Showing papers in "BJA: British Journal of Anaesthesia in 1993"

Re-expansion of atelectasis during general anaesthesia: a computed tomography study

Abstract: Formation of atelectasis is one mechanism of impaired gas exchange during general anaesthesia. We have studied manoeuvres to re-expand such atelectasis in 16 consecutive, anaesthetized adults with healthy lungs. In group 1 (10 patients), the lungs were inflated stepwise to an airway pressure (Paw) of 10, 20, 30 and 40 cm H2O. In group 2 (six patients), three repeated inflations up to Paw = 30 cm H2O were followed by one inflation to 40 cm H2O. Atelectasis was assessed by analysis of computed x-ray tomography (CT). In group 1 the mean area of atelectasis in the CT scan at the level of the right diaphragm was 6.4 cm2 at Paw = 0 cm H2O, 5.9 cm2 at 20 cm H2O, 3.5 cm2 at 30 cm H2O and 0.8 cm2 at 40 cm H2O. A Paw of 20 cm H2O corresponds approximately to inflation with twice the tidal volume. In group 2 the mean area of atelectasis was 9.0 cm2 at Paw = 0 cm H2O and 4.2 cm2 after the first inflation to 30 cm H2O. Repeated inflations did not add to re-expansion of atelectasis. The final inflation (Paw = 40 cm H2O) virtually eliminated the atelectasis. We conclude that, after induction of anaesthesia, the amount of atelectasis was not reduced by inflation of the lungs with a conventional tidal volume or with a double tidal volume ("sigg"). An inflation to vital capacity (Paw = 40 cm H2O), however, re-expanded virtually all atelectatic lung tissue.

The value of pre-emptive analgesia in the treatment of postoperative pain

Abstract: Our knowledge and understanding of the physiology of acute pain has improved in recent years. Most of this new information has been gathered from basic science and experimental studies. The recent papers by Wall [40] and Woolf [41] have stimulated much discussion on the potential clinical implications of this knowledge for the management of acute postoperative pain, and the concept of \"pre-emptive analgesia\" has gained widespread acceptance. This paper is a critical analysis of clinical studies on the effects of pre-emptive analgesia on acute postoperative pain.

Perioperative management of the obese patient

Abstract: Obesity is a metabolic disease in which adipose tissue comprises a greater proportion of body tissue than normal. It affects up to 33 % of the population in North America [11, 112]. Almost 5% weigh more than double their ideal body weight as predicted by age, sex and height. The precursors to obesity are multifactorial and include a genetic tendency, environmental effects, education, sex, race and socio-economical status [83]. Most of die major obesity-related health risks increase disproportionately with increasing weight. The rate of premature death is increased in patients 30% overweight and doubles in populations weighing 40-60 % more than ideal body weight [29,47,73]. The incidence of sudden unexplained death is at least 13 times greater in morbidly obese women compared with non-obese ones [73]. In men participating in the Framingham study, being overweight was found to be associated with a mortality rate of up to 3.9 times greater than the normal-weight group. An increased rate of chronic diseases, many life threatening, has been found in prospective studies of obese patients [46, 118]. These include peripheral vascular disease, cardiorespiratory derangements, liver disease, diabetes mellitus, polycythaemia, hyperlipoproteinaemia, diaphragmatic hiatus hernia and malignancies [22,26,42,46,68,73,112,115]. Nevertheless,weight reduction immediately before surgery has not been shown to reduce perioperative morbidity or mortality, even though it may reverse some of the pathophysiological changes in the obese patient [5-7, 67, 102, 104]. In this review we discuss the pathophysiological changes in the obese patient and their effects in the periods before, during and after operation. The anaesthetist managing an obese patient should be familiar with the special difficulties expected, and plan management accordingly [26, 29].

Use of ultrasound to evaluate internal jugular vein anatomy and to facilitate central venous cannulation in paediatric patients

Abstract: Percutaneous cannulation of the internal jugular vein in paediatric patients may be technically difficult and is prone to complications. To investigate the possibility that anatomical factors contribute to these difficulties, we used a two-dimensional ultrasound scanner to examine venous anatomy in children aged up to 6 yr. We found that 18% of our children had anomalous venous anatomy that may account for some of the difficulties reported previously. The diameter of the internal jugular vein was predicted poorly by the patient's age (r2= 0.259) or weight (x2 = 0.155). We also evaluated the use of this ultrasound scanner during percutaneous central venous cannulation in neonates and infants. Determining the course of the internal jugular vein with the scanner and then marking it on the overlying skin reduced both the time and number of needle insertions required to aspirate jugular venous blood and increased the chance of a complication-free cannulation. (Br. J. Anaesth. 1993; 70: 145–148)

Logistic regression analysis of fixed patient factors for postoperative sickness: a model for risk assessment

Abstract: One hundred and forty-seven patients undergoing minor orthopaedic surgery were studied prospectively by logistic regression analysis to determine the association of independent fixed patient factors with the incidence of postoperative sickness (nausea, retching or vomiting). Gender, history of previous postoperative sickness, postoperative opioids and interaction between gender and previous history of sickness were significant independent factors for postoperative sickness; history of motion sickness was weakly associated. The probability of postoperative sickness in the first 24 h after surgery may be estimated from the equation: logit postoperative sickness = -5.03+2.24(postoperative opioids) +3.97 (previous sickness history) +2.4 (gender) +0.78 (motion sickness) -3.2 (gender x previous sickness history). (Log likelihood ratio test for 5 degrees of freedom for the coefficients, chi-square = 53.5 (P < 0.001).) It is suggested that the calculated probability for sickness may be a useful addition for balancing patient treatment groups and allowing between-study comparisons.

Problems associated with tracheal extubation

Abstract: All anaesthetists will, at some stage, have experienced problems after tracheal extubation. Indeed, the frequency of such problems probably exceeds those relating to tracheal intubation. Whereas a large volume of the anaesthetic literature addresses problems associated with tracheal intubation, it is unusual to find discussion concerning those following extubation. This review attempts to redress this imbalance.

Magnetic resonance imaging of extradural blood patches: appearances from 30 min to 18 h

Abstract: We have used magnetic resonance imaging to examine five patients treated with extradural blood patches for persistent post lumbar puncture headache. Images were obtained between 30 min and 18 h after patching. Extradural blood patch injection produced a focal haematoma mass around the injection site which initially compressed the thecal sac and nerve roots. The main bulk of the extradural clot extended only three to five spinal segments from the injection site, although small amounts of blood spread more distally. Spread from the injection site was principally cephalad. Mass effect was present at 30 min and 3 h, but clot resolution had occurred by 7 h, leaving a thick layer of mature clot over the dorsal part of the thecal sac. Eighteen hours after injection only small widely distributed clots, adherent to the thecal sac, were demonstrated. Extensive leakage of blood from the injection site into the subcutaneous tissues was present in all patients.

Comparison of the reinforced laryngeal mask airway and tracheal intubation for adenotonsillectomy

Abstract: One-hundred and four patients were allocated randomly to receive anaesthesia for adenotonsillectomy via either a reinforced laryngeal mask airway or tracheal tube. Airway maintenance and protection were assessed during and after operation. The reinforced laryngeal mask did not interfere with surgical access; it resisted compression and protected the lower airway from contamination with blood. Four patients were withdrawn from the laryngeal mask airway group: two because difficulty with placement, and two because the laryngeal mask was obstructed distally when the Boyle Davis gag was opened fully. In children, recovery was less eventful in the laryngeal mask airway group, with less airway obstruction (P < 0.001) and better airway acceptance (P < 0.05). The reinforced laryngeal mask airway provided a clear, secure airway until recovery of protective reflexes.

Preoperative drinking does not affect gastric contents

Abstract: We have compared the effect of allowing free clear fluids until the time of oral premedication with conventional preoperative fasting. In a prospective, randomized trial, the residual volume and pH of gastric contents after induction of anaesthesia were measured in 100 elective surgical patients allocated randomly to a group in whom the intake of free clear fluids up to the time of premedication was measured (mean 388 ml in 6 h before surgery) or a control group who were fasted for 6 h. Preoperative drinking did not affect either mean (SD) residual gastric volume (22 (21) ml in the study group vs 19 (16) ml in the control group) or pH (study group 2.64 (1.57) vs control group 2.26 (1.45)). The study group experienced less preoperative thirst. Problems with aspiration or regurgitation were not encountered. We believe that allowing elective surgical patients to drink clear fluids until 2 h before anaesthesia may enhance patient comfort without compromising safety.

Prevention and treatment of hypotension during central neural block

Abstract: Hypotension during central neural block may occur by three main mechanisms: decrease in venous return (in turn influenced by posture, bleeding and inferior vena cava compression), vasodilatation and decreased cardiac output. It is also important to recognize that, occasionally, other factors play a part. Bladder distension during central nerve block has been shown to produce hypotension inappropriate to the level of block [48, 62] and vagal overactivity may contribute in the unsedated patient. Preventive measures to reduce the likelihood of hypotension include correction of hypovolaemia, restriction of the upper level of block, use of a slight head-down tilt to maintain venous return and judicious use of sedation, especially in anxious patients. In the obstetric patient, the single most important factor in eliminating hypotension is the use of full left-lateral tilt. Mechanical methods to improve venous return by compressing the legs are not particularly helpful. Volume loading does not guarantee maintenance of arterial pressure and excessive fluid may be harmful in patients with bladder neck obstruction or at risk of pulmonary oedema. The administration of up to 1 litre before surgery may be particularly advisable if significant blood loss is expected (no matter what the anaesthetic technique), but colloid solutions do not have clear proven benefit over crystalloid. The prevention or treatment of hypotension induced by central block by administration of large volumes of fluid is a more contentious subject, although the practice is widespread. Review of the literature has shown that many studies have been poorly designed and the results have often been contradictory, even in such basic principles as the incidence of hypotension in control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A new method of measuring cardiac output in man using lithium dilution

Abstract: We describe a new indicator dilution method of measuring cardiac output in man. A bolus injection of lithium chloride 0.6 mmol was given via a central venous catheter and arterial plasma [Li + ] recorded using a specially developed sensor incorporating an Li + -selective electrode. Cardiac output was derived from the lithium dilution curve, with a correction for packed cell volume. Lithium dilution cardiac output (LiDCO) was compared with thermodilution cardiac output (TD) using 22 lithium sensors in nine patients. For each sensor, one LiDCO was measured immediately before and one immediately after three TD estimations and mean values of LiDCO and TD derived. The correlation coefficient, r , was 0.89; slope of the regression 0.84; Y intercept 0.72; bias 0.3 (0.5) litre min −1 (mean (TD-LiDCO) (1 SD). LiDCO appeared to be a safe, simple and accurate technique which does not require insertion of a pulmonary artery catheter.

Transoesophageal echocardiographic assessment of haemodynamic function during laparoscopic cholecystectomy

Abstract: We have measured cardiovascular changes associated with insufflation of carbon dioxide and the reverse Trendelenburg position during laparoscopic cholecystectomy, using transoesophageal echocardiography in 13 healthy patients. End-tidal carbon dioxide values increased after insufflation of carbon dioxide, with values significantly (P < 0.05) increased after lateral tilt positioning. Creation of a pneumoperitoneum was associated with increases (P < 0.05) in left ventricular end-systolic wall stress, concomitant with increases (P < 0.01) in peak airway pressure and systemic arterial pressure. In addition, left ventricular end-diastolic area decreased (P < 0.05) after reverse Trendelenburg positioning. Left ventricular ejection fraction was maintained throughout the study.

Pharmacokinetics and pharmacodynamics of ketamine enantiomers in surgical patients using a stereoselective analytical method

Abstract: In a randomized, double-blind study, we have examined the stereoselective disposition and pharmacodynamic characteristics of ketamine in surgical patients after i.v. administration of S(+)-ketamine 1 mg/kg body weight (25 patients) or racemic ketamine 2 mg/kg body weight (25 patients). S(+)-Ketamine was not inverted to R(-)-ketamine. After racemate administration we observed statistically significant (P < 0.01) smaller clearance and volume of distribution for R(-)-ketamine compared with S(+)-ketamine. In contrast, the pharmacokinetic variables of S(+)-ketamine were not significantly different between treatment groups. Systolic and diastolic arterial pressure and heart rate increased significantly (P < 0.005) in both groups. At 1, 3 and 15 min after S(+)-ketamine administration, significantly greater increase in systolic and diastolic pressures were observed compared with the racemate group. There was no correlation between the changes in haemodynamic variables and plasma catecholamine concentrations, which remained unaffected after administration of the medications.

Pressure exerted by the laryngeal mask airway cuff upon the pharyngeal mucosa

Abstract: SUMMARY Ten patients were studied for each of the sizes 2, 3 and 4 laryngeal mask airways (LMA) in order to calculate the pressure exerted by the cuff upon the pharyngeal mucosa. Using a non-invasive method of comparing intracuff pressures recorded both in vitro and in vivo, the transmitted pharyngeal mucosal pressures were calculated over the clinical range of injection volumes. Cuff inflation with the “normal” injection volumes recommended resulted in the residual volumes of the cuffs being exceeded. The intracuff pressures recorded with the mask in situ at these normal injection volumes were in the range 103-251 mm Hg. The calculated transmitted mucosal pressures were substantial for all three sizes of cuff and potentially exceeded the capillary perfusion pressure of the adjacent pharyngeal mucosa, despite apparent pharyngeal accommodation to the mask. (Br. J. Anaesth. 1993; 70: 25–29)

Excitatory and inhibitory synaptic mechanisms in anaesthesia

Abstract: To understand the cellular and molecular basis of the anaesthetic state, it is important to remember that, in the intact CNS, synapses operate within elaborate nerve networks. From the data presented above, it is evident that block of impulse conduction in presynaptic fibres does not explain the effects of most anesthetics on synaptic activity. This is not surprising since some anaesthetics, the barbiturates in particular, may both depress excitation and enhance inhibition. General anaesthetics modulate the activity of presynaptic voltage-gated calcium channels and this appears to be sufficient to account for the reduction in transmitter secretion they produce. Transmitter operated ion channels in the postsynaptic membrane are modulated by smaller concentrations of anaesthetics than are required to modulate the presynaptic voltage-gated calcium channels. For this reason, transmitter operated channels appear to represent a major target site for anaesthetics. Finally, there are subtle effects of anaesthetics on the patterns of impulse propagation in nerve axons and on action potential generation in the cell body which result from modulation of membrane excitability. The overall effect of an anaesthetic agent depends on summation of events occurring at the many individual synapses and neurones that make up the network. The effects of anaesthetics on different neuronal pathways may therefore depend on the nature of the receptors and ion channels of the cells that comprise the network. The anaesthetic state may be the result of all these actions, but the characteristics of the state may differ somewhat from agent to agent.

Blood loss during repair of craniosynostosis

Abstract: Surgical repair of craniosynostosis carries a high risk with large blood losses. Over a 2-yr period, we have managed 115 patients undergoing cranio synostosis repair with peroperative haemodllution to achieve a final PCV of 0.28–0.35. Measurements of PCV allowed calculation of estimated blood losses and transfused volumes in terms of red blood cell mass. Total estimated red cell volume lost was 91±66+ of patient's estimated red blood cell volume during the peroperative period. The type of skull deformation and surgical procedure deter mined the extent of peroperative bleeding. Peroperative transfusion was satisfactory in 48% of patients and slight overtransfusion was noted in 32%. During the postoperative period, liberal administration of blood led to overtransfusion and possibly unnecessary transfusion in 74% of patients. Because of the well known risks of transmission of infectious disease, strict volume compensation with development of haemodilution and autotransfusion procedures should be used to limit these risks. (Br. J. Anaesth. 1993; 71 : 854–857)

Effect of extradural analgesia on stress responses to abdominal surgery in infant

Abstract: SUMMARY We studied 40 children younger than 4 yr having elective abdominal surgery under general anaesthesia supplemented with either systemic opioids or extradural bupivacaine. Venous blood samples were obtained before tracheal intubation to measure baseline concentrations of adrenaline, noradrena-line, glucose, ACTH and cortisol. Additional samples were obtained 45 min after the start of surgery, at the end of surgery, 1 h and 24 h after the end of surgery. Plasma concentrations of bupivacaine were measured also in the extradural group at each sampling time. Both techniques provided acceptable analgesia, but the perioperative increases in adrenaline, glucose and ACTH were significantly greater in the opioid group. Nor-adrenaline concentrations decreased to less than baseline values in the extradural group and were significantly less than in the opioid group. The perioperative increase in cortisol was similar in the two groups, despite the differences in ACTH responses. Most responses returned to the baseline values within 24 h. Plasma bupivacaine concentrations remained within safe limits during the study, but systemic concentrations increased in some of the patients during postoperative infusion with 0.125% bupivacaine. (Br. J. Anaesth. 1993; 70: 654–660)

Comparison of patient-controlled analgesia with and without a background infusion after lower abdominal surgery in children

Abstract: Forty children aged 6–12 yr undergoing appendicectomy were allocated randomly to receive postoperative i.v. morphine by a patient-controlled analgesia (PCA) system (bolus dose 20 μg kg −1 with a lockout interval of 5 min) or the same PCA with a background infusion of morphine 20 μg kg −1 h −1 Patients breathed air and oxygen saturation was monitored by continuous pulse oximetry. Scores for pain, sedation and nausea were recorded hourly. Patients with PCA + background infusion received significantly more morphine than those with PCA only. Both groups selfadministered similar amounts of morphine using the PCA machine. There were no significant differences in the pain scores of the two groups. Patients with PCA + background infusion suffered more nausea (P 71 : 670–673).

Mandibulohyoid distance in difficult laryngoscopy

Abstract: We studied radiographically 11 patients in whom direct laryngoscopy proved difficult and 100 control (general population) subjects. The vertical distance between the mandible and the hyoid bone (mandibulohyoid distance) was measured and the positions of the mandibular angle and hyoid bone determined in relation to the cervical vertebrae. We found that the mandibulohyoid distance was substantially longer in patients whose trachea was difficult to intubate; the mandibular angle tended to be positioned more rostrally in both men and women, and the hyoid bone tended to be positioned more caudally in women. This suggests that a relatively short mandibular ramus or a relatively caudal larynx may be important, unfavourable anatomic factors in difficult laryngoscopy.

Midazolam–alfentanil: an anaesthetic? an investigation using the isolated forearm technique

Abstract: SUMMARY Thirty-two women underwent major gynaecological surgery with a midazolam-alfentanil total i.v. anaesthetic regimen. Adequacy of anaesthesia was assessed using a "pressure, rate, sweating and tears" (PRST) scoring system in conjunction with the isolated forearm technique (IFT). The IFT revealed that 72% of patients responded during surgery, but none had spontaneous, unprompted postoperative recall for the event. Three patients, on prompting, provided evidence of recall. The IFT, while indicating which patients are responsive, cannot be used to predict who will have postoperative recall. Lack of explicit postoperative recall does not indicate unconsciousness during surgery. Twenty patients, asked specifically during surgery to indicate the presence or absence of pain, experienced pain at some time during their surgical procedure. The PRST score could not be used to predict when a patient was awake. This low-dose i. v. anaesthetic technique cannot be recommended for general use. (Br. J. Anaesth. 1993; 70 : 42–46)

Plasma concentrations of midazolam after i.v., nasal or rectal administration in children

Abstract: Midazolam is used frequently for premedication in children, preferably by non-parenteral administration. We have compared plasma concentrations of midazolam after nasal, rectal and i.v. administration in 45 children (aged 2-9 yr; weight 10-30 kg) undergoing minor urological surgery. General anaesthesia consisted of spontaneous respiration of halothane and nitrous oxide in oxygen via a face mask. After administration of atropine and fentanyl i.v., children were allocated randomly to receive midazolam 0.2 mg kg-1 by the nasal, rectal or i.v. route. In the nasal group, children received 50% of the dose of midazolam in each nostril. In the rectal group, midazolam was given rectally via a cannula. Venous blood samples were obtained before and up to 360 min after administration of the drug. Plasma concentrations of midazolam were measured by gas chromatography and electron capture detection. After nasal and rectal administration, midazolam Cmax was 182 (SD 57) ng ml-1 within 12.6 (5.9) min, and 48 (16) ng ml-1 within 12.1 (6.4) min, respectively. Rectal administration resulted in smaller plasma concentrations. In the nasal group, a plasma concentration of midazolam 100 ng ml-1 occurred at about 6 min. After 45 min, the concentration curves after i.v. and nasal midazolam were similar.

Comparison of midazolam with propofol for sedation in outpatient bronchoscopy

Abstract: We have compared sedation for fibreoptic bron-choscopy provided by incremental doses of midaz-olam with that provided by a computer-controlled infusion of propofol. These two methods were compared in terms of operator and patient acceptability, anxiolysis, effects on systolic arterial pressure and oxygen saturation. Tesis were made also of memory and motor reactions, before and 60 min after the end of the procedure. Acceptability to operators and patients was high in both groups. There were no significant differences between the groups in systemic arterial pressure or anxiolysis. Oxygen saturation decreased in both groups (propofol group median 83% (range 69–95%); midaz-olam group median 86% (range 77–95%) (ns). The median recovery time was 5 min (range 5–10 min) in the propofol group and 10 min (range 5–40 min) in the midazolam group (P

Actions of the hypnotic anaesthetic, dexmedetomidine, on noradrenaline release and cell firing in rat locus coeruleus slices

Abstract: We have examined the effects of the highly selective alpha 2-adrenoceptor agonist, dexmedetomidine, on noradrenaline release and cell firing in isolated, superfused slices of rat locus coeruleus. Dexmedetomidine decreased both noradrenaline release and cell firing rate in a concentration-dependent fashion, with an EC50 of 3.97 (SEM 0.97) x 10(-9) mol litre-1 for noradrenaline release and 0.92 (0.53) x 10(-9) mol litre-1 for unit activity. Both effects were reversed completely by the selective alpha 2 antagonist, atipamezole 10(-6) mol litre-1. These results suggest that cell firing and noradrenaline release are under alpha 2 receptor control and that dexmedetomidine potently stimulates these receptors. We conclude that these effects are consistent with the locus coeruleus being a major site of action of the hypnotic anaesthetic alpha 2 agonists.

Time course of neuromuscular effects and pharmacokinetics of rocuronium bromide (org 9426) during isoflurane anaesthesia in patients with and without renal failure

Abstract: We have studied the onset and duration of action and pharmacokinetics of rocuronium bromide (Org 9426) during anaesthesia with nitrous oxide, fentanyl and isoflurane after a single bolus dose of rocuronium 0.6 mg kg−1 in nine patients with chronic renal failure requiring regular haemodialysis, and in nine healthy control patients. Blood samples were collected over 390 min and concentrations of rocuronium and its putative metabolites measured using HPL C. Onset time for maximum block, duration of clinical relaxation (T125) and recovery index, were 61 (SD 25.0) s and 65 (16.4) s, 55 (26.9) min and 42 (9.3) min and 28 (12.3) min and 19 (8.8) min, respectively, for patients with and without renal failure. The time for TOF ratio to return spontaneously to 0.7 was 99 (41.1) min and 73 (24.2) min, respectively, in the two groups. None of these differences was significant. The pharmacokinetic data were best described by a three-exponential equation. There were significant differences between patients with and without renal failure in the rates of clearance (2.5 (1.1) ml kg−1 min−1 and 3.7(1.4) ml kg−1 min−1 respectively) and the mean residence times (97.1 (48.7) min and 58.3(9.6) min) (P

Tracheal intubation after induction of anaesthesia with profol, alfentanil and i.v. lignocaine

Abstract: We have assessed tracheal intubating conditions in 60 ASA I or II patients after induction of anaesthesia with propofol 2.5 mg kg-1 and alfentanil 10 or 20 micrograms kg-1 with or without i.v. lignocaine 1 mg kg-1. No neuromuscular blocking agents were administered. Patients were allocated randomly to four groups: group 1 = propofol-alfentanil 10 micrograms kg-1; group 2 = propofol-alfentanil 10 micrograms kg-1-lignocaine 1 mg kg-1; group 3 = propofol-alfentanil 20 micrograms kg-1; group 4 = propofol-alfentanil 20 micrograms kg-1-lignocaine 1 mg kg-1. Intubating conditions were assessed as acceptable or unacceptable on the basis of a scoring system dependent on ease of laryngoscopy, vocal cord position and coughing on insertion of the tracheal tube. Intubating conditions were acceptable in 20%, 73%, 73% and 93% of patients in groups 1-4, respectively. Intubating conditions were better and there was less coughing in the lignocaine group.

Antiemetic efficacy of prophylactic ondansetron in laparoscopic surgery: randomized, double-blind comparison with metoclopramide

Abstract: In a randomized, double-blind study, we have compared the prophylactic antiemetic efficacy of ondansetron with that of metoclopramide in 123 patients undergoing general anaesthesia for day-case gynaecological laparoscopic surgery. The patients received either i.v. ondansetron 4 mg or metoclopramide 10 mg immediately before a standard anaesthetic. The number of patients with no nausea or vomiting in the ondansteron group was 50 (82%) compared with 29 (47%) in the metoclopramide group (P < 0.001). In those patients with a previous history of postoperative nausea and vomiting, nausea was less severe in those receiving ondansetron compared with those receiving metoclopramide (P < 0.05). We conclude that preoperative prophylactic administration of i.v. ondansetron was superior to metoclopramide in preventing nausea and vomiting after general anaesthesia for day-case gynaecological laparoscopic surgery.