory procedures. METHODS : Forty-four children (ASA I-II, aged 3-12 years) undergoing day case ENT surgery were premedicated with midazolam 0.5 mg x kg(-1). Following atropine 10 microg x kg(-1), remifentanil infusion 0.5 microg x kg(-1) x min(-1) was started. After 60 s, anesthesia was induced with propofol 2.5 mg x kg(-1). Immediately after a bolus dose of propofol, the children received rocuronium doses of 0.15 mg x kg(-1) (group I, n = 22) or 0.3 mg x kg(-1) (group II, n = 22) in a randomized manner, after which an infusion of propofol 6 mg x kg(-1) h(-1) was added to the infusion of remifentanil 0.5 microg x kg(-1) min(-1) for maintenance of anesthesia. Intubating conditions were evaluated 90 s after rocuronium administration applying the Copenhagen Scoring System which included components of laryngoscopy, vocal cord movement and reaction to intubation. Hemodynamic values were recorded at predetermined time intervals. RESULTS : Excellent, good and poor intubation conditions were 18.2, 40.9 and 40.9% in group I and 40.9, 54.5 and 4.5% in group II. Clinically acceptable intubating conditions (excellent and good) were significantly higher in group II (95.5%) than in group I (59.1%) (P = 0.004). Mean values of heart rate and blood pressure did not differ significantly between groups. No children required any intervention for hemodynamic instability and/or muscle rigidity. CONCLUSIONS : The results suggest that 0.3 mg x kg(-1) of rocuronium may be a better low dose than 0.15 mg x kg(-1) of rocuronium for clinically acceptable intubating conditions in pediatric ambulatory surgery during remifentanil-propofol-based anesthesia at the doses used in the study.