Total intravenous versus inhalational anaesthesia for colonoscopy: a prospective study of clinical recovery and psychomotor function

A randomized, prospective study was conducted on 69 patients comparing recovery after two different anaesthetic techniques for ambulatory colonoscopy. Thirty-five patients received an intravenous fentanyl (1 microg/kg), midazolam (0.05 to 0. 075 mg/kg) and propofol (10 to 20 mg boluses as required) combination. 34 patients received sevoflurane in 67% nitrous oxide. Drug administration was titrated to clinical signs. At baseline and 30, 60, 90 and 120 minutes after the procedure patient performance on a comprehensive battery of psychomotor tests was recorded. Emergence times were noted. Depth of sedation was assessed at 5 minute intervals for 30 minutes after the end of the procedure. Emergence times were faster in the fentanyl/midazolam/propofol group by 2.2 minutes. A lower sedation score was detected at 20 minutes in the sevoflurane/nitrous oxide group. Psychomotor impairment was of a greater magnitude and more prolonged by 30 to 90 minutes in the fentanyl/midazolam/propofol group. It is concluded that a sevoflurane/nitrous oxide anaesthetic has a suitable recovery profile for ambulatory colonoscopy and results in faster recovery of cognitive function compared with a fentanyl, midazolam and propofol combination.

[Selection and effects of sedation in intensive care]

The importance of sedation in the ICU. The authors shortly describe the use of sedation as useful tool to reduce patient discomfort and to modulate stress response, in critically ill patients.

Small-dose selective spinal anaesthesia for short-duration outpatient gynaecological laparoscopy: recovery characteristics compared with propofol anaesthesia

A randomized controlled trial compared recovery characteristics after selective spinal anaesthesia (SSA) or propofol general anaesthesia (GA) for short-duration outpatient laparoscopic surgery. Forty women were randomized to receive either SSA (1% lidocaine 10 mg, sufentanil 10 microg and sterile water 1.8 ml) or GA (propofol and nitrous oxide 50% in oxygen). Compared with the GA group, times to leaving the operating room, performing a straight leg raise, performing deep knee-bends and achieving an Aldrete score >9 and the time in Phase II recovery were significantly shorter (P < 0.05) in the SSA group.

Effects of ephedrine on the onset time of neuromuscular block and intubating conditions after cisatracurium: preliminary results

We studied the effects of intravenous ephedrine on the onset time and the intubating conditions 2 min after a bolus dose of cisatracurium (0.15 mg kg-1). Thirty patients anaesthetized with sufentanil and propofol were randomly divided in 2 groups to receive either ephedrine (70 micrograms.kg-1) or saline, 5 s before propofol. Cisatracurium was administered after loss of consciousness. Neuromuscular block was assessed at the adductor pollicis using accelography. Tracheal intubation was performed 2 min after cisatracurium injection and rated as excellent, good, poor or bad. At intubation, neuromuscular block (% height of control T1) was greater in patients receiving ephedrine (36.1 +/- 25.8% vs 57.9 +/- 25.1%) (mean +/- SD). The frequency of excellent intubating conditions was higher after ephedrine (86.6%) than after saline (40.0%). The onset time of cisatracurium was shorter after ephedrine (167 +/- 64.8 s vs 234.9 +/- 63.1 s). Thus, a low dose of ephedrine given before induction of anaesthesia improves the intubating conditions 2 min after 0.15 mg kg-1 cisatracurium and this effect likely relates to a quicker onset of neuromuscular block.

Haemodynamic comparison of propofol-fentanyl anaesthesia with midazolam-fentanyl anaesthesia in CABG patients without preoperative heart failure

This study was designed to compare prebypass haemodynamics under total intravenous anaesthesia (TIVA) using midazolam-fentanyl (group M) and propofol-fentanyl (group P) combinations. Sixteen adult patients undergoing CABG were studied with patients in group M and P (n = 8 each) given intravenous midazolam 0.1 mg.kg-1.h-1 and propofol 4 mg.kg-1.h-1 with fentanyl 25 micrograms.kg-1 until sternotomy, respectively. Following induction of anaesthesia, cardiac index and heart rate decreased significantly (30% and 20% in both groups, p < 0.05) these variables returned to baseline on completion of sternotomy. In addition, in group P mean arterial pressure decreased significantly (about 15%) following induction and there were no ischaemic signs. Overall for MAP there was no significant difference between the two groups. LVSWI and RVSWI were reduced by around 25% in both groups. Only the change in LVSWI reached statistical significance (p < 0.05). This reduction may have exert a caridioprotectant action by decreasing myocardial oxygen consumption. We conclude that both TIVA techniques represent an acceptable anaesthetic regimen for use in cardiac anaesthesia.

Premedication modifies the quality of sedation with propofol during regional anesthesia

PURPOSE

To determine the effects of diazepam or clonidine on the quality of sedation with propofol during regional anesthesia.

METHODS

In a prospective randomised, controlled, double-blinded study, 60 patients undergoing elective gynecological surgery were studied. They were given premedication with 0.15-mg clonidine (Group-CL, n=20), 5-mg diazepam (Group-DZ, n = 20), or placebo (Group-P, n = 20) po. After spinal anesthesia was established, sedation was provided with propofol and controlled using a five-point sedation score at 3, "eyes closed but rousable to command", and 4, "eyes closed but rousable to mild physical stimulation". During sedation, blinded anesthesiologist recorded occurrence of complications. At two hours after end of sedation, patients were asked if they had intraoperative dream and memory.

RESULTS

The loading dose, steady-state infusion rate, and overall mean infusion rate in Group-CL were 0.80 mg x kg(-1), 2.35 mg x kg(-1) x hr(-1) and 2.89 mg x kg(-1) x hr(-1), compared with 0.97 mg x kg(-1), 3.13 mg x kg(-1) x hr(-1) and 3.59 mg x kg(-1) x hr(-1) in Group-DZ, and 1.38 mg x kg(-1), 4.10 mg x kg(-1) x hr(-1) and 4.36 mg x kg(-1) x hr(-1) in Group-P, respectively. Indices of both Group-CL (P < 0.001) and Group-DZ (P < 0.05) were smaller than those of Group-P Moreover, clonidine reduced the incidence of uncontrolled movement (P < 0.01), while diazepam reduced the incidence of intraoperative memory and increased the incidence of dream (P < 0.05). Premedication did not affect the incidence of other complications.

CONCLUSION

Both premedicants reduced propofol requirements and exerted beneficial effects on the incidence of some complications during sedation with propofol as an adjunct to regional anesthesia.

[Systemic lupus erythematosus in the pregnant patient. Implications for anesthesia]

A 28-year-old woman with systemic lupus erythematosus and a history of aseptic meningitis, digestive bleeding due to thrombopenia and deep venous thrombosis underwent elective cesarean for transverse presentation at 35 weeks. Preoperative blood work-up showed an antinuclear antibody titre that was slightly positive and steroid treatment was started. Surgery operation was performed with general anesthesia. The outcome was satisfactory even though serious complications can develop during the management of anesthesia in such patients. Systemic lupus erythematosus is a chronic, multisystemic disease that mainly affects women of childbearing age. Antibodies and immunocomplexes play a fundamental role. Given the multiorgan involvement in this disease, preoperative study of the lupus patient should assess all such involvement, including maternal-fetal risk, as well as consider the drug and anesthetic management to be applied. Among the clinical signs that can affect management of anesthesia are the following: aseptic meningitis, high blood pressure, pericarditis, pneumonitis and recurrent venous thrombosis. Anemia, thrombopenia and significantly altered coagulation events are common.

[Total intravenous anesthesia by propofol, fentanyl and ketamine for five cases of acute superior mesenteric artery occlusion]

We report the anesthetic management for emergency surgery of five patients with acute superior mesenteric artery occlusion. Although induction was performed with a combination of propofol, fentanyl and ketamine, their hemodynamics was relatively stable during the induction and maintenance of anesthesia. Immediately after embolectomy, reperfusion of the superior mesenteric artery led to sudden hypotension, requiring the administration of fluids and vasoactive agents in two of four patients. Unfortunately, two of the five patients died of cardiac arrest and multiple organ failure in the early postoperative period. While total intravenous anesthesia with propofol, fentanyl and ketamine may provide stable anesthetic management in patients with superior mesenteric artery occlusion, it must be emphasized that in addition to careful intraoperative management, such patients require intensive and multiple organ care during the postoperative period.

[A case of wide-spread emphysema following the extraction of mandibular third molar under intravenous sedation]

A 45 year-old male underwent lower left third molar extraction under intravenous sedation. During the surgical extraction of the mandibular left impacted third molar using a high-speed air-turbine drill, the patient complained of compression at the level of the right breast without any abnormal vital signs. Radiological investigation and CT scan showed a picture of bilateral, subcutaneous and mediastinal emphysema involving the bilateral face, neck and pectoral area. Following the antibiotic therapy, the drainage was performed through bilateral pectoral incisions by thoracic surgery. The patient recovered within two days and underwent the completion of this surgery under general anesthesia one month later.

Anaesthetic technique for transoesophageal echocardiography in children

OBJECTIVE

To document the safety and efficacy of an anaesthetic technique in paediatric patients undergoing transoesophageal echocardiography (TOE).

METHODS

Prospective descriptive study performed in a children's hospital with all patients undergoing TOE. Topical analgesia of the pharynx was achieved with lidocaine. Anaesthesia was induced with midazolam (25 microg.kg-1), fentanyl (1 microg.kg-1), and propofol (0.5-1 mg.kg-1), followed by a continuous infusion of propofol (5-10 mg.kg-1.h-1).

RESULTS

Thirty patients are reported. The mean age was 11.4 +/- 5.1 years (range 1-22) and weight 40.5 +/- 22.1 kg (range 10-110). All the patients tolerated the procedure well. Two patients experienced brief oxygen desaturations during induction, 10 patients coughed during the procedure, and six patients had significant muscle activity requiring supplemental doses of propofol. None of the patients experienced nausea or vomiting.

CONCLUSION

We conclude that our anaesthetic technique in spontaneously breathing paediatric patients during TOE is effective and appears to be safe in children with heart disease.

[Alterations in left ventricular-arterial coupling and mechanical efficiency produced by remifentanil during cardiac anesthesia]

BACKGROUND

The performance of the cardiovascular system depends on the interaction of the left ventricle and arterial system. An appropriate coupling of these two components is important to quantify the efficiency of myocardium, determined by Ea/Ees. The end-systolic elastance of the left ventricle (Ees) is an index of contractility which is independent of loading conditions, while the arterial end-systolic elastance (Ea) represents the properties of the arterial system. The aim of our study is to investigate the effects of a bolus of remifentanil (R) on myocardial efficiency.

METHODS

In a period of 3 months we examined prospectively the effects of R in a group of 12 patients, ASA IV, 49-75 years old, submitted intraoperatively to cardiac anesthesia for revascularization of myocardium. After induction of anesthesia and before the beginning of surgery, a bolus of R (1 mg/kg/min) was administered and with the use of trans-esophageal echocardiography we determined both the left ventricle end-systolic volume and end-diastolic volume to assess, with different end-systolic arterial pressures, the ventricle elastance (Ees) and arterial elastance (Ea) before and after administration of R.

RESULTS

The present findings indicate that R decreases the ventricular elastance from 6.07 mmHg/ml/m2 to 4.8, with a less decrease of arterial elastance from 3.69 mmHg/ml/m2 to 3.07.

CONCLUSIONS

The results suggest that R preserves a good left ventricular-arterial coupling and mechanical efficiency, despite a little increase of coupling, probably because ventricular and arterial properties are so matched as to minimize the systolic work of the left ventricle.

Investigations using logistic regression models on the effect of the LMA on morphine induced vomiting after tonsillectomy

The effect of intraoperative airway management on postoperative vomiting after tonsillectomy is unknown. Logistic regression was used in a retrospective study to investigate the effect of the laryngeal mask airway (LMA) on a morphine dose-vomiting response curve. Charts were reviewed in 351 children in whom the airway was managed with either a LMA (n=177) or a tracheal tube (n=174). A mean perioperative morphine dose of 0.10 mg.kg(-1) (SD 0.09) was used in 248 children and a further 103 children were given no opioid. One hundred and eighteen of these 248 children vomited (47.6%) compared to 14 of 103 children given no morphine (13.6%). The probability of vomiting was related to morphine dose using logistic regression with both a linear and an E(max) model. Both the calibration (Hosmer-Lemishow goodness of fit chi-squared test lambda(2), P=0.81) and discrimination (area under the receiver operating characteristic plot, AUC ROC=0.67) of the E(max) model were better than the linear model (lambda(2), P=0.49; AUC ROC=0.64). Pharmacodynamic parameter estimates for the Emax model were P(0) (the baseline probability of vomiting) 0.139, P(max) (the maximal probability of vomiting due to morphine) 0.96, ED(50) (morphine dose that induces an effect equivalent to 50% of the logit P(max)) 0.09 mg.kg-1. The probability of vomiting was 50% after morphine 0.125 mg.kg-1. The use of the LMA had no effect on this dose-response curve. A covariate analysis investigating propofol for induction or isoflurane for the intraoperative maintenance of anaesthesia, however, showed that both drugs shifted the curve to the right. The probability of vomiting was 50% after morphine 0.17 mg.kg(-1) and 0.21 mg.kg(-1) for the isoflurane and propofol use curves, respectively. The concomitant use of propofol and isoflurane, but not the use of the LMA, decreases the probability of vomiting due to morphine.

Reversal of rocuronium with edrophonium during propofol versus sevoflurane anesthesia

BACKGROUND

The use of volatile anesthetics for maintenance of anesthesia can enhance the action of non-depolarizing muscle relaxants and interfere with the reversal of neuromuscular blockade. In this study, we studied the antagonism of rocuronium with edrophonium-atropine during propofol- versus sevoflurane-based anesthesia.

METHODS

Following induction of anesthesia with propofol (2-2.5 mg kg(-1), i.v.) and fentanyl (1-2 microg kg(-1) i.v.), rocuronium 0.6 mg kg(-1) i.v. was administered to facilitate tracheal intubation. Patients were then randomized to receive either a propofol infusion (100 microg kg(-1) min(-1)) or sevoflurane (1.0%, end-tidal) in combination with nitrous oxide 66% for maintenance of anesthesia. Neuromuscular blockade was monitored using electromyography at the wrist, and reversed with edrophonium 1.0 mg kg(-1) and atropine 0.015 mg kg(-1) when the first twitch hight (T1) of the train-of-four (TOF) stimulation recovered to 25% of the baseline value. Anesthetic maintenance with propofol or sevoflurane was continued following reversal until a TOF ratio of 0.7 was attained.

RESULTS

The clinical duration of action (i.e., time to 25% T1 recovery) was similar during both propofol- (39.3+/-14.6 min) and sevoflurane-based (48.1+/-19.7 min) anesthesia. However, the reversal time from 25% T1 to TOF ratio of 0.7 was significantly longer with sevoflurane [Median 2.8 (range 0.5-18.8) min] compared with propofol [1.5 (0.75-3) min] (P<0.05).

CONCLUSIONS

We conclude that the clinical duration of action after a single dose of rocuronium, 0.6 mg kg(-1) i.v., was similar during both propofol- and sevoflurane-based anesthesia. However, the reversal of rocuronium-induced residual blockade was slower and more variable in the presence of sevoflurane.

[Anesthetic management of two patients with insulinoma using propofol--in association with rapid radioimmunoassay for insulin]

We experienced anesthetic management of two patients with insulinoma in whom frequent hypoglycemic episodes with blood glucose levels of 39-42 mg.dl-1 had been observed. Each patient received epidural analgesia with a catheter inserted at the T 9/10 intervertebral space. Anesthesia was induced with propofol 80-100 mg and fentanyl 200 micrograms. Tracheal intubation was facilitated with vecuronium 6 mg. Anesthesia was maintained with continuous infusion of propofol and epidural anesthesia. Rapid measurements of immunoreactive insulin (IRI) were useful for localization of insulinoma during surgery. Perioperative plasma glucose levels could be maintained within normal ranges by continuous infusion of glucose. Rebound hyperglycemic episodes were not observed, and IRI was reduced after removal of the insulinoma. General anesthesia using propofol and epidural block is a useful choice for the anesthetic management of patients undergoing an operation for removal of an insulinoma.

Hyperintense signal abnormality in subarachnoid spaces and basal cisterns on MR images of children anesthetized with propofol: new fluid-attenuated inversion recovery finding

BACKGROUND AND PURPOSE

MR imaging is the method of choice for pediatric neuroimaging. Sedation is often needed to suppress patient motion and ensure diagnostic image quality, and propofol is rapidly becoming the preferred anesthetic. The purpose of this study was to document a new finding on fast fluid-attenuated inversion recovery (fast-FLAIR) MR images of children anesthetized with propofol that can be mistaken for subarachnoid space pathologic abnormality.

METHODS

A retrospective analysis was conducted of 55 MR images of the brain for children who ranged in age from 1 week to 12 years. Forty-two patients received chloral hydrate, and 13 received propofol anesthetic. Multiplanar MR images were studied to detect the presence or absence of hyperintense signal (artifact) in the subarachnoid spaces and basal cisterns. The T1 values and null times of chloral hydrate, propofol, and CSF were determined in vitro at room temperature by using an inversion recovery pulse sequence at 1.5 T.

RESULTS

The fast-FLAIR images of all 13 patients who received propofol had hyperintense signal abnormality. For 10 (77%) of 13 patients, this artifact was in the basal cisterns and subarachnoid spaces overlying the brain convexity. For three (23%) of 13 patients, this artifact was in the convexity region only. Two patients underwent follow-up MR imaging with a nonpropofol anesthetic agent, and the artifact resolved. None of the images of the children who received chloral hydrate had this artifact. The T1 value of chloral hydrate was 0.2 s, of propofol was 1.86 s, and of CSF was 2.32 s at room temperature.

CONCLUSION

The fast-FLAIR images of children anesthetized with propofol have artifactual hyperintense signal in the basal cisterns and subarachnoid spaces, and this artifact mimics disease of the subarachnoid space. The T1 value of propofol approaches that of CSF. Depending on the chosen null time, there may be incomplete nulling of signal coming from propofol. To account for this observation, other possible causes include increased CSF pulsation in children creating motion artifact, changes in arterial oxygen concentration intrinsic to propofol or related to the supplemental oxygen normally administered, or changes in CSF protein levels related to propofol binding to proteins for uptake into CSF.

Propofol anesthesia induces phase synchronization changes in EEG

OBJECTIVE

Phase coupling between EEG channel pairs in various frequency bands was evaluated during propofol anesthetic induction and recovery periods.

METHODS

Twenty-three patients participated in the study. Phase synchronization indices based on the Hilbert transform were investigated on frequency bands 0.05-1 Hz, 1-4 Hz, 4-8 Hz, 8-12 Hz and 12-16 Hz for all pairs of the 9 EEG channels covering midline and frontal areas. A straight line was used to approximate the index values as a function of time and the Sign Test statistics were applied to the slope parameters.

RESULTS

Systematic phase synchronization changes were detected. Generally, phase synchronization in the sub-delta band decreased during the induction and increased during the recovery, while the directions were reversed in the alpha band. The changes were dependent on the channel pair. In the delta, theta and beta bands, the changes were aligned more irregularly than in the sub-delta or in the alpha bands. Highly asymmetric behavior between the induction and the recovery periods was also observed in these bands.

CONCLUSIONS

Induction and recovery from propofol anesthesia changes the phase synchronization between the EEG channels. The passband and location-specific behavior of these changes reveals the effects of the anesthetic to the different neural mechanisms.

Extracranial radiosurgery: immobilizing liver motion in dogs using high-frequency jet ventilation and total intravenous anesthesia

PURPOSE

Extracranial radiosurgery requires control of organ motion. The purpose of this study is to quantitatively determine the extent of liver motion in anesthetized dogs with continuous i.v. propofol infusion with or without muscle relaxants and high-frequency jet ventilation.

METHODS AND MATERIALS

Five dogs were used in the experiment. Each dog was restrained while anesthetized in the supine position using an alpha cradle. Surgical metal clips were implanted around the liver periphery so that its motion could be visualized using a fluoroscopic imaging device in a conventional simulator. Initially, two orthogonal simulation films were taken to correlate locations of implanted clips. Two orthogonal views of fluoroscopic images for each anesthetized dog were recorded on a magnetic tape and analyzed from the post-imaging data. Liver motion was documented under the following three conditions: 1) ventilated with a conventional mechanical ventilator, 2) ventilated with a high-frequency jet ventilator, and 3) ventilated with a high-frequency jet ventilator and total muscle paralysis (with vecuronium injection). The maximum liver motion for each dog was analyzed in three orthogonal directions: the inferior-to-superior direction, the anterior-to-posterior direction, and the right-to-left direction.

RESULTS

When the anesthetized dogs were ventilated with a conventional mechanical ventilator, the average liver motions were 1.2 cm in the inferior-to-superior direction, 0.4 cm in the anterior-to-posterior direction, and 0.2 cm in the right-to-left direction, respectively. After the introduction of high-frequency jet ventilation, the average liver motions were reduced to 0.2 cm in the inferior-to-superior direction, 0.2 cm in the anterior-to-posterior direction, and 0.1 cm in the right-to-left direction. The maximum liver motion was dependent on ventilator settings. There was no additional measurable motion reduction with the addition of the muscle relaxant.

CONCLUSION

The liver motion in each anesthetized dog was controlled under 3.0 mm in all directions with the use of high-frequency jet ventilation. No detectable advantage was identified by the injection of muscle relaxant in terms of further reducing the liver motion. The preclinical animal study indicated that the use of high-frequency jet ventilation (HFJV) would be able to limit the liver motion to an extent acceptable for the application of extracranial radiosurgery in humans. Radiosurgery for localized liver tumors warrants further investigation.

Use of remifentanil in a patient with peripartum cardiomyopathy requiring Caesarean section

We describe a case of a 26 yr old primigravida at 39 weeks' gestation, with a diagnosis of peripartum cardiomyopathy, requiring urgent Caesarean section. The patient presented in severe heart failure and active labour. A general anaesthetic, using a target-controlled infusion of propofol and an intravenous infusion of remifentanil, was used to provide stable anaesthesia and analgesia for a successful delivery. The unusual diagnosis of peripartum cardiomyopathy and the potential benefits of the use of remifentanil in high-risk obstetric surgery are discussed.

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.

Myopexy (Faden) results in more postoperative vomiting after strabismus surgery in children

BACKGROUND

Strabismus correction in children is associated with a high incidence of postoperative nausea and vomiting. The purpose of this prospective, double-blind study was to examine the influence of the surgical method for correction of squint on the incidence of postoperative vomiting.

METHODS

One hundred and twenty consecutive children aged 2-12 years, scheduled for elective strabismus surgery, were enrolled in this prospective, double-blind study. A standardised total intravenous anaesthesia was given to all children. The development of perioperative oculocardiac reflex was noted and the number of episodes of vomiting during the first 48 h postoperatively was recorded. At the completion of the study, the children who were operated with myopexy according to Faden, were allocated to a Faden group, those without a myopexy to the non-Faden group. All the patients included in this study were operated on by the same surgeon with standardised techniques.

RESULTS

The Faden group was younger, lighter and the operation time was longer (P<0.05). The incidence of vomiting was greater in the Faden group; 53% versus 12% (P<0.05). The incidence of oculocardiac reflex was similar in both groups; 40% in the Faden versus 28% in the non-Faden group, respectively. The total dose of propofol and alfentanil was similar between the groups. Requirement of analgesics for postoperative pain was similar in both groups. The only independent risk factor for postoperative vomiting was the Faden operation.

CONCLUSION

The surgical method used for strabismus correction in children has a great influence on the incidence of postoperative vomiting. The Faden operation is associated with a very high incidence of postoperative vomiting; this particular group of patients has to be considered as a high risk group for postoperative vomiting and deserves an antiemetic prophylaxis.

High concentration sevoflurane induction of anesthesia accelerates onset of vecuronium neuromuscular blockade

PURPOSE

To investigate neuromuscular block using accelography after administration of vecuronium under sevoflurane 8% induction and maintenance with sevoflurane 2% in adults.

METHODS

Patients were allocated to three groups: (1) group I: anesthesia was induced and maintained with propofol and fentanyl (n= 15), (2) group II: anesthesia was induced with propofol and maintained with N2O(66%)-O2-sevoflurane 2% (n = 15), (3) group III: anesthesia was induced with sevoflurane 8% using a vital capacity inhalation induction and maintained with N2O(66%)-O2-sevoflurane 2% (n = 15). 0.1 mg x kg(-1) vecuronium was used for paralysis three minutes after anesthetic induction and reversed using intravenous 0.04 mg x kg(-1) neostigmine with 0.02 mg kg atropine when the train-of-four (TOF) ratio returned to 25%.

RESULTS

The onset time from initial administration of vecuronium to maximal block in the group III was shorter than that in the groups I and II (139 +/- 35, 193 +/- 35 and 188 +/- 47s, respectively: P < 0.05). The clinical duration from maximal block to 25% recovery of TOF ratio in group II and III was longer than that in the group I (47 +/- 15, 48 +/- 14 and 36 +/- 10 min, respectively: P < 0.05). The reversal times from administration of neostigmine to 75% of TOF ratio in groups II and III were longer than that in the group I (196 +/- 53, 208 +/- 64 and 136 +/- 28s, respectively: P < 0.05).

CONCLUSIONS

Vital capacity inhalation induction of anesthesia with sevoflurane accelerates onset and prolongs duration of vecuronium neuromuscular block compared with propofol-fentanyl anesthesia.

The efficacy of oral clonidine premedication in the prevention of postoperative vomiting in children following strabismus surgery

We evaluated the efficacy of clonidine given orally preoperatively for preventing postoperative vomiting (POV) in children undergoing propofol-nitrous oxide anaesthesia for strabismus surgery. Sixty children, ASA physical status I, aged 2-12 years, received diazepam, 0.4 mg x kg(-1) or clonidine, 4 microg x kg(-1) (n=30 each) orally, in a randomized double-blind manner. These drugs were given 105 min before an inhalational induction of anaesthesia. A complete response, defined as no POV and no need for rescue antiemetic medication, during 0-24 h after anaesthesia was 67% with diazepam and 93% with clonidine, respectively (P=0.024). No clinically adverse event was observed in any of the groups. In summary, pretreatment with oral clonidine enhances the antiemetic efficacy of propofol for the prevention of POV after paediatric strabismus surgery.