A comparison of anaesthesia using remifentanil combined with either isoflurane, enflurane or propofol in patients undergoing gynaecological laparoscopy, varicose vein or arthroscopic surgery

BACKGROUND: Anaesthesia comprising remifentanil plus isoflurane, enflurane or propofol was randomly evaluated in 285, 285 and 284 patients, respectively, undergoing short-procedure surgery. METHODS: Anaesthesia was induced with propofol (0.5 mg x kg(-1) and 10 mg x 10 s(-1)), and a remifentanil bolus (1 microg x kg(-1)) and infusion at 0.5 microg x g(-1) x min(-1). Five minutes after intubation, remifentanil infusion was halved and 0.5 MAC of isoflurane or enflurane, or propofol at 100 microg x kg(-1) x min(-1) were started and titrated for maintenance. RESULTS: Patient demography and anaesthesia duration were similar between the groups. Surgery was performed as daycases (52%) or inpatients (48%). The median times (5-7 min) to extubation and postoperative recovery were similar between the groups. Responses to tracheal intubation (15% vs 8%) and skin incision (13% vs 7%) were significantly greater in the total intravenous anaesthesia (TIVA) group (P<0.05). Fewer patients given remifentanil and isoflurane (21%) or enflurane (19%) experienced > or =1 intraoperative stress response compared to the TIVA group (28%) (P<0.05). Median times to qualification for and actual recovery room discharge were 0.5-0.6 h and 1.1-1.2 h, respectively. The most common remifentanil-related symptoms were muscle rigidity (6-7%) at induction, hypotension (3-5%) and bradycardia (1-4%) intraoperatively and, shivering (6-7%), nausea and vomiting postoperatively. Nausea (7%) and vomiting (3%) were significantly lower with TIVA compared with inhaled anaesthetic groups (14-15% and 6-8%, respectively; P<0.05). CONCLUSION: Anaesthesia combining remifentanil with volatile hypnotics or TIVA with propofol was effective and well tolerated. Times of extubation, postanaesthesia recovery and recovery room discharge were rapid, consistent and similar for all three regimens.     

Use of a remifentanil-propofol mixture for pediatric flexible fiberoptic bronchoscopy sedation

BACKGROUND: Flexible fiberoptic bronchoscopy is an important diagnostic tool for pediatric pulmonologists. Because of its favorable respiratory profile, ketamine has become a popular sedative for this procedure, but may be associated with unpleasant emergence reactions in the older child. Remifentanil is a newer, ultra-short acting opioid that has been shown to provide effective sedation and cough suppression for fiberoptic bronchoscopy when combined with intermittent propofol boluses. However, delivery of these agents as a combined, single infusion has not been described. METHODS: Children > or =2 years of age undergoing fiberoptic bronchoscopy were enrolled. Remifentanil was mixed in a single syringe with undiluted propofol giving final drug concentrations of 10 mg x ml(-1) of propofol and 15-20 microg x ml(-1) of remifentanil. Sedation was induced with a bolus of approximately 0.1 ml x kg(-1) of this mixture and maintained by titrating the drip throughout the procedure. Vital signs, sedative effectiveness, recovery patterns, and complications were prospectively recorded. RESULTS: Fifteen patients aged 9.0 +/- 5.3 years were sedated. Sedation was induced with 1.2 +/- 0.4 mg x kg(-1) propofol (2.4 +/- 0.8 microg x kg(-1) remifentanil) and maintained with 4.1 +/- 1.8 mg x kg(-1) x h(-1) propofol (0.13 +/- 0.06 microg x kg(-1) x min(-1) remifentanil). Five patients received low-dose ketamine to augment sedation. The maximal decrease in respiratory rate was 6.1 +/- 5.3 b x min(-1) (27.6 +/- 21%) and no patient became hypoxemic. All procedures were completed easily without significant complication. Patients recovered to baseline 13.3 +/- 8.5 min following infusion discontinuation. CONCLUSIONS: A remifentanil/propofol mixture provided effective sedation and rapid recovery in pediatric patients undergoing fiberoptic bronchoscopy.     

Assessment of depth of anesthesia and postoperative respiratory recovery after remifentanil- versus alfentanil-based total intravenous anesthesia in patients undergoing ear-nose-throat surgery

BACKGROUND: The authors investigated whether total intravenous anesthesia (TIVA) with precalculated equipotent infusion schemes for remifentanil and alfentanil would ensure appropriate analgesia and that remifentanil would result in better recovery characteristics. METHODS: Forty consenting patients (classified as American Society of Anesthesiologists physical status I-III) scheduled for microlaryngoscopy were randomized to receive, in a double-blind manner, either remifentanil (loading dose 1 microg/kg; maintenance infusion, 0.25 microg x kg(-1) x min-1) or alfentanil (loading dose, 50 microg/kg; maintenance infusion, 1 microg x kg(-1) x min-1) as the analgesic component of TIVA. They were combined with propofol (loading dose, 2 mg/kg; maintenance infusion, 100 microg x kg(-1) min(-1)). To insure an equal state of anesthesia, the opioids were titrated to maintain heart rate and mean arterial pressure within 20% of baseline, and propofol was titrated to keep the bispectral index (BIS) less than 60. Neuromuscular blockade was achieved with succinylcholine. Drug dosages and the times from cessation of anesthesia to extubation, verbal response, recovery of ventilation, and neuropsychological testing, orientation, and discharge readiness were recorded. RESULTS: Demographics, duration of surgery, and anesthesia were similar between the two groups. Both groups received similar propofol doses. There were no difference in BIS values preoperatively (mean, 96), intraoperatively (mean, 55), and postoperatively (mean, 96). Recovery of BIS and times for verbal response did not differ. At 20, 30, and 40 min after terminating the opioid infusion, the peripheral oxygen saturation and respiratory rate were significantly higher in the remifentanil group compared with the alfentanil group. CONCLUSIONS: When both the hypnotic and analgesic components of a TIVA-based anesthetic are administered in equipotent doses, remifentanil provides a more rapid respiratory recovery, even after brief surgical procedures, compared with alfentanil.     

Remifentanil vs alfentanil in the total intravenous anaesthesia for paediatric abdominal surgery

BACKGROUNDS: Our aim was to investigate whether total intravenous anaesthesia (TIVA) with remifentanil and alfentanil would ensure appropriate analgesia and recovery conditions in anaesthesia for children undergoing abdominal surgery. METHODS: Sixty children, scheduled for abdominal operations were randomized to receive, in a double-blind manner, either remifentanil (loading dose 1 microg x kg(-1); maintenance infusion, 0.25 microg x kg(-1) min(-1)) or alfentanil (loading dose 50 microg x kg(-1); maintenance infusion, 1 microg x kg(-1) min(-1)) as the analgesic component of TIVA. They were combined with propofol (loading dose, 2 mg x kg(-1); step 1 maintenance infusion, 10 mg x kg(-1) h(-1); step 2 maintenance infusion, 8 mg x kg(-1) h(-1); step 3 maintenance infusion, 6 mg x kg(-1) h(-1)) neuromuscular blockade was with mivacurium. Dose changes of the drugs, the times from cessation of anaesthesia to extubation, verbal responses, recovery of ventilation, orientation, and qualification for discharge from the postanaesthetic care unit (PACU) were recorded. RESULTS: Demographics, duration of surgery and anaesthesia were similar between the two groups. Times to extubation and stay in the PACU were significantly shorter in the remifentanil group compared with the alfentanil group. Quality of emergence (QE) from anaesthesia scale scores were higher in the remifentanil group compared with the alfentanil group. CONCLUSIONS: Remifentanil provides a more rapid recovery and adequate postoperative analgesia after TIVA for paediatric abdominal surgery, compared with alfentanil.     

Total intravenous anesthesia with remifentanil and propofol for implantation of cardioverter-defibrillators in patients with severely reduced left ventricular function

OBJECTIVE: To determine the cardiocirculatory effects of total intravenous anesthesia (TIVA) using remifentanil and propofol in high-risk cardiac surgical patients. DESIGN: Prospective study of 20 patients undergoing first-time implantation of a cardioverter-defibrillator (ICD). SETTING: Major, community, university-affiliated hospital. PARTICIPANTS AND INTERVENTIONS: In 20 patients with severely reduced left ventricular function (left ventricular ejection fraction <30%) undergoing first-time implantation of an ICD, TIVA using remifentanil and propofol was performed. MEASUREMENTS AND MAIN RESULTS: Extensive hemodynamic monitoring using a pulmonary artery catheter was performed: (T1) before induction of anesthesia, (T2) after intubation, (T3) after skin incision, (T4) after first defibrillation, and (T5) 10 minutes after extubation. Propofol, 3.0 +/- 0.6 mg/kg/h (range, 1.9 to 4.4 mg/kg/h), and remifentanil, 0.30 +/- 0.05 microg/kg/min (range, 0.21 to 0.40 microg/kg/min), were used. Total costs added up to US $44.60 per patient. Patients could be extubated within 12.5 +/- 4.2 minutes after stopping anesthesia. There were significant decreases in heart rate (HR; from 77 +/- 12 to 57 +/- 10 beats/min [T3]), mean arterial blood pressure (MAP; from 98 +/- 14 to 70 +/- 12 mmHg [T2]), and systemic vascular resistance (from 1,551 +/- 309 to 1,233 +/- 274 dyne x s x cm(-5) [T2]). Cardiac index (CI) slightly decreased only at T3 (from 2.46 +/- 0.42 to 1.92 +/- 0.29 L/min/m2; p = 0.04). The decrease in MAP could easily be treated by volume infusion in most patients (17 patients). Sixty-five percent of the patients needed dobutamine to increase CI to greater than 2.0 L/min/m2 (mean dose, 2.2 +/- 1.8 microg/kg/min). Dobutamine could be stopped before extubation in all patients. No patient needed sustained inotropic or ventilatory support and intensive care therapy could be avoided. CONCLUSION: TIVA using remifentanil and propofol in patients with severely reduced left ventricular function is safe, well-controllable, and allows early extubation after implantation of an ICD. Because patients without complications did not need a postoperative intensive care stay, costs may be considerably reduced.     

Comparison of total intravenous anesthesia and sevoflurane-fentanyl anesthesia for outpatient otorhinolaryngeal surgery

STUDY OBJECTIVE: To compare the recovery characteristics of two widely used anesthetic techniques: remifentanyl-propofol and sevoflurane-fentanyl in a standardized ambulatory population.DESIGN: Randomized, single-blinded study. SETTING: University-affiliated medical center. PATIENTS: 50 ASA physical status I and II patients undergoing elective ambulatory otorhinolaryngeal surgery. INTERVENTIONS: Patients were randomized two groups to receive total intravenous anesthesia (TIVA group) with remifentanil and propofol or sevoflurane-fentanyl (SF group). TIVA patients received induction with propofol 1.5 mg/kg intravenously (IV) and remifentanil 0.5 microg/kg IV. The anesthesia was continued with a continuous infusion of propofol 100 microg/kg/min and remifentanil 0.0625-0.25 microg/kg/min. The SF group received, at induction, fentanyl 2 microg/kg followed by propofol 1.5 mg/kg IV. Maintenance was obtained with 1 to 1.5 minimum alveolar concentration of sevoflurane and bolus of fentanyl 1 microg/kg IV as needed. MEASUREMENTS AND MAIN RESULTS: Early recovery times (eye opening, response to commands, extubation, orientation, operating room stay after surgery, and Aldrete score > or =9) and patient satisfaction were similar between the two groups. Postanesthetic discharge scoring system (PADSS) > or = 9 was significantly shorter for the TIVA group (135.9 +/- 51 vs. 103 +/- 32 min) (p < 0.01) but this difference was not associated with a shorter postanesthesia care unit (PACU) length of stay. CONCLUSION: Early recovery times are comparable between total intravenous anesthesia and sevoflurane-based anesthesia. Even though patients in the TIVA group achieved home readiness criteria in a significantly shorter time, this technique does not shorten PACU length of stay, which depends instead on multiple nonmedical and administrative issues.     

Bispectral index-guided administration of anaesthesia: comparison between remifentanil/propofol and remifentanil/isoflurane

BACKGROUND AND OBJECTIVE: The bispectral index of the electroencephalogram is a measure of the hypnotic component of anaesthesia and can be used to guide the administration of anaesthesia. This study compares bispectral index-guided anaesthesia with remifentanil and either propofol or isoflurane. METHODS: Eighty consenting patients were randomly assigned to two groups. Following induction with propofol and remifentanil, anaesthesia was maintained with remifentanil/propofol or remifentanil/isoflurane. Remifentanil infusion rates were guided by haemodynamic responses--maintaining mean arterial pressure and heart rate within 20% of baseline. Propofol and isoflurane administration was guided using the bispectral index (45-60). Thirty minutes before the end of surgery, morphine was administered (0.15 mg kg(-1) intravenously). Fifteen minutes before end of surgery, propofol and isoflurane were reduced (bispectral index 60-75). At the end of surgery, the anaesthetic agents were discontinued. Groups were compared for recovery, remifentanil doses and signs of inadequate anaesthesia using the chi2-test and ANOVA (P < 0.05). RESULTS: The duration of surgery was longer in the propofol/remifentanil group (121 +/- 53 versus 94 +/- 40 min). Recovery data were not different between groups. The remifentanil infusion rate was significantly lower with additional isoflurane (0.18 +/- 0.06 microg kg(-1) min(-1)) than with additional propofol (0.31 +/- 0.20 microg kg(-1) min(-1)). The propofol infusion rate was 123 +/- 48 microg kg(-1) min(-1); isoflurane concentration was 0.66 +/- 0.13%. CONCLUSIONS: Bispectral index-guided anaesthesia with remifentanil plus propofol or isoflurane results in the absence of postoperative recall and a fast recovery with both drug combinations. In our patients, at comparable bispectral index-levels, haemodynamic control requires higher doses of remifentanil with propofol than with isoflurane.     

Desflurane reduces the effective therapeutic infusion rate (ETI) of cisatracurium more than isoflurane, sevoflurane, or propofol

PURPOSE: The present study investigated the interaction between the cumulative dose requirements of cisatracurium and anesthesia with isoflurane, sevoflurane, desflurane or propofol using closed-loop feedback control. METHODS: Fifty-six patients (18-85 yr, vitrectomies of more than one hour) were studied. In the volatile anesthetics groups, anesthesia was maintained by 1.3 MAC of isoflurane, sevoflurane or desflurane; in the propofol group, anesthesia was maintained by a continuous infusion of 6-8 mg.kg(-1).hr(-1) propofol. After bolus application of 0.1 mg.kg(-1) cisatracurium, a T1%-level of 10% of control level (train-of-four stimulation every 20 sec) was maintained using closed-loop feedback controlled infusion of cisatracurium. The effective therapeutic infusion rate (ETI) was estimated from the asymptotic steady-state infusion rate Iss. The Iss was derived from fitting an asymptotic line to the measured cumulative dose requirement curve. The ETI of the different groups was compared using Kruskal-Wallis- test, followed by rank sum test, corrected for the number of comparisons, P <0.05 was regarded as showing significant difference. RESULTS: ETI in the isoflurane group was 35.6 +/- 8.6 microg.m(-2).min(-1), in the sevoflurane group 36.4+/- 11.9 microg m(-2).min(-1), in the desflurane group 23.8 +/- 6.3 microg.m(-2).min(-1). The ETI of the volatile anesthetic groups were all significantly lower than the ETI in the propofol group at 61.7 +/- 25.3 microg.m(-2).min(-1) (P <0.002). The ETI in the desflurane group was significantly lower than in all other groups (P <0.02). CONCLUSION: In comparison to propofol, isoflurane, sevoflurane and desflurane reduce the cumulative dose requirements of cisatracurium to maintain a 90% neuromuscular blockade by 42%, 41% and 60%, respectively.     

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.     

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 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.     

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.     

Total intravenous anesthesia with propofol augments the potency of mivacurium

BACKGROUND: Little is known about the potentiating effect of propofol on neuromuscular blocking drugs. However, some animal studies indicate a dose-dependent increase of the potency of neuromuscular blocking drugs by propofol. This study compared mivacurium potency after five minutes and after 20 min of total intravenous anesthesia with propofol (TIVA propofol). METHODS: Twenty-eight patients were randomized into two groups, after approval of the Ethics Committee and written consent. Anesthesia was induced, in all patients, using remifentanil 0.5 microg.kg(-1).min(-1) for two minutes, after which: 3 mg.kg(-1) of propofol was injected; a laryngeal mask airway was inserted; and intermittent, positive pressure ventilation was initiated. Anesthesia was maintained using TIVA propofol (titrated using bispectral index monitoring to 40-45). Neuromuscular monitoring consisted of phonomyography at the adductor pollicis muscle. In Groups 5 min and 20 min, a tetanic stimulation of the ulnar nerve commenced after four minutes and after 19 min of TIVA, respectively, followed by controlled, single twitch stimulation at 1 Hz for one minute. Boli of 60, 30, 30, and 30 microg.kg(-1) mivacurium, respectively, were administered (each drug increment was administered after the effect of the previous dose had caused a stable response), and single twitch stimulation continued at 0.1 Hz. The dose-response curve was determined for both groups; potency was calculated using log-probit analysis. Data were presented as mean (SD) and were compared using two-sided analysis of variance, P < 0.05. RESULTS: Patient characteristics were similar in the two groups. The corresponding ED(50) and ED(95) values were greater, at 76.7 +/- 12.4 microg.kg(-1) and 146.6 +/- 27.6 microg.kg(-1) for Group 5 min, vs 46.7 +/- 12.2 microg.kg(-1) and 101.1 +/- 20.2 microg.kg(-1) for Group 20 min, respectively. CONCLUSIONS: After 20 min of TIVA propofol, the potency of mivacurium is approximately 50% greater than after five minutes of TIVA propofol. For clinical purposes, it is important, therefore, to consider the duration of TIVA propofol before determining the dose of neuromuscular blocking drug.     

Propofol and remifentanil for deep sedation in children undergoing gastrointestinal endoscopy

PURPOSE: The aim of this study was to evaluate the safety and efficacy of a combination of propofol and remifentanil deep sedation in spontaneously breathing children less than 7 years of age undergoing upper and/or lower gastrointestinal endoscopy. METHODS: The effect of propofol and remifentanil sedation was prospectively studied in 42 unpremedicated children undergoing gastrointestinal endoscopy. Anesthesia was induced with a combination of sevoflurane, nitrous oxide and oxygen. Anesthesia was maintained with an infusion of propofol (50-80 microg x kg(-1) x min(-1)) and remifentanil (0.1 microg x kg(-1) x min(-1)). Demographic data, heart rate, blood pressure, respiratory rate, and oxygen saturation were recorded every 5 min for each child. In addition, recovery and discharge times were recorded. RESULTS: All 42 procedures were completed with no complications. The combination of propofol and remifentanil resulted in a decrease in heart rate, blood pressure, and respiratory rate. There was no respiratory depression or oxygen desaturation in any child. A bolus of propofol (1 mg x kg(-1)) was necessary in one child for excessive movement. No patient experienced any side effects in the recovery period. CONCLUSION: The combination of propofol and remifentanil for sedation in children undergoing gastrointestinal endoscopy can be considered safe, effective and acceptable.     

Analgesic transition after remifentanil-based anesthesia in neurosurgery. A comparison of sufentanil and tramadol

AIM: Transition from the end of remifentanil infusion and postoperative analgesia must be planned carefully owing to remifentanil's (R) rapid offset. Intraoperative morphine has been used for the transition to postoperative analgesia following remifentanil-based anesthesia. Sufentanil (S) is a very potent opioid with high micro-receptor affinity, a much wider therapeutic index and a lower fractional receptor occupancy. These pharmacological and dynamics features make sufentanil an interesting alternative to morphine for immediate postoperative analgesia. METHODS: Experimental design: perspective, randomized, single blinded and comparative study. Institution: neurosurgical operating theatre at University. Patients: 96 patients, aging from 25 to 67 years, ASA class I-III, undergoing neurosurgical operations, were studied. Interventions and Measurements: the anesthetic management was: premedication: atropine 0.01 microg kg(-1) + remifentanil 0.20 microg kg(-1) min(-1); induction: propofol 2.0 microg kg(-1) + cisatracurium 0.15 microg kg(-1); maintenance: sevoflurane 0.8% + remifentanil (titrated infusion) cisatracurium. All patients received ketorolac 30 mg i.v. 1 hour before the end of surgery and ketorolac (60-90 mg) + tramadol (200-300 mg) by elastomeric pump; patients were divided into 2 groups: group T receiving tramadol 100 mg and group S receiving a bolus dose of sufentanil 0.10 microg kg(-1), 30 and 15 minutes before the end of surgery respectively. Recovery time, postoperative analgesia evaluated by VAS, cardiocirculatory parameters and side effects like nausea, vomiting, shivering, muscle rigidity, sedation and respiratory depression were recorded. RESULTS: VAS was significantly lower in Group S. Recovery time was shorter in Group T than in Group S (8.8 +/- 3.6 vs 11.6 +/- 4.6 min), no statistically significant differences between groups as regards nausea, vomiting and shivering. Short-lasting respiratory depression was detected in 3 cases in Group S. CONCLUSION: At the emergence much better control of the transition phase in patients treated with sufentanil: smooth recovery with better tolerability of the endotracheal tube; efficacious analgesia along with cardiocirculatory stability.     

Remifentanil and controlled hypotension; comparison with nitroprusside or esmolol during tympanoplasty

PURPOSE: To determine whether remifentanil, combined with propofol, could induce controlled hypotension, reduce middle ear blood flow (MEBF) measured by laser-Doppler flowmetry, provide a "dry" operative field, and could be compared with nitroprusside or esmolol combined with alfentanil and propofol. METHODS: Thirty patients undergoing tympanoplasty and anesthetized with 2.5 mg x kg(-1) propofol iv followed by a constant infusion of 120 microg x kg(-1) x min(-1), were randomly assigned in three groups to receive either 1 microg x kg(-1) remifentanil iv followed by a continuous infusion of 0.25 to 0.50 microg x kg(-1) x min(-1), or nitroprusside iv, or esmolol iv combined for the latter two groups with alfentanil iv. RESULTS: Controlled hypotension was achieved at the target pressure of 80 mmHg within 107 +/- 16, 69 +/- 4.4, 53.3 +/- 4.4 sec for remifentanil, nitroprusside and esmolol respectively. MEBF decreased by 24 +/- 0.3, 22 +/- 3.3, 37 +/- 3% and preceded the decrease in SABP, within 30 +/- 6.1, 11.2 +/- 3.1, 15 +/- 2.8 sec for remifentanil, nitroprusside and esmolol respectively. Remifentanil, and nitroprusside decreased MEBF autoregulation less than esmolol (0.36 +/- 0.1, 0.19 +/- 0.2, -0.5 +/- 0.2). Controlled hypotension was sustained in all three groups throughout surgery, and the surgical field rating decreased in a range of 80% in all three groups. Nitroprusside decreased pH and increased PaCO2. There were no postoperative complications in any of the groups. CONCLUSIONS: Remifentanil combined with propofol enabled controlled hypotension, reduced middle ear blood flow and provided good surgical conditions for tympanoplasty with no need for additional use of a potent hypotensive agent.     

Recovery of neuromuscular block after continuous infusion of cisatracurium in patients with renal dysfunction]

OBJECTIVE: Study of the recovery of neuromuscular block after continuous infusion of cisatracurium in patients with renal dysfunction. STUDY DESIGN: Prospective case-control study. PATIENTS: Forty adult patients scheduled for urological surgery were assigned to two groups according to the creatinine clearance (CC) as a measure of the renal function: group IR (CC < 60 mL.min-1) or group NR (CC > or = 60 mL.min-1). METHODS: After premedication with hydroxyzine, anaesthesia was induced with propofol, sufentanil and cisatracurium (0.15 mg.kg-1), and maintained using isoflurane, sufentanil and a continuous infusion of cisatracurium (0.12 mg.kg-1.h-1) adjusted for maintained a post-tetanic count < or = 5. Neuromuscular transmission was monitored at the adductor pollicis using accelerography (TOF Gard). Onset and recovery times in both groups were compared using Student's t test. RESULTS: Infusion time and total dose of cisatracurium were comparable in both groups. Onset times were 3.9 +/- 0.8 min and 3.5 +/- 0.6 min in groups IR and NR respectively. After the infusion, the time to train-of-four ratio of 0.8 were not different in both groups: 77 +/- 18 min (group IR) and 73 +/- 13 min (group NR). However, the spontaneous recovery intervals 25%-75% were delayed in group IR (20 +/- 9 min vs 14 +/- 5 min p < 0.05). CONCLUSION: There are minor differences in the pharmacodynamics of cisatracurium between patients with normal or impaired renal function. Nevertheless, a marked interindividual variability in the recovery parameters was observed in patients with renal dysfunction.     

A comparison of remifentanil and alfentanil for use with propofol in patients undergoing minimally invasive coronary artery bypass surgery

Most patients undergoing minimally invasive direct coronary artery bypass surgery can be awakened and tracheally extubated in the operating room. We have compared two techniques of total IV anesthesia in this patient population: 30 patients (aged 44 to 74 yr; 24 male) premedicated with temazepam were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 2 microg/kg or with alfentanil 40 microg/kg, with propofol, and maintained with remifentanil at 0.25 or 0.5 microg x kg(-1) x min(-1) or alfentanil at 0.5 or 1 microg x kg(-1) x min(-1). The stable maintenance infusion rate of propofol was adjusted for age. Times to awakening and tracheal extubation were recorded. Postoperatively, IV morphine provided by patient-controlled analgesia was used for 48 h. Times to awakening and tracheal extubation (mean +/- SD) were shorter (P < 0. 01) in patients receiving remifentanil, and interpatient variations in times to awakening and tracheal extubation smaller (awakening 25 +/- 7 vs 74 +/- 32 min, and extubation 27 +/- 7 vs 77 +/- 32 min). Analysis of variance revealed that postoperative consumption of morphine was dependent on both the intraoperative opioid and the time elapsed after surgery (P < 0.05): patient-controlled analgesia morphine use during the first 3 h after awakening was more in patients receiving remifentanil (P < 0.01). Implications: Recovery of patients undergoing Minimally Invasive Direct Coronary Artery Bypass Surgery is significantly shorter and more predictable after total IV anesthesia with remifentanil-propofol than with alfentanil-propofol, which may be important if the goal is that patients will be awakened and tracheally extubated in the operating room.     

The effect of anesthetic technique on recovery from neuromuscular blockade with cisatracurium

OBJECTIVES: To assess the effect of four anesthetic techniques on recovery after a single dose of 0.2 mg/kg of cisatracurium. PATIENTS AND METHOD: After giving informed consent, 96 patients of both sexes, ASA I-III, were enrolled. Anesthesia was induced with fentanyl, propofol O2-N2O (FiO2 40%) after which the patients were randomly assigned to four groups according to maintenance technique: propofol by infusion, sevoflurane, desflurane or isoflurane at 1.3 MAC. Neuromuscular block was monitored (electromyographic recording of the pollicis adductor). Variables recorded were time of maximum block, duration of action of 1% and 25%, and recovery indices at T0-TR75 andT25%-T75%. ANOVA was performed ( = 0.05 and beta = 0.1). RESULTS: The groups were homogeneous. Time until recovery of 25% of baseline amplitude of the first response to a train of four (TOF) (T1) was longer in the desflurane group (68.4 +/- 11.1 min) than in the propofol group (60.2 +/- 9.4 min; p < 0.05). Time until recovery of 75% of the TOF-ratio was longer in the sevoflurane (96.8 +/- 13.1 min), desflurane (101.5 +/- 14.4 min) and isoflurane (94.1 +/- 13.9 min) groups than in the propofol group (83.7 +/- 1.3 min) (p < 0.0001).Times until recovery of T1 up to 1% were not statistically different: 45.8 +/- 10.7 (propofol), 50.6 +/- 11.0 (sevoflurane), 51.3 +/- 11.5 (desflurane) and 46.5 +/- 11.2 min (isoflurane). The 25% - 75% recovery index was also similar at 19.0 +/- 9.3 (propofol), 20.0 +/- 5.1 (sevoflurane), 25.7 +/- 12.4 (desflurane) and 20.9 +/- 7.9 (isoflurane). CONCLUSIONS: The inhaled anesthetics studied prolong the duration of clinical effect of cisatracurium more than does propofol.