Summary

Background and objective: Measurement of central blood volumes (CBV), such as global end-diastolic volume (GEDV) and right ventricular end-diastolic volume (RVEDV) are considered appropriate estimates of intravascular volume status. However, to apply those parameters for preload assessment in mechanically ventilated patients, the influence of tidal volume (TV) and positive endexpiratory airway pressure (PEEP) on those parameters must be known. Methods: In 13 mechanically ventilated piglets, the effect of low (10 mL kg−1) and high (20 mL kg−1) TVs on CBV was investigated in absence and presence of PEEP (0 and 15 cmH2O). GEDV, RVEDV, right heart (RHEDV) and left heart end-diastolic volume (LHEDV) were measured by thermodilution. Blood flow on the descending thoracic aorta measured with an ultrasonic flow-probe served to determine stroke volume (SV). Measurements were performed during baseline conditions, after volume loading with previously extracted haemodilution blood (20 mL kg−1) and following haemorrhage (30 mL kg−1). Results: Application of PEEP decreased GEDV and SV significantly (P < 0.05). Augmenting TV did not reduce GEDV systematically, but significantly reduced SV (P < 0.05). Changes in ventilator settings only influenced RVEDV following volume loading (P < 0.05). RHEDV and LHEDV decreased following application of PEEP, but only RHEDV decreased after augmenting TV at baseline and following volume loading. Correlation of SV with parameters of CBV was r = 0.487 (P < 0.01) for GEDV, r = 0.553 (P < 0.01) for RVEDV, r = 0.596 (P < 0.01) for RHEDV and r = 0.303 (P < 0.01) for LHEDV. Conclusion: Application of PEEP decreases CBV and SV. Augmenting TV reduces SV but not CBV. There is a moderate correlation between parameters of CBV and cardiac performance.

Summary

Background and objective: We compared the laryngeal mask airway (LMA™) and the laryngeal tube (LT®) with the newly introduced perilaryngeal airway (CobraPLA®, PLA) with regard to haemodynamic responses induced by airway insertion, clinical performance and occurrence of postoperative sore throat after short surgical procedures. Methods: After premedication, 90 ASA I–II patients awaiting short surgical procedures were randomized to receive, LMA, LT or PLA. Anaesthesia was induced with intravenous propofol (2.5 mg kg−1) and mivacurium (0.2 mg kg−1). Number of attempts, time of insertion of the device, any other unwanted effect, mean aterial pressure, heart rate, oxygen saturation and end-tidal carbon dioxide were recorded. At the end of surgery, the cuff of the device was immediately deflated and the airway device was removed. The device was examined and noted for the presence of visible blood. Patients were asked to rate their throat soreness, dysphonia and dysphagia 1 and 24 h postoperatively. Results: There were no differences in haemodynamic variables. Insertion times for the devices were similar (LMA: 20 ± 11 s, LT: 19 ± 14 s and PLA: 21 ± 12 s.) The success rates at first insertion were lower in the (LMA group (57%) when compared with the PLA (97%, P < 0.05). The number and type of airway interventions for achieving an effective airway were similar. When the airways were removed 50% of the PLA devices had positive blood traces, while only 17% of the LMA and LT devices had positive blood traces (P < 0.01). Fifty percent of the patients suffered from a sore throat in the PLA group, which was significantly higher than in the LMA and LT groups (P < 0.05). Conclusion: We conclude that haemodynamic, ventilation and oxygenation variables throughout the surgery were similar with, LMA, LT and PLA, but LT and PLA were easier to insert; LMA and LT caused less mucosal trauma.

Summary

Background and objective: Unilateral spinal anaesthesia is a useful anaesthesia technique in lower abdominal surgery, especially in an outpatient setting. Patient posture is pivotal in the achievement of unilateral anaesthesia. Nevertheless, no studies have elucidated the influence of patient posture during the anaesthetic injection on unilaterality. Thus, the aim was to compare the effect of patient posture, during the induction phase of spinal anaesthesia, on block characteristics. Methods: Eighty patients, ASA I–II, scheduled for unilateral hernioplasty were randomized into two groups. Anaesthesia was performed in lateral position in Group 1 (G1) with operative side down and in sitting position in Group 2 (G2) whose patients were then immediately turned on their lateral side. All patients were maintained for 20 min in lateral position with their operative side down. Hyperbaric bupivacaine 1% 10 mg were used. Results: Unilateral anaesthesia was seen in 80% (32/40) and 12.5% (5/40) of G1 and G2, respectively. The readiness for surgery was faster in G1 (P < 0.0001). The motor block in the non-operative side was stronger in G2 (P < 0.0001). The offset of sensory block was faster in G1 (P = 0.0001). The offset of motor block was slower in G1 (P = 0.0008). The time for voiding was shorter in G1, although not significant. Conclusions: Lateral posture during the induction of spinal anaesthesia is pivotal for a higher success of unilateral block, a fast readiness to surgery, and a fast recovery. Therefore, this technique can be considered feasible and time-saving for lower abdominal surgery.

Summary

Background and objective: The reasons for coagulopathy may be multiple and the identification of the underlying cause is often difficult. Recently, we identified two patients showing characteristics of heparin overdose during surgery. We hypothesised that filling a Shaldon dialysis catheter with heparin prior to closure, so-called heparin lock, might have triggered this coagulation disorder. Therefore, the aim of this in vitro study was to show whether this procedure can lead to an iatrogenic administration of heparin. Methods: A Shaldon catheter (GamCath®; Joka Kathetertechnik, Hechingen, Germany) was hung up in a container filled with NaCl solution 0.9% 5 mL and a heparin lock was simulated. Instead of using heparin solution we injected 1 mL of a KCl solution (1 mol L−1) into the Shaldon catheter, because the measurement of the potassium concentration is faster and more reliable than that of heparin. Ten measurements were taken after fast (0.5 s) and slow (3 s) injection speeds. Results: Although the catheter volume is specified as 1.07 mL, an amount up to 0.51 mL KCl solution on average was detectable in the solution after locking the catheter with 1 mL KCl solution. Conclusions: Following a heparin lock a considerable amount of the injected solution is accidentally administered to the patient. Only 49.1% of the injected volume may remain in the Shaldon catheter. This could lead to an increased risk of coagulopathy.

Summary

Background and objective: Stimulating the vagus nerve reduces pain. The purpose of this study was to evaluate the effect of a Valsalva manoeuvre, which stimulates the vagus nerve, on perception of pain during peripheral venous cannulation in adult patients. Methods: This was a prospective randomized clinical trial. One hundred and ten patients scheduled for elective surgery were randomly divided into two groups. Half of the patients, Group A, underwent venepuncture during a Valsalva manoeuvre and the other half of the patients, Group B, underwent venepuncture without performing a Valsalva manoeuvre. Patients made a pain assessment using a 0–10 point numerical rating scale. Results: The numerical rating scale score was 1.5 ± 1.2 for Group A and 3.1 ± 1.9 for Group B, the difference being statistically significant (P < 0.0001). Conclusions: On the basis of data from this study, the Valsalva manoeuvre may be of the value before venous cannulation as a simple and practical method to reduce pain from venous cannulation.

Summary

Backgrounds: Microglial cells play an important role in the pathophysiology of intracerebral haemorrhage. We have examined the possible influence of sevoflurane on the reactivity of microglial cells during intracranial haemorrhage. Methods: Forty adult male rats were divided into two groups. All animals were anaesthetized with fentanyl, dehydrobenzperidol and midazolam. In the experimental group animals additionally received sevoflurane 2.2 vol% end-tidal concentration. Intracranial haemorrhage was produced through infusion of blood into the striatum. The microglial cell population (numerical density of immunoreactive cells and their distribution) was assessed on days 1, 3, 7, 14 and 21 after producing a haematoma using antibodies OX42 and OX6. Results: In the control group significant differences in the density of OX42-ir cells between 3rd and 7th (81.86 vs. 129.99) (95% CI: −77.99 to −18.25, P = 0.0035) and between 14th and 21st (105.36 vs. 63.81) (95% CI: 13.21 to 69.89, P = 0.006) survival days were observed. However, significant increase of percentage of amoeboid OX42-ir cells between 3rd and 7th (0.98 vs. 48.71) (95% CI: −52.17 to −43.30, P = 0.0001) and between 7th and 14th (48.71 vs. 58.47) (95% CI: −13.96 to −5.55, P = 0.0002) and then their decrease – between 14th and 21st (58.47 vs. 31.74) (95% CI: 22.52 to 30.93, P = 0.0001) days of observation were noted. In the sevoflurane groups OX42-ir cells were not found. On the 3rd day the density of OX6-ir cells in the sevoflurane group was significantly lower than that in the control group (12.39 vs. 34.57) (95% CI: −49.78 to −2.96, P = 0.02). The percentage of an amoeboid form of OX6-ir cells was significantly lower in the sevoflurane group than that in the control group (27.31 vs. 82.03) (95% CI: −72.52 to −36.92, P = 0.0001) (58.76 vs. 82.37) (95% CI: −38.81 to −8.41, P = 0.003) (42.87 vs. 81.55) (95% CI: −53.23 to −24.10, P = 0.0001) respectively for 3rd, 7th and 14th days of survival. Conclusion: Administration of sevoflurane during anaesthesia in animals with intracerebral haemorrhage evoked a decrease of activation of the microglial cells.

Summary

Background and objective: Recently published guidelines for checking anaesthetic equipment do not contain specific advice on how to check the correct functioning of the capnograph before inducing anaesthesia. Methods: We undertook a postal survey of UK consultant (physician) anaesthetists to establish what methods for checking the capnograph are currently in use. Two hundred and two questionnaires were sent to consultants in different hospitals and 163 returned, a response rate of 81%. Results: 52.1% consultants of check the capnograph themselves. Of these, 55.3% use their own expired breath to confirm a response to carbon dioxide. Other methods used by consultant anaesthetists to check capnograph function include the machine self-test (16.5%), visual checks of the capnograph and sampling tubing (10.3%), and sampling of patient expired carbon dioxide (7.1%). Conclusion: The most common method for testing capnograph function among consultant anaesthetists and their assistants in the UK is the direct measurement of exhaled breath.

Summary

Background and objective: Although an epidural autologous blood patch is considered the most effective treatment for post dural puncture headache, which sometimes occurs following spinal or inadvertent spinal anaesthesia, there remains a need for alternative materials for epidural patches. We investigated the potential neurotoxicity of Dextran 40 (Rheomacrodex) and Polygeline (Haemaccel) used for this purpose in a rat model. Methods: Repeated boluses of 10% Dextran 40, 3.5% Polygeline or 0.9% saline were injected intrathecally over a period of 1 month in three groups of rats. Results: No behavioural or clinical derangements were observed in any of the three groups during this period. After sacrifice of the animals at the end of the experiment, no significant differences in the histopathological appearances of the spinal cords in the three groups were observed. No toxic effects diminishing viability of spinal cord cells were evident. Similarly, viability of renal, hepatic and peripheral blood mononuclear cells remained unaffected (98% ± 2%). Conclusions: No deleterious effects, clinical or cellular, were evident in this rat model when Dextran 40 or Polygeline were injected intrathecally. Thus, both substances can be considered as possible alternative materials for epidural patches.

Summary

Background and objective: Computerized dynamic posturography using an intentional postural-sway task can be used to assess body-leaning ability and postural-control ability to prevent falls. Falls are the leading cause of morbidity and mortality for the elderly. The purpose of the present study was to evaluate the recovery of intentional dynamic balance function after intravenous sedation with midazolam in elderly subjects in comparison with that in young subjects. Methods: Midazolam was administered in small, divided doses over 4–5 min until the Wilson sedation score reached three in 20 young and 18 elderly male volunteers. The dynamic limits of the stability test, in which subjects leaned their body intentionally as indicated by a cursor moving on a computer screen, was determined before (baseline) and 50, 70, 90, 110, and 130 min after administration of midazolam. Results: The changes from baseline values of path sway and movement time 50 min after the administration of midazolam in elderly subjects (106.8 ± 101.0%, 4.6 ± 3.0 s; mean ± SD) were significantly greater than those (32.9 ± 87.2%, 1.9 ± 2.8 s) in young subjects (P = 0.024, P = 0.008), respectively. Conclusions: The elderly show slower recovery of the intentional dynamic balance function than do young adults after intravenous sedation with midazolam.

Summary

Background and objective: Following the discovery of the feasibility of assessing the adequacy of the splanchnic perfusion by means of gastrotonometry, this technique became extensively used in clinical practice and in research. At present, high-technology instruments are available for the purpose. However, there is still a need for a simple, cheap tool that is easily applicable for patients of all ages. The present article describes such a tool and presents the results of in vitro and in vivo validation measurements with it. Methods: Balloon-free tonometric probes consisting of silicone rubber tubes were developed. In vitro measurements of the uptake of CO2 inside the probes and for comparison in a conventional ballooned intestinal tonometer were made in a closed container maintained at 37°C. In in vivo studies in anaesthetized dogs, the tonometric PCO2 values were determined with a tonometric probe and catheter introduced simultaneously into the ileum of the animals and the results were analysed by the Bland–Altman method. Results: The in vitro equilibration studies revealed that the filling media inside the probes equilibrated rapidly with the PCO2 content of the chamber. The data obtained from the in vivo investigations with the two different methods demonstrated a statistically significant linear association (correlation coefficient: 0.778, significance: P < 0.001). Conclusion: The new simple tonometric probe described appears to be a reliable tool with certain advantages for gastric tonometry. However, further studies are warranted before its general clinical use.

Summary

Background and objective: Every member of healthcare personnel should be able to perform basic life support including defibrillation (CPR-D). The biggest cost of implementation is training and these costs need to be reduced. The purpose of this randomized study was to evaluate the applicability of distance learning as a method to teach CPR-D. Methods: Nurses (n = 56) working in a geriatric hospital were randomized into three groups. The first group was given the Internet-based CPR-D course and the second was given a traditional, small-group CPR-D course. A third group without specific training in CPR-D served as a control group. An objective structured clinical examination (OSCE) was performed 2 weeks after the courses with a manikin patient having a cardiac arrest. Results: The median score of all participants was 31/49 (range 21–38). The reliability of the checklist was adequate (Cronbach alpha 0.77). Nurses receiving traditional CPR-D performed better than those receiving the Internet-based course (median score 34 vs. 28, P < 0.05) and the control group (median score 34 vs. 26, P < 0.0001). Nurses receiving Internet-based course performed similarly as the control group (median score 28 vs. 26, ns). Conclusions: Distance learning cannot substitute for traditional small-group learning.

Summary

Background and objectives: The potential for increased drug administration errors during the transition to the International Colour Coding syringe labelling system has been highlighted. The purpose of this study was to assess the potential effects before their introduction into our department. Methods: Thirty-one anaesthetists, 19 with no previous practical experience of the new labelling system (Group 1), and 12 with previous experience (Group 2), volunteered to induce general anaesthesia for a standardized simulated patient in a designated theatre. They were presented with a scenario designed to suggest the need for a rapid sequence induction and provided with drug syringes labelled with the International Colour Coding system. All drug administrations were recorded. Active error was defined as the injection of the wrong drug. Latent error was defined as the selection of a syringe in error but stopping short of administering the drug. Results: In Group 1 a total of 107 drug injections were recorded of which 1 (0.9%) was an active error and 16 (15%) involved latent errors. Eleven anaesthetists (58%) performed at least one latent error. Group 2 had an error rate of 3%, a 6.9 (1.3–26.7) fold reduction in the rate of error (P = 0.023). Conclusions: Although only one drug was given in active error, latent errors occurred in 15% of drug administrations. The only factor conferring protection against error was prior experience of the new labelling system. The period of transition to the International Colour Coding syringe labelling system represents a time of increased risk of drug administration error.

Summary

Background and objective: We have compared the effects of gabapentin on arterial pressure and heart rate at induction of anaesthesia and tracheal intubation in a randomized double-blind study. Methods: Ninety normotensive patients (ASA I) undergoing elective surgery were divided into three groups of 30 patients each. Patients received oral placebo (Group I), 400 mg of gabapentin (Group II) or 800 mg of gabapentin (Group III) 1 h prior to surgery in the operating theatre. After induction of anaesthesia heart rate and mean arterial pressure were recorded at baseline 1, 3, 5, 10 and 15 min after intubation. Results: Patients receiving placebo and 400 mg gabapentin showed a significant increase in blood pressure and heart rate associated with tracheal intubation compared to baseline levels and Group III. There was significant decrease in heart rate and arterial pressure in Group III after intubation 1, 3, 5 and 10 min (P < 0.001, P < 0.001, P < 0.05 and P < 0.05, respectively) compared to Groups I and II. Conclusion: Given 1 h before operation gabapentin 800 mg blunted the arterial pressure and heart rate increase in first 10 min due to endotracheal intubation. Oral administration of gabapentin 800 mg before induction of anaesthesia is a simple and practical method for attenuating pressor response to laryngoscopy and tracheal intubation after standard elective induction.

Summary

Background and objective: Out-of-hospital intravenous line placement is used daily. All available studies take place using paramedics, e.g. US-American emergency medical system. The aim of this study was to assess the intravenous line placement feasibility (time and success rate) in the French emergency medical system. Methods: A prospective observational study was performed by a French out-of-hospital team during 3-month assessing the timing and success rates for intravenous line placement. All patients were enrolled at the emergency medical service of a university hospital in France. Six hundred and sixty-nine consecutive patients were included, 388 (58%) had at least one intravenous line placement in the out-of-hospital setting. Results: Success rate was 76% at the first attempt and 98% at the second attempt. The overall success rate for intravenous line placement was 99.7% (only one failure), and the average successful intravenous line time was 4.4 ± 2.8 min. Attempts ranged from 1 to 8. The time for intravenous line placement with blood sampling (58% of patients) is statistically longer than without (4.6 ± 2.5 vs. 4.3 ± 3 min, P < 0.05). Seventeen of the enrolled patients were trauma patients, and 83% were non-trauma patients. Four hundred and twenty-seven intravenous lines were placed, intravenous 10% had more than one intravenous line. Seventy-one percent of the intravenous lines were used to infuse drugs, the others were security intravenous. No significant difference was noticed between trauma and non-trauma patients in regard to the success rate and the time to place the intravenous line. Conclusion: The out-of-hospital team was skilled at intravenous line placement (success rate = 99.7%), and the time required to performed intravenous line access was short.

Summary

Background and objective: Anaesthesia information management systems, though still not used widely, will inevitably replace handwritten records and may eventually serve as a core for the development of computerized decision support. We investigated staff expectations and the accuracy of data entry in a recently implemented commercially available anaesthesia information management system. Methods: A structured questionnaire was administered to the staff before and 1 week and 3 months after implementation in order to assess their opinion. The quality of manual data entry, and of automatic data record was evaluated by looking for missing data and the prevalence of artefacts. Results: Despite initial fears the users quickly accepted the system. Both automatic and manual data entry were found to be accurate and reliable while the prevalence of artefacts was relatively low. Conclusions: A commercially available anaesthesia information management system can be easily implemented and used instead of paper charts.

Summary

Background and objective: We have investigated the accuracy of the Colin tonometry module, a non-invasive alternative to intra-arterial blood pressure (BP) measurement. The claims of previous publications range between good agreement to significant discrepancies between the Colin tonometry and intra-arterial methods. The Colin method relies on calibration of the tonometry module using an oscillometric method. Our aim was to look at the effect of this calibration on the accuracy. Methods: Ten conscious patients who already had an indwelling arterial catheter were studied. The Colin monitor was set to perform ten calibration cycles first with the oscillometric cuff on the same arm as the tonometry module and secondly on the opposite arm. Simultaneous recording of BP wave forms from the intra-arterial BP transducer and the Colin monitor allowed comparison of beat-by-beat systolic, diastolic and mean BP. Results: There was considerable inter- and intra-patient variation. In the worst case, the error range was 41 mmHg over ten calibrations. Analysis of variance showed that contra- and ipsilateral calibrations gave a significantly different bias while the multiple calibrations accounted for a significant proportion of the variability in systolic BP error. Conclusions: The Colin Tonometry method is not accurate enough to be used with confidence in clinical practice. The main reason for this is its reliance on an oscillometric method for calibration of the tonometry module. Single BP measurements, using either manual or semiautomatic instruments may vary considerably from the ‘true’ BP due to short-term perturbations of BP.

Summary

Background and objective: Arterial grafts are prone to vasospasm. Opioid analgesics are commonly used in the perioperative course of cardiac surgical procedures. Therefore, we investigated the direct effects of morphine, meperidine, fentanyl and remifentanil on the human radial artery. Methods: Radial artery segments, obtained from 20 patients, were precontracted with phenylephrine. Using the organ bath technique, the endothelium-independent vasodilatation was tested in vitro by addition of cumulative concentrations of morphine, meperidine, fentanyl and remifentanil in separate organ baths, in the presence or absence of naloxone. Indomethacin and NG-nitro-l-arginine methyl ester was added to all organ bath in order to determine the effects of prostaglandins and nitric oxide, respectively. Results: Morphine (10−8–10−4mol L−1), meperidine (10−10–10−6mol L−1), fentanyl (10−10–10−6mol L−1) and remifentanil (10−8–10−4mol L−1) caused a concentration-dependent vasorelaxation in the human being artery rings. The relaxations in the presence of naloxane did not change. The maximal relaxant effects of meperidine and fentanyl were significantly greater than those of morphine and remifentanil (P < 0.05). Conclusions: These findings indicate that morphine, meperidine, fentanyl and remifentanil produce concentration-dependent and endothelium-independent relaxations in human being radial artery rings. Meperidine and fentanyl are more potent relaxant agents than morphine and remifentanil in the human being radial artery in vitro.

Summary

Background and objective: Proinflammatory cytokines as well as nitric oxide (NO) play a major role in mediating the response to lipopolysaccharide (LPS). The present study tested the hypothesis that LPS induces proinflammatory cytokines in the lung via the Toll-like receptor 4 (TLR4)/CD14 signalling cascade. Methods: Control mice and TLR4-deficient (TLR4-D) mice were used to test TLR4-mediated effects of LPS. Both strains received either Escherichia coli LPS (20 mg kg−1 intraperitoneal) or saline and their lungs were collected at different time points. Pulmonary nuclear factor κB (NFκB) activation was investigated with electromobility shift assay. mRNA expression of inflammatory mediators and their corresponding receptors were detected with Ribonuclease Protection Assay. Protein expression was detected by ELISA and western blotting. Inducible NO synthase (iNOS) expression was monitored by RT-PCR and iNOS activity by conversion of l-arginine to citrulline. Immune cells were sampled by bronchoalveolar lavage (BAL) and classified. Results: LPS application induced CD14-, but not TLR4 protein expression in control mice. Activation of pulmonary NFκB was observed within 60 min in control, but not in TLR4-D mice. Six hours of LPS administration induced a significant increase in pulmonary tumour necrosis factor α-, interleukin-1β- and interleukin-6 mRNA and protein expression in control mice compared to TLR4-D mice. Furthermore, LPS induced a significantly higher increase of the iNOS expression and catalytic activity in control mice than in TLR4-D mice. BAL revealed an increase in total cell count in all LPS treated mice. Conclusion: Our findings suggest that TLR4 plays a key role for regulating the expression of relevant cytokines within the lung during endotoxic shock.

Summary

Background and objectives: Preoperative evaluation performed by anaesthesiologists primarily aims to estimate the risk of perioperative complications and to create opportunities to optimize the patients' condition before surgery. In this study an inventory was made of the current practice of preoperative evaluation in Dutch hospitals. It was estimated how many hospitals had implemented an outpatient preoperative evaluation clinic in 2004. Subsequently, current practice was compared with the results of a previous inventory (2000). It was also evaluated to what extent the guidelines of the Dutch Health Council and the Netherlands Society of Anaesthesiology were followed. Methods: The study consisted of two phases. First, a literature research was performed and pilot interviews were constructed. The interviews were conducted face-to-face with anaesthesiologists in a sample of Dutch hospitals. Based on the results, written questionnaires were constructed. In the second phase these questionnaires were sent to all general and academic hospitals in the Netherlands. Results: In 2004, 74% of the hospitals had an outpatient preoperative evaluation clinic, compared with 50% in 2000. The percentage of hospitals with an outpatient preoperative evaluation clinic available for all elective patients increased from 20% to 52%. Conclusions: The Dutch guidelines on preoperative evaluation seem to have influenced current practice. An increase in the number of outpatient preoperative evaluation clinics was seen after the guidelines were published. The implementation of an outpatient preoperative clinic seems to warrant that anaesthesiologists are carrying out the activities prescribed by the guidelines. Most hospitals without a clinic aim to implement one in the future.

Summary

Background and objective: Magnesium administered before anaesthesia induction results in a significant reduction in intravenous anaesthetic consumption. The purpose of this study was to evaluate whether the dose of intravenous magnesium sulphate reduces the minimum alveolar anaesthetic concentration of sevoflurane for endotracheal intubation (MACEI) and skin incision (MAC), and attenuates haemodynamic responses. Methods: We studied 60 patients who were scheduled for elective surgery. Patients were not premedicated before induction of anaesthesia and were randomly assigned to receive intravenous saline 0.9% (Group I, n = 20) or magnesium sulphate 30 mg kg−1 bolus + 10 mg kg−1 h−1 continuous infusion (Group II, n = 20) or 50 mg kg−1 bolus + 10 mg kg−1 h−1 continuous infusion (Group III, n = 20). Results: Median and 95% confidence limits for sevoflurane MACEI were 2.68 (2.48–2.85), 2.88 (2.70–3.06) and 2.96 (2.70–3.16), and for sevoflurane MAC were 2.08 (1.76–2.40), 2.26 (2.08–2.47) and 2.40 (2.19–2.68) in Groups I, II and III, respectively. The differences in MACEI and MAC among groups were not statistically significant, except Group III in MAC study (P < 0.05). Mean arterial pressures and heart rate did not increase in Groups II and III after endotracheal intubation and skin incision. Conclusions: Magnesium sulphate administered before induction of anaesthesia increases MAC of sevoflurane and reduces cardiovascular responses to intubation.