Summary

Background and objective: When continuous infusions of neuromuscular blocking drugs are administered during lengthy interventions and no routine antagonism of their effects is applied, there is a dramatic incidence of residual curarization. We have examined whether the use of neuromuscular transmission monitoring results in differences in the incidence of postoperative residual curarization, the use of antagonist agents, and the endotracheal extubation rate and outcome after continuous infusion of rocuronium in patients undergoing off-pump coronary artery bypass surgery.

Methods: Twenty patients were assigned to group 1 (n = 10, non-blinded neuromuscular transmission monitoring) or group 2 (n = 10, blinded neuromuscular transmission monitoring). In group 1, patients were given rocuronium at an infusion rate of 6 μg kg−1 min−1. The rate was manually adjusted in order to maintain T1/T0 at 10%. In group 2, a rocuronium infusion was started 30 min after induction of anaesthesia, at a rate of 6 μg kg−1 min−1; this rate was left unchanged during surgery. The rocuronium infusion was discontinued on completion of all vascular anastomoses; propofol was stopped at the beginning of closure of the subcutis and pirinitramide (piritramide) 15 mg was administered intravenously. Remifentanil was discontinued at the beginning of skin closure and neostigmine (50 μg kg−1) administered at the end of surgery when the train-of-four ratio was <0.9 in group 1, and routinely in group 2. A 20 min test period for spontaneous ventilation was allowed once surgery had been accomplished. When the train-of-four ratio was ≥0.9 (group 1), patients were extubated if also breathing spontaneously, fully awake and able to follow commands. When they met the clinical criteria for normal neuromuscular function after induced blockade, patients in group 2 were extubated when fully awake and able to follow commands.

Results: In group 1, the rate of rocuronium infusion required to keep T1/T0 at 10% was 5 ± 1.9 μg kg−1 min−1; this was not significantly different from the fixed rate in group 2 (P = 0.15). One patient in group 2 was excluded. Eight out of 10 and eight out of nine patients in groups 1 and 2, respectively, reached the extubation criteria. Three out of eight, and five out of eight, patients from groups 1 and 2, respectively, were extubated in the operating room. At that time of endotracheal extubation, all three patients from group 1, but only four of the five patients from group 2 had a train-of-four ratio ≥0.9. In group 2, one patient was reintubated in the intensive care unit. The incidence of pharmacological reversal was high in group 1.

Conclusions: Although we found no additional benefit of using neuromuscular transmission monitoring, it seems an absolute necessity for safety reasons. Pharmacological antagonism was mandatory. However, in our opinion, it is not wise routinely to perform immediate postoperative extubation in off-pump coronary artery bypass surgery.

Summary

Background and objective: In clinical trials, autoregulation and carbon dioxide reactivity are preserved during propofol anaesthesia. Paradoxical increases of blood flow velocity during induction of anaesthesia could be demonstrated in patients with brain tumours. This study evaluates the effects of propofol on cerebral blood flow velocity in patients undergoing surgery for brain tumours and vascular malformations.

Methods: Changes in cerebral blood flow velocity after the administration of propofol were assessed using bilateral 2 MHz transcranial Doppler probes in 47 patients undergoing surgery for brain tumours and in 22 patients undergoing surgery for aneurysms and angiomas.

Results: Flow reduction after propofol was slightly less pronounced on the side of the tumour; in patients with cerebrovascular lesions, no difference between the two sides was detectable. After the administration of propofol a flow increase was present on the side of the tumour in 2 patients. In 3 patients with angiomas, the flow decrease after the administration of propofol was less pronounced on the side of the angioma. Neither observation gave statistical proof of abnormality.

Conclusions: The flow changes after propofol may give a hint of cerebrovascular reactivity. Further investigations should focus on combined measurements of cerebral autoregulation and carbon dioxide reactivity and should focus on patients with impaired consciousness to test for reliability.

Summary

Background and objective: In recent years, a large number of airway devices have been introduced into clinical practice as adjuncts to the management of the difficult airway. The purpose of this study was to evaluate the practices of Israeli anaesthetists in specific clinical situations and their familiarity with the use of a variety of airway devices and techniques.

Methods: A survey developed in our institution was sent to 300 attending anaesthetists representing all board-certified anaesthetists practising in Israel.

Results: Of the 153 respondents, 75% belonged to university hospitals. Ninety-six percent were skilled with laryngeal mask airways and 73% with fibreoptics. Seventy percent preferred regional anaesthesia with anticipated difficult intubation, continuation of anaesthesia with a laryngeal mask with failed intubation and a laryngeal mask for impossible mask ventilation. For the airway scenarios, awake fibreoptic, awake direct laryngoscopy, intubation under inhalation anaesthesia and tracheostomy were shared equally.

Conclusions: There is a high degree of adherence by Israeli anaesthetists to the American Society of Anesthesiologists' difficult airway algorithm. Current airway management practice patterns in Israel are presented.

Summary

Background and objective: Both chronic occupational exposure to volatile anaesthetic agents and acute in vitro exposure of neutrophils to isoflurane have been shown to inhibit the rate of apoptosis of human neutrophils. It is possible that inhibition of neutrophil apoptosis arises through delaying mitochondrial membrane potential collapse. We assessed mitochondrial depolarization and apoptosis in unexposed neutrophils and neutrophils exposed to sevoflurane in vivo.

Methods: A total of 20 mL venous blood was withdrawn pre- and postinduction of anaesthesia, the neutrophils isolated and maintained in culture. At 1, 12 and 24 h in culture, the percentage of neutrophil apoptosis was assessed by dual staining with annexin V-FITC and propidium iodide. Mitochondrial depolarization was measured using the dual emission styryl dye JC-1.

Results: Apoptosis was significantly inhibited in neutrophils exposed to sevoflurane in vivo at 24 (exposed: 38 (12)% versus control: 28 (11)%, P = 0.001), but not at 1 or 12 h, in culture. Mitochondrial depolarization was not delayed in neutrophils exposed to sevoflurane.

Conclusions: The most important findings are that sevoflurane inhibits neutrophil apoptosis in vivo and that inhibition is not mediated primarily by an effect on mitochondrial depolarization.

Summary

Background and objective: This prospective, randomized, controlled study evaluated the effects on oxygenation by applying a selective and patient-specific value of positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation.

Methods: Fifty patients undergoing thoracic surgery under combined epidural/general anaesthesia were randomly allocated to receive zero PEEP (Group ZEEP, n = 22), or the preventive application of PEEP, optimized on the best thoracopulmonary compliance (Group PEEP, n = 28). Patients' lungs were mechanically ventilated with the same setting during two- and one-lung ventilation (FiO2 = 0.5; VT = 9 mL kg−1, inspiratory : expiratory time = 1 : 1, inspiratory pause = 10%).

Results: Lung-chest wall compliance decreased in both groups during one-lung ventilation, but patients of Group PEEP had 10% higher values than patients with no end-expiratory pressure (ZEEP) applied – Group ZEEP (P < 0.05). During closed chest one-lung ventilation, the PaO2 : FiO2 ratio was lower in Group PEEP (232 ± 88) than in Group ZEEP (339 ± 97) (P < 0.05); but no further differences were reported throughout the study. No differences were reported between the two groups in the need for 100% oxygen ventilation (10 patients of Group ZEEP (45%) and 14 patients of Group PEEP (50%) (P = 0.78)) or re-inflation of the operated lung during surgery (two patients of Group ZEEP (9%) and three patients of Group PEEP (10%) (P = 0.78)). Postanaesthesia care unit discharge required 48 min (25th–75th percentiles: 32–58 min) in Group PEEP and 45 min (30–57 min) in Group ZEEP (P = 0.60).

Conclusions: The selective application of PEEP to the dependent, non-operated lung increases the lung–chest wall compliance during one-lung ventilation, but does not improve patient oxygenation.

Summary

Background and objective: Previous studies have shown existence of inconsistent data concerning the use of auditory-evoked potential (AEP) and electroencephalogram (EEG) changes to measure the depth of anaesthesia in regimens involving the use of opioids. The present studies characterize the effects of fentanyl on those responses in rats.

Methods: The effects of a bolus of fentanyl (6–10 μg kg−1 intravenously) alone or following naloxone (100 μg kg−1 intravenously) were examined using brain responses in rats during light anaesthesia with either propofol (20–30 mg kg−1 h−1) or isoflurane (0.8%). Electrophysiological data were recorded using silver ball electrodes. The rats' tracheas were intubated and a femoral artery cannula was inserted to monitor blood pressure. Body temperature, respiratory and pulse rate, and pedal withdrawal data were also collected. Parameters measured before and following administration of naloxone and fentanyl or of fentanyl alone were compared using repeated-measures ANOVA.

Results: Fentanyl significantly increased the latency of the major peak from the AEP during propofol and isoflurane anaesthesia (F = 13.2 and 13.5, respectively; P < 0.05) and the amplitude differential between two waveform complexes, and the second differential index (F = 28.3 and 57.2, respectively; P < 0.01). The spectral edge frequency and median frequency from the EEG tended to increase. These effects were abolished by the prior administration of naloxone.

Conclusions: These excitatory effects were inconsistent with the classical concept of brain activity depression indicating a deepening of anaesthesia.

Summary

Background and objective: This study was designed to compare the haemodynamic, electrophysiological and pharmacodynamic effects of three selective inhibitors of the different isoenzyme forms of phosphodiesterase (PDE) on ischaemia-induced dysrhythmias in the anaesthetized rat. The drugs used were pimobendan, a selective PDE III inhibitor, rolipram, a selective PDE IV inhibitor, and zaprinast, a selective PDE V inhibitor.

Methods: The coronary artery was occluded 15 min after commencing drug administration, and myocardial ischaemia was maintained for 30 min during which the heart rate and mean arterial pressure were recorded. cAMP and cGMP were determined by radioimmunoassay.

Results: Pretreatment with rolipram decreased the duration of ventricular tachycardia without any change in the incidences of dysrhythmias or the mortality rate. This drug did not modify ventricular content of adenosine 3′,5′-cyclic monophosphate (cAMP) or guanosine 3′,5′-cyclic monophosphate (cGMP). Pimobendan (1 mg kg−1 + 0.1 mg kg−1 min) decreased the duration of ventricular tachycardia. This dose of pimobendan and zaprinast (1 mg kg−1 + 0.1 mg kg−1 min−1) increased the incidence rate of ventricular fibrillation following coronary artery ligation and the mortality rate. Moreover, both drugs increased cGMP in the ventricle.

Conclusions: The results demonstrated that pimobendan and zaprinast increased the incidence of dysrhythmias and the mortality rate, which was accompanied by an increase in the ventricular content of cGMP. Rolipram decreased the duration of ventricular tachycardia without a change in the cyclic nucleotide content or in the mortality rate.

Summary

Background: In this prospective randomized study we tested the hypothesis that use of more cyclo-oxygenase 2 (COX 2)-selective non-steroidal anti-inflammatory drugs (NSAIDs) can reduce perioperative blood loss compared with non-selective NSAIDs.

Methods: Data from 200 patients who underwent total hip replacement were studied. Two NSAIDs were compared: indomethacin 50 mg (n = 82) and meloxicam 15 mg (n = 86). Both NSAIDs were given orally 1 h before surgery.

Results: The two groups were not different with respect to age, gender, ASA class or duration of surgery. When indomethacin was used preoperatively, intraoperative blood loss was 623 ± 243 mL (mean ± SD) and postoperative blood loss 410 ± 340 mL. After meloxicam, these values were 524 ± 304 mL and 358 ± 272 mL, respectively. Total perioperative blood loss after meloxicam was 17% (P < 0.05) less than that observed after indomethacin.

Conclusion: Perioperative blood loss after meloxicam is less than after indomethacin. These in vivo findings are consistent with in vitro results using selective COX 2 NSAIDs.

Summary

Background and objective: Preoperative bedside screening tests for difficult tracheal intubation may be neither sensitive nor specific enough for clinical use. The aim was to investigate if a combination of the Mallampati classification of the oropharyngeal view with either the thyromental or sternomental distance measurement improved the predictive value.

Methods: A total of 212 (109 male, 103 female) non-obstetric surgical patients, aged >18 yr, undergoing elective surgical procedures requiring tracheal intubation were assessed preoperatively with respect to the oropharyngeal (modified Mallampati) classification, thyromental and sternomental distances. An experienced anaesthetist, blinded to the preoperative airway assessment, performed laryngoscopy and graded the view according to Cormack and Lehane's classification.

Results: Twenty tracheal intubations (9%) were difficult as defined by a Cormack and Lehane Grade 3 or 4, or the requirement for a bougie in patients with Cormack and Lehane Grade 2. Used alone, the Mallampati oropharyngeal view, and thyromental and sternomental distances were associated with poor sensitivity, specificity and positive predictive values. Combining the Mallampati Class III or IV with either a thyromental distance <6.5 cm or a sternomental distance <12.5 cm decreased the sensitivity (from 40 to 25 and 20%, respectively), but maintained a negative predictive value of 93%. The specificity and positive predictive values increased from 89 and 27% respectively for Mallampati alone to 100%.

Conclusions: The findings suggest that the Mallampati classification, in conjunction with measurement of the thyromental and sternomental distances, may be a useful routine screening test for preoperative prediction of difficult tracheal intubation.

Summary

Background and objective: Our hypothesis was that fenoldopam, a selective DA1 agonist, would protect against rhabdomyolysis-induced renal injury.

Methods: We studied the effects of intravenous fenoldopam (0.1–1.0 μg kg−1 min−1) or saline on renal blood flow and function in 10 anaesthetized Labrador dogs in whom rhabdomyolysis and myoglobinuric acute renal failure had been induced by administration of glycerol 50% (10 mL kg−1) intramuscularly. Haemodynamic measurements including renal blood flow and derived parameters of renal function including creatinine clearance were recorded before and for the 30 min following glycerol injection, and during the 3 h following commencement of each infusion. Serum malondialdehyde concentrations were measured before and 15 min after glycerol intramuscularly, and 30 and 150 min after commencement of the infusion.

Results: In the fenoldopam group, creatinine clearance was less than placebo at 1 and 2 h after commencing the infusion (12.7 ± 11.5 versus 31.3 ± 9.9 mL min−1, P = 0.04; 8.5 ± 5.3 versus 20.1 ± 7.4 mL min−1, P = 0.03). A 140-fold increase in serum malondialdehyde concentration occurred in one dog (fenoldopam group).

Conclusion: Fenoldopam increased the severity of the renal injury in this canine model of myoglobinuric acute renal failure.

Summary

Background and objective: We conducted an open, prospective, randomized study to compare the efficacy, safety and recovery characteristics of remifentanil or propofol during monitored anaesthesia care in patients undergoing colonoscopy.

Methods: Forty patients were randomly assigned to receive either propofol (1 mg kg−1 followed by 10 mg kg−1 h−1, n = 20) or remifentanil (0.5 μg kg−1 followed by 0.2 μg kg−1 min−1, n = 20). The infusion rate was subsequently adapted to clinical needs.

Results: In the propofol group, arterial pressure and heart rate decreased significantly from the baseline. These variables remained unchanged in the remifentanil group, but hypoventilation occurred in 55% of patients. Early recovery was delayed in the propofol group (P < 0.002). Recovery of cognitive and psychomotor functions was faster in the remifentanil group. Fifteen minutes after anaesthesia, the Digit Symbol Substitution Test score was 28.6 ± 12.8 versus 36.2 ± 9.4 and the Trieger Dot Test score was 25.6 ± 8.1 versus 18.7 ± 4.1 in the propofol and remifentanil groups, respectively (both P < 0.05). Patient satisfaction, using a visual analogue scale, was higher in the propofol group (96 ± 7 versus 77 ± 21, P < 0.001).

Conclusions: Remifentanil proved efficient in reducing pain during colonoscopy. Emergence times were shorter and the recovery of cognitive function was faster with remifentanil compared with propofol. Remifentanil provided a smoother haemodynamic profile than propofol; however, the frequent occurrence of remifentanil-induced hypoventilation requires the cautious administration of this agent.

Summary

Background and objective: We investigated the following aspects of pharmacokinetic-guided total intravenous anaesthesia with remifentanil and propofol in patients undergoing surgical myocardial revascularization: anaesthetic efficacy, haemodynamic effects, impact on extubation of the trachea and analgesia after operation.

Methods: Thirty-two patients undergoing on-pump coronary bypass surgery received intravenous anaesthesia with remifentanil and propofol. Both drugs were dosed and titrated based on computer-assisted pharmacokinetic models to maintain constant plasma concentrations. The propofol target plasma concentration was 1.2 μg mL−1 throughout the procedure. A remifentanil target plasma concentration of 8 ng mL−1 was achieved over 2 min for induction. After tracheal intubation, the opioid plasma concentration was reduced to 4 ng mL−1, and then titrated up to 8 ng mL−1 during surgery. Postoperative analgesia was managed with remifentanil infusion until 4 h after tracheal extubation, and a continuous infusion of tramadol was started 1 h before the remifentanil was stopped.

Results: After induction of anaesthesia, heart rate (−20%) and cardiac index (−6%) decreased significantly. No hypotensive episodes (mean arterial pressure <60 mmHg) occurred. Intraoperative haemodynamics were stable. Three cases of myocardial ischaemia were detected: two by transoesophageal echocardiography and one with ST-segment monitoring. The duration of postoperative mechanical ventilation of the lungs was 95 ± 13 min and the time to extubation was 150 ± 18 min. Postoperative analgesia was satisfactory in all patients.

Conclusions: Pharmacokinetic-based total intravenous anaesthesia with remifentanil and propofol provides adequate anaesthesia during coronary surgery with cardiopulmonary bypass and allows safe early extubation after operation.

Summary

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 χ2-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 μg kg−1 min−1) than with additional propofol (0.31 ± 0.20 μg kg−1 min−1). The propofol infusion rate was 123 ± 48 μg 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.

Summary

Background and objective: It has been suggested that dexamethasone potentiates the sensory block produced by bupivacaine when both drugs are loaded in microspheres. The aim of the study was to evaluate the effect of dexamethasone on the brachial plexus block obtained with plain bupivacaine and bupivacaine-loaded microspheres.

Methods: Dexamethasone alone (Group 5) or added to plain bupivacaine (75 mg) with (Groups 3 and 4) and without pH correction (Group 2) was compared with plain bupivacaine (75 mg; Group 1). The effect of a small dose of dexamethasone (0.42 mg) was then evaluated on the brachial plexus block obtained with bupivacaine (750 mg) as bupivacaine-loaded microspheres (Group 6). Dexamethasone was added either in the suspending medium (Group 7) or incorporated with bupivacaine into microspheres (Group 8). The motor block was evaluated in a plexus brachial sheep model.

Results: Dexamethasone alone did not produce any motor block. When added to plain bupivacaine without pH correction, complete motor block could not be obtained. When the pH was corrected, addition of dexamethasone to plain bupivacaine seemed to delay the onset of motor block and did not prolong its duration, and it had no effect on the pharmacokinetics of bupivacaine. With bupivacaine-loaded microspheres, the duration of complete motor block was reduced when a small dose of dexamethasone was added in the suspending medium. However, the duration of motor block was significantly prolonged when dexamethasone was incorporated with bupivacaine into microspheres.

Conclusions: Despite the delayed onset of motor block, the incorporation of dexamethasone in bupivacaine-loaded microspheres dramatically increases the duration of action (700 ± 485–5160 ± 2136 min), which could be clinically relevant when such a drug-delivery system will be available.

Summary

Background and objective: The aim was to determine the effect of acute and chronic administration of 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, on the righting reflex ED50 and the minimum alveolar concentration during sevoflurane anaesthesia in rats.

Methods: 7-Nitroindazole was acutely (0, 50 and 100 mg kg−1) and chronically (0 and 150 mg kg−1 day−1, 4 days) administered to rats. After the preparation, the minimum alveolar concentration and the righting reflex ED50 were measured. The concentration of cGMP in the brain, cerebellum and spinal cord was also measured.

Results: Acute administration reduced the minimum alveolar concentration (50 mg kg−1, 58.8% (95% CI: 50.3–67.3%) of the baseline value, P < 0.01; 100 mg kg−1, 55.8 (46.9–64.7), P < 0.01) and the righting reflex ED50 (50 mg kg−1, 27.2 (17.2–37.2), P < 0.01; 100 mg kg−1, 14.3 (6.6–22.0), P < 0.01). Chronic administration did not reduce the minimum alveolar concentration; however, it reduced the righting reflex ED50 (65.3 (52.9–77.7), P < 0.01). Overall, the reduction in minimum alveolar concentration in the acute and chronic protocol did not correlate with that of the righting reflex ED50. 7-Nitroindazole (100 mg kg−1, acute) reduced the cGMP concentration within the cerebellum by 55.4%; however, it did not decrease concentrations in the brain or spinal cord.

Conclusions: Different mechanisms are responsible for the observed alterations to the minimum alveolar concentration and the righting reflex ED50 following treatment with 7-nitroindazole. The nitric oxide–cGMP pathway might play a less important role in the determination of minimum alveolar concentration than the righting reflex ED50.

Summary

Background and objective: Intraperitoneal administration of a local anaesthetic in combination with an opioid, for the relief of postoperative pain, has already been reported except after laparoscopic cholecystectomy. This study was aimed at assessing the analgesic effect of the intraperitoneal administration of bupivacaine and morphine in patients undergoing laparoscopic cholecystectomy.

Methods: At the end of laparoscopic cholecystectomy, in a double-blind, randomized manner, one of the following injections was given intraperitoneally. There were 30 patients in each group: Group 1, physiological saline 30 mL; Group 2, bupivacaine 0.25% 30 mL; Group 3, bupivacaine 0.25% 30 mL plus morphine 2 mg. In addition, Group 2 received 2 mg intravenous (i.v.) morphine in 2 mL saline, and Groups 1 and 3, 2 mL saline intravenously. Patients' postoperative pain was evaluated using a visual analogue scale and a verbal rating score. The postoperative analgesic requirement was assessed by the total dose of metamizol administered by an i.v. patient-controlled analgesia (PCA) device. Pain, vital signs, supplemental analgesic consumption and side-effects were recorded for all patients for 24 h.

Results: There were no differences between the three groups regarding pain scores (at rest and coughing) during the study except in the first 2 h, when scores were lower for patients receiving intraperitoneal bupivacaine plus i.v. morphine (P < 0.05). Supplemental consumption of metamizol was significantly lower (P < 0.05) in Group 3 than in Group 1 during the first 6 h after surgery. However, the cumulative doses of metamizol were also lower in Group 2 than in Groups 1 and 3 over the entire study (2025 ± 1044 mg vs. 4925 ± 1238 and 4125 ± 1276 mg; P < 0.05).

Conclusions: In patients undergoing laparoscopic cholecystectomy, the intraperitoneal administration of morphine plus bupivacaine 0.25% reduced the analgesic requirements during the first 6 postoperative hours compared with the control group. However, the combination of intraperitoneal bupivacaine 0.25% and i.v. morphine was more effective for treatment of pain after laparoscopic cholecystectomy.

Summary

Background and objective: Previous studies have shown that L-type voltage-sensitive Ca2+ channel blocking agents increased and the L-type Ca2+ channel activator Bay K 8644 reduced the general anaesthetic potency in animals. As the bispectral index correlates with the depth of sedation, we examined whether L-type Ca2+ channel blocking agents affect the bispectral index.

Methods: Thirty hypertensive patients (systolic arterial pressure >160 mmHg) presenting for total intravenous anaesthesia with propofol, fentanyl and ketamine were recruited. Bispectral index monitoring was commenced directly the patients arrived in the operating theatre. All patients were given either nicardipine or diltiazem intravenously at the discretion of the anaesthesiologist in charge.

Results: Twenty-three and seven patients received nicardipine or diltiazem, respectively. The bispectral index level (mean (95% confidence interval)) did not change with either drug. In the nicardipine group, the bispectral index at 0, 5, 10 and 15 min was 55 (52–58), 55 (51–59), 55 (52–59) and 56 (53–59), respectively. In the diltiazem group, values were 59 (48–71), 60 (51–70), 61 (52–71) and 61 (50–72), respectively. Both L-type Ca2+ channel blocking agents significantly decreased arterial pressure.

Conclusions: Clinical doses of nicardipine and diltiazem do not alter the bispectral index during general anaesthesia.

Summary

Background and objective: This study was designed to assess the conditions for endotracheal intubation or insertion of a laryngeal mask airway following an inhalational induction using 8% sevoflurane and nitrous oxide without the use of muscle relaxants or opioids.

Methods: There were two groups: 30 children had endotracheal intubation and 30 children had a laryngeal mask airway inserted. Induction of anaesthesia was accomplished using an inspiratory concentration of sevoflurane 8% in a nitrous oxide and oxygen mixture. After an end-expiratory concentration of sevoflurane of at least 4% had been reached, when the pupils were miotic and centred, the trachea was intubated or a laryngeal mask inserted. The time to loss of consciousness and successful airway management was recorded. Jaw relaxation, movements, visibility, and position of the vocal cords and vital parameters were monitored.

Results: Jaw relaxation was complete in all children. The vocal cords were completely visible in all patients of the tracheal intubation group, whereas vocal cord relaxation was incomplete in five children. Nevertheless, all children had an atraumatic intubation or insertion of the laryngeal mask without the use of a muscle relaxant. Vital signs were stable in both groups. There were no cases of restlessness and/or postoperative shivering. Four patients in the endotracheal group (13.3%) were nauseous and three (10%) vomited, while two children (6.6%) in the laryngeal mask group experienced nausea and vomiting.

Conclusions: Induction with sevoflurane in nitrous oxide and oxygen leads to fast loss of consciousness and provides ideal conditions for managing the airway without supplemental opioids or muscle relaxants. Furthermore, sevoflurane using this technique was very well tolerated, indicated by high haemodynamic stability and a reduced rate of postoperative restlessness, shivering, nausea and vomiting.

Summary

Background and objective: Little is known about the interaction of newer volatile anaesthetics with endothelial eicosanoid production. Sevoflurane may possibly reduce prostacyclin formation. Thus, we compared the influences of sevoflurane and isoflurane on endothelial prostacyclin production.

Methods: Production of prostacyclin of human umbilical vein endothelial cells was measured by the ELISA technique under basal conditions and after stimulation with calcium ionophore A 23187 10 μmol or histamine 0.1 μmol in the absence and presence of 1 and 2 minimal alveolar concentrations (MAC) of sevoflurane or isoflurane.

Results: The basal production of prostacyclin was unaffected by the volatile anaesthetics. Stimulation of endothelial cells increased prostacyclin formation 3–5-fold. Sevoflurane at 2 MAC, but not at 1 MAC, could reduce stimulated prostacyclin production by about half (P < 0.05). Isoflurane had no inhibitory effect. Inhibition of cyclo-oxygenase function by acetylsalicylic acid abolished the induced burst of prostacyclin formation completely.

Conclusions: Sevoflurane, but not isoflurane, can reduce stimulated endothelial prostacyclin production in a concentration-dependent manner. Because at least 2 MAC of sevoflurane were required, this effect should be of minor importance under clinical conditions of balanced anaesthesia.

Summary

Background and objective: Remifentanil has unique pharmacokinetics that might allow faster recovery after neurosurgery. We investigated the effects of a propofol/sufentanil versus a remifentanil/propofol regimen on the primary end-point tracheal extubation time.

Methods: In the Neurosurgery Department of a University Hospital, 36 patients awaiting craniotomy for supratentorial tumour resection were randomly assigned to one of two study groups. In the sufentanil/propofol group, anaesthesia was induced with 0.5 μg kg−1 sufentanil and 1–2 mg kg−1 propofol. Propofol infusion and boluses of sufentanil were administered for maintenance. In the remifentanil/propofol group, anaesthesia was started with an infusion of remifentanil (0.2–0.35 μg kg−1 min−1) and a bolus of propofol (1.5–2 mg kg−1). Patients received a propofol infusion and a remifentanil infusion for maintenance of anaesthesia. Recovery times were taken from cessation of the propofol infusion. In addition, data about self-reported nausea and vomiting, pain and analgesic requirements were collected.

Results: Patients in the remifentanil/propofol group were extubated earlier (mean times 6.4 (±SD 4.7) versus 14.3 (±9.2) min; P = 0.003). The two groups were similar with respect to postoperative nausea and vomiting, and patient-reported pain scores. Fifty per cent of the remifentanil/propofol patients and 88% of the sufentanil/propofol patients required no analgesics within 1 h after operation (P= 0.03).

Conclusions: The remifentanil/propofol regimen provided quicker recovery. The two regimens were similar in terms of postoperative nausea and vomiting and patient-reported pain scores, but patients in the remifentanil/propofol group required more analgesics within 1 h postoperatively.