In recent years, day surgery rates have risen in many countries in the world. In 1998–99, 65% of elective surgery was performed as day procedures in the UK and about 70% in the USA. The future has the potential for an increase in day surgery as less well-performing countries and hospitals catch up with the best, and new surgical, anaesthetic and analgesic techniques are introduced. Consolidation and development of best management practices are necessary for sustained day surgery development.

Background and objective Respiratory burst is an essential component of the neutrophil's biocidal function. In vitro, sodium thiopental, isoflurane and lidocaine each inhibit neutrophil respiratory burst. The objectives of this study were (a) to determine the effect of a standard clinical induction/tracheal intubation sequence on neutrophil respiratory burst and (b) to determine the effect of intravenous lidocaine administration during induction of anaesthesia on neutrophil respiratory burst.

Methods Twenty ASA I and II patients, aged 18–60 years, undergoing elective surgery were studied. After induction of anaesthesia [fentanyl (2 μg kg−1), thiopental (4–6 mg kg−1), isoflurane (end-tidal concentration 0.5–1.5%) in nitrous oxide (66%) and oxygen], patients randomly received either lidocaine 1.5 mg kg−1 (group L) or 0.9% saline (group S) prior to tracheal intubation. Neutrophil respiratory burst was measured immediately prior to induction of anaesthesia, immediately before and 1 and 5 min after lidocaine/saline.

Results Neutrophil respiratory burst decreased significantly after induction of anaesthesia in both groups [87.4 ± 8.2% (group L) and 88.5 ± 13.4% (group S) of preinduction level (P < 0.01 both groups)]. After intravenous lidocaine (but not saline) administration, neutrophil respiratory burst returned towards preinduction levels, both before (97.1 ± 23.6%) and after (94.4 ± 16.6%) tracheal intubation.

Conclusion Induction of anaesthesia and tracheal intubation using thiopentone and isoflurane, inhibit neutrophil respiratory burst. This effect may be diminished by the administration of lidocaine.

Background and objective Epidermolysis bullosa is a rare, genetically determined disorder characterized by excessive susceptibility of the skin and mucosa to separate from the underlying tissues after mechanical trauma. Patients suffering from this disease may have multiple medical problems, but the risk of anaesthesia is attributed mainly to oropharyngeal involvement; airway management may be hazardous and preservation of mucosa and skin integrity problematical. There is a paucity of data in the literature concerning the perioperative management of children with epidermolysis bullosa. We present our experience of managing 54 general anaesthetics (and two local anaesthetics) over the past 20 years.

Methods The case notes of 16 children with epidermolysis bullosa were reviewed. The children underwent surgical procedures under local or general anaesthesia over a 20-year period.

Results Fifty-four general and two local anaesthetics were administered for 58 procedures in 10 children (mean age 12.6 years). Surgical procedures included oesophageal dilatation (24), insertion/revision of gastrostomy (16), dental procedures (10), hand surgery (2), skin biopsy (2) and others (4). Anaesthesia was induced by inhalation in 73.4% of patients and the airway was maintained with an endotracheal tube in 64.8%. Monitoring of anaesthesia was performed with pulse oximetry (89%), whereas electrocardiography and non-invasive blood pressure monitoring were used in 16.6% of cases each. The mean duration of anaesthesia was 64 min. Tracheal intubation was difficult in two of the five children who were intubated. Mucocutaneous blistering occurred in three children, otherwise there was no attributable morbidity.

Conclusion With maximal skin and mucous membrane protection, anaesthesia in children with epidermolysis bullosa may be undertaken with few sequelae.

Background and objective In a randomized, placebo-controlled, double-blind trial, we compared the efficacy of dolasetron and metoclopramide in preventing postoperative nausea and vomiting in women undergoing hysterectomy.

Methods Patients were allocated randomly to one of three groups: group A (n =50) received 50 mg dolasetron orally, group B (n =50) received 20 mg metoclopramide intravenously and placebo orally, group C (n =50) received placebo orally. If patients complained of retching or vomiting, or if patients demanded an antiemetic, 1.25 mg droperidol was administrated intravenously. To quantify postoperative nausea and vomiting the following score was used: 0 =no nausea, 1 =nausea, 2 =retching, 3 =single vomiting, 4 =multiple vomiting. The Raatz test was used to analyse postoperative nausea and vomiting (PONV) scores.

Results Dolasetron reduced the postoperative nausea and vomiting score significantly (P <0.02 vs. metoclopramide; P <0.0001 vs. placebo). Metoclopramide also reduced the postoperative nausea and vomiting score (P <0.02 vs. placebo). Fisher's exact test showed a significant reduction of vomiting in the dolasetron group compared with metoclo-pramide-treated patients (P <0.007) and placebo-treated patients (P <0.000006) and a significantly lower rate of nausea in comparison to the placebo group (P <0.009). There were no significant differences between the metoclopramide and the placebo groups (in Fisher's exact test). The use of postoperative droperidol per patient was significantly lower in the dolasetron group (P <0.04 vs. metoclopramide; P <0.0001 vs. placebo) than in the metoclopramide (P <0.02 vs. placebo) and in the placebo groups.

Conclusions Oral dolasetron is more effective than either metoclopramide given intravenously or placebo for preventing vomiting after hysterectomy. It also was significantly superior to either metoclopramide or placebo concerning the PONV score and the need for droperidol rescue.

Background and objective Inflammatory liver dysfunction in rats leads to a prolonged vecuronium-induced neuromuscular blockade due to insufficient metabolism. A coexisting resistance against the drug partly counteracts this prolongation. The present study investigates the pharmacodynamics of atracurium whose metabolism does not depend on liver function.

Methods Male Sprague–Dawley rats (n = 14; 290 ± 30 g) were randomly allocated to either a group in which liver inflammation was induced by intravenous injection of 60 mg kg−1 heat-killed Corynebacterium parvum or to a control group. On day 5 after injection, liver function was assessed using the aminopyrine breath test. Under propofol anaesthesia, duration of action of atracurium (4.8 mg kg−1) was measured by evoked mechanomyography (stimulation of the sciatic nerve; contraction of the gastrocnemius muscle). Nitric oxide concentrations, as variables for the severity of the inflammation, were assessed by measurement of nitrite/nitrate plasma concentrations.

Results In C. parvum-injected rats, nitrite/nitrate plasma concentrations were increased (972 ± 597 vs. 25 ± 7 μmol L−1), the aminopyrine turnover was depressed (1.7 ± 0.4% vs. 3.5 ± 0.5%), and the atracurium-induced neuromuscular blockade was shortened (372 ± 128 s vs. 1081 ± 234 s).

Conclusions A systemic inflammatory response syndrome with liver dysfunction results in decreased sensitivity to atracurium. Further investigations are needed regarding a possible up-regulation of acetylcholine receptors or an increased protein binding of atracurium during sepsis to clarify reasons behind this phenomenon.

Background and objective Interaction of intravenous anaesthetic agents with voltage-dependent potassium channels significantly correlates with clinical concentrations. If potassium channels were to play an important part in anaesthesia, one might expect different effects at the molecular level of those anaesthetics that show different clinical effects. Our aim was to analyse the interaction of general anaesthetics with voltage-dependent K channels.

Methods Whole cell patch-clamp experiments were analysed in detail in order to compare the effects of two clinically diverse intravenous hypnotics, ketamine and propofol, on voltage-dependent potassium channels in human neuroblastoma SH-SY5Y cells.

Results Both anaesthetics inhibited the potassium conductance in a concentration-dependent and reversible manner with IC50-values of 300μM and 45μM for ketamine and propofol respectively. Whereas ketamine shifted the midpoint of current activation by maximally 14 mV to more hyperpolarized potentials, propofol had the opposite effect on the activation midpoint. Current inhibition by ketamine increased with voltage but decreased with propofol at higher membrane potentials. Propofol but not ketamine induced concentration-dependent but voltage-independent decline, akin to inactivation, of the voltage-dependent potassium channels.

Conclusions The anaesthetics differed not only in their clinical profiles but they also showed differential actions on voltage-dependent potassium channels in several ways. This provides additional evidence for the hypothesis that voltage-dependent potassium channels play an important role in anaesthesia.

Background and objective The efficiency of intraoperative autotransfusion in scoliosis surgery is poorly known but needs to be evaluated, not least because of the large blood losses in these patients. This is a retrospective analysis of transfusion requirements of 43 such patients.

Methods Records from 43 patients were studied. During surgery, the shed blood was salvaged and washed in an autotransfusion device (AT1000 Autotransfusion Unit®) and a suspension of red cells was reinfused.

Results Fifty-eight per cent of the intraoperative blood loss was salvaged. The total blood loss during the patients' hospital stay was calculated from the haemoglobin balance; 24% of this loss was salvaged by the device. Moreover, 36 of the patients needed allogeneic blood transfusion.

Conclusion The efficiency of the autotransfusion device was relatively low in relation to the total extravasation, mainly because the postoperative blood loss is substantial.

Background and aim Compound A generation and accumulation in sevoflurane anaesthesia is dependent on fresh gas flow. We investigated the extent of generation of compound A.

Methods After Institutional Review Board approval and informed consent, patients with normal renal function were randomized to receive either sevoflurane (n = 33) or isoflurane (n = 43) minimal flow anaesthesia (0.5 L min−1) for at least 2 h under standardized conditions. Compound A concentrations were quantified and blood and urine samples were taken to assess renal involvement. Both groups were comparable.

Results No significant differences concerning blood chemistry and urine measurements were found. The maximum mean compound A concentration was observed 90 min after flow reduction being 40±9p.p.m. at a corresponding mean sevoflurane concentration of 2.1 ±0.5 vol%. Mean inspiratory compound A exposure was 102±l33p.p.mh−1.

Conclusion Compound A concentrations using 0.5 L min−1 fresh gas flow and a heated absorber were higher than previously published values using an inflow of 1 Lmin−1. Compound A exposure was similar to other clinical studies which did not show changes in renal and hepatic function.

Background and objective Patients undergoing coronary artery bypass grafting often require volume loading after operation. In this situation hypertonic saline may be beneficial in restoring the haemodynamic balance and removing excess extravascular fluid.

Methods Forty coronary artery bypass grafting patients were randomly assigned to receive either hypertonic saline 7.5% (20 patients) or 0.9% saline (20 patients) as a single dose of 4 mL kg−1 over 30 min in the postoperative rewarming phase in the intensive care unit.

Results Mean arterial pressure increased in the hypertonic saline group from 82 ± 10 (SD) to 104 ± 17 mmHg (P = 0.002 vs. the normal saline group), and the cardiac index rose from 2.3 ± 0.5 to 3.4 ± 0.8 L min−1 m2 (P = 0.002 vs. the normal group). The haemodynamic effect of hypertonic saline lasted only about 1 h. Diuresis was greater in the hypertonic saline group both at 1 h (hypertonic saline: 490 ± 274 vs. normal saline: 204 ± 130mL; P = 0.001) and 10 h (hypertonic saline: 1952 ± 554vs. normal saline: 1421 ± 514mL; P = 0.003).

Conclusions No adverse effects were seen. The hypertonic saline had a strong diuretic effect and may be beneficial in coronary artery bypass graft patients after operations. This is because of its value as a short-term plasma expander and the diuresis eliminates excessive fluid from the body. A larger study is needed to determine whether the benefits outweigh the possible side-effects in these patients.

Background and objective The incidence and clinical impact of perioperative myocardial infarction during coronary artery bypass graft surgery vary greatly depending upon the diagnostic criteria applied. Fatal perioperative myocardial infarction has a less arguable diagnosis and clinical impact. The aim of this paper is to find out the risk factors for fatal myocardial infarction after coronary surgery.

Methods Data from 1561 consecutive patients, who underwent coronary revascularization during a 10-month period, have been retrospectively analysed. After an univariate analysis for pre- and intraoperative risk factors, a multivariate model (logistic regression analysis) was settled.

Results Preoperative use of subcutaneous/intravenous heparin, a heparin sensitivity index <1.3 and need for a thromboendarterectomy of the left anterior descending coronary artery are independent risk factors for fatal myocardial infarction. The relative risk for fatal myocardial infarction was about 2 in the case of preoperative heparin use or heparin sensitivity index <1.3 and 5.5 in the case of thromboendarterectomy of the left anterior descending coronary artery.

Conclusions In patients undergoing coronary artery bypass surgery, preoperative anticoagulation management with heparin may represent a risk factor for fatal myocardial infarction. Patterns of heparin resistance, whether or not due to heparin pretreatment, seem to be closely related to fatal myocardial infarction.

Background and objective Hypothermia may alter the disposition of opioids. Because opioids are commonly used as analgesics in the postoperative period, it is of clinical interest to clarify whether perioperatively developed hypothermia affects postoperative opioid requirements.

Methods Fifty-nine patients undergoing subtotal hysterectomy were prospectively randomized and either treated intraoperatively with forced air warming, or served as controls covered with conventional blankets without active warming. Both groups received postoperative patient-controlled analgesia with the opioid ketobemidone. Total analgesic requirements, demands, analgesic requirements over 6-h intervals and pain scores were measured for 48 h. Core temperature at the tympanic membrane and ambient room temperature were measured during the perioperative period.

Results There were no postoperative differences in analgesic requirements or pain intensity between normothermic and hypothermic patients. Patients treated with warm air had an up to 1°C higher core temperature from 0.5 h after anaesthesia induction until almost 2 h postoperatively. The actively warmed patients also had a lower intraoperative blood loss than the hypothermic patients (186 ± 27 mL vs. 308 ± 47 mL; P < 0.05).

Conclusion In a clinical setting, opioid requirements do not seem to be affected by mild postoperative hypothermia after lower abdominal surgery.

Background and objective Efficacy and side–effects of piritramide (pirinitramide) and morphine, given intravenously for postoperative analgesia after hysterectomy, were compared in a randomized controlled double-blind trial in 92 ASA class I–III patients.

Methods Administration was investigator–controlled during the first 90 min and subsequently via a patientcontrolled device. Visual analogue scales for pain intensity and verbal rating scales for side-effects were taken repeatedly.

Results Median visual analogue scores for pain intensity on a 100-mm scale 4, 8 and 24 h after surgery were 10, 8.5 and 5mm in the piritramide group and 18, 10 and 8.5mm in the morphine group. These differences are neither statistically nor clinically significant. Median values for nausea on a verbal rating scale from 0 to 3 were zero for both groups at all times with similar ranges. There was no difference in number of episodes of vomiting and retching and usage of antiemetics. The mean amount of piritramide used for initial titration was 15.2 mg; the respective amount of morphine was 15.4 mg.

Conclusions In this setting the two agents are equally effective and show a similar profile of sideeffects.

Ambulatory surgery is growing worldwide. The challenge of providing anaesthesia for longer and more complex surgery in sicker and elderly patients is a reality. To maintain the safety and good outcomes of ambulatory anaesthesia, high-risk patients will need to be evaluated carefully. Anaesthetic techniques that use short-acting drugs and minimize postoperative morbidity and mortality should become the focus. Policies on management of postoperative pain, nausea, vomiting, voiding and discharge from hospital will maintain good outcome measures.

Background and objective Few and conflicting data are available regarding the changes of plasma potassium concentration during acute respiratory acidosis in human beings. This study compares the acute changes in plasma potassium concentration in acutely hypercapnic patients and in non–hypercapnic patients during general anaesthesia.

Methods Thirty-three patients undergoing interventional rigid bronchoscopy were studied. Ventilation of the lungs was randomly conducted using either spontaneous–assisted ventilation or intermittent negative–pressure ventilation. All patients received the same anaesthetic protocol. Arterial blood gases and osmolality, and plasma concentrations of glucose, sodium, potassium and chloride were measured.

Results Intraoperatively, PaCO2 was higher during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (9±1.8 vs. 5.4±1.2 kPa, P < 0.001) and the pH was also lower during spontaneous-assisted ventilation than during intermittent negative-pressure ventilation (7.24±0.07 vs. 7.4 ±0.08, P < 0.001). Plasma potassium concentration remained similar in both groups (3.8± 0.2mmolL−1 with spontaneous–assisted ventilation vs. 3.7± 0.4mmol L−1 with intermittent negativepressure ventilation).

Conclusion Acute respiratory acidosis does not affect plasma potassium concentration.

Background and objective Laparoscopic and open surgery have been compared with conflicting results regarding their systemic responses. The sensitivity of biochemical markers that are used to discriminate between the stress responses to different types of surgery varies from study to study. We wanted to evaluate the stress response and the sensitivity of clinical and biochemical stress markers in patients undergoing laparoscopically assisted vaginal or abdominal hysterectomy.

Methods We performed a case-control study with patients undergoing laparoscopically assisted vaginal hysterectomy (n=20) or abdominal hysterectomy (n=20). Pain scores were assessed at rest and during coughing, and active leg elevation and fatigue scores using a visual analogue scale. In 10 patients of each group, haematocrit, white cell count, C-reactive protein, glucose, cortisol, adrenocorticotrophic hormone, β-endorphin immunoreactivity, interleukin-6 and urine excretion of epinephrine and norepinephrine were measured preoperatively and during the first 44 postoperative hours.

Results The most sensitive symptoms and markers of the systemic response were pain scores during mobilization, fatigue scores, C-reactive protein and interleukin-6 (P < 0.01 in all comparisons). Pain scores at rest, and all other laboratory markers of the systemic response, did not discriminate between the two types of surgery.

Conclusion Follow-up of postoperative pain scores during mobilization and fatigue levels might be an easy tool for the evaluation of postoperative recovery. Using an identical anaesthetic technique, the neuroendocrine response was of the same magnitude after both types of surgery.

Background and objective Although there is concern that cibenzoline, an antidysrhythmic drug for the treatment of ventricular and supraventricular dysrhy-thmias, may be associated with dose-dependent inhibition of myocardial contractility there are few reports about the relationship between myocardial metabolism and cardiac function when it is used. The present study was designed to investigate the effects of cibenzoline on cardiac function and metabolism. The effects of cibenzoline on cardiac function and myocardial metabolism were assessed in the isolated rat heart-lung preparation.

Methods Thirty-two male Wistar-ST rats were divided into four groups: control, and those to receive cibenzoline, either 300, 900 or 3000 ngmL−1. The cibenzoline was administered into the perfusate 5min after the start of perfusion. Heart rates in the 3000ngmL−1 group were significantly lower than those in the control group. Cardiac output in the 3000 ng mL−1 group at 15 and 30 min was significantly lower than in the control group. In all groups, values for %LV dP/df max (the ratio of values at each time to those at 5 min) at 20, 25, 30 min were significantly higher than at 5min. Myocardial adenosine tripho-sphate concentration in the 3000ngmL−1 group was significantly lower than in controls. There was no difference between groups in the lactate/pyruvate ratio.

Conclusion The therapeutic range of cibenzoline has few effects on cardiac function and metabolism, although concentrations 10 times greater may cause a deterioration in myocardial metabolism.

Background and aim This study assessed the accuracy of using capnography with a modified, hollow gum elastic bougie in predicting tracheal intubation, and its effectiveness as a method of apnoeic oxygenation.

Methods Patients were randomly allocated to having the gum elastic bougie inserted, under anaesthesia, in the trachea or the oesophagus. End-tidal carbon dioxide measurements were made at 10 and 20 s. The position of the gum elastic bougie was correctly predicted in 89.2% of patients. We tested the apnoeic oxygenation on an anaes-hetic simulator model, which is housed in the Scottish Anaesthesia Simulator Centre, Stirling, UK.

Results The time taken for the oxygen saturation to fall to 90% was significantly prolonged when the gum elastic bougie was used for apnoeic oxygenation.

Conclusion The modification of the gum elastic bougie allows a more objective assessment of correct placement than the previous tactile method. The current design of bougie is unsuitable but can be modified.

Background and objective We have assessed the analgesic efficacy and side-effects of neostigmine when added to lidocaine for axillary brachial plexus block, in a prospective, randomized, double-blind, placebo-controlled study.

Methods We studied 34 ASA I or II patients undergoing elective ambulatory carpal tunnel release. Axillary brachial plexus block was performed using a peripheral nerve stimulator to locate the median nerve. All patients were administered 1.5% lidocaine 450 mg and epinephrine 5 μg mL−1. Patients were allocated randomly to one of two groups. Neostigmine 500|ig was added in group N, and saline 1 mL in group S.

Results The duration of analgesia did not significantly differ between groups [mean (SD)]: 812.5 (456.9) for group S vs. 746.7 (474.1) min for group N (P >0.05). The need for supplementary analgesia did not significantly differ between groups: 4.4 (1.5) extra doses for group S vs. 3.8 (2.2) extra doses for group N (P>0.05). Visual analogue pain scores and occurrence of side-effects did not significantly differ between groups.

Conclusion Neostigmine does not seem to be of clinical value for peripheral nerve blocks.

Background and objective Variability in blink duration was examined to see whether it was sensitive to sevoflurane sedation at 0.05 and 0.1 minimum alveolar concentration (MAC).

Methods Blinks were measured with an infrared transducer in eight subjects. Sedation was scored using a visual analogue scale (VAS).

Results At baseline, 0.05 and 0.1 MAC sevoflurane, respectively, the overall median value of blink duration and its interquartile range were 95 (80–110) ms, 198 (163–245) ms and 210 (130–980) ms. The median percentage of blinks exceeding 500 ms was 0% (0–0.7%), 33.3% (25.5–34.7%) and 25% (15.7–63.3%) respectively. Values during 0.05 and 0.1 MAC sevoflurane were significantly different from baseline (P < 0.035) but not from each other. Baseline visual analogue scales showed large intersubject variability. Compared with baseline, VAS scores were higher at 0.05 MAC (P < 0.035) but not at 0.1 MAC. After discontinuing sevoflurane, median blink duration returned to baseline with a recovery half-life of 2.6 min (R2 = 0.95).

Conclusion Blink duration is a sensitive measure of sevoflurane sedation even at 0.05 MAC.

Background and objective It is claimed that local anaesthetics have antimicrobial properties. Our aim was to investigate the antimicrobial effects of different concentrations of ropivacaine, bupivacaine, lidocaine and prilocaine on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans.

Methods All local anaesthetic dilutions were exposed to microorganisms for 0, 30, 60, 120, 240 min at room temperature. The inoculums taken from diluted suspensions were reinoculated on blood agar and incubated for 18–24 h at 35°C and then the colonies were counted.

Results Ropivacaine did not inhibit any of the microorganisms tested. Bupivacaine reduced the viable cells of P. aeruginosa at 0.5% and 0.25% solutions. Lidocaine 5% and 2% and prilocaine 2.0% dilutions reduced the viable cells of all microorganisms tested. Prilocaine 1.0% reduced the viable cells of E. coli, S. aureus and P. aeruginosa. Lidocaine 1% reduced only the viable cells of P. aeruginosa and prilocaine 0.5% reduced only E. coli.

Conclusion Ropivacaine had no antimicrobial effect on microorganisms tested. Bupivacaine showed poor antimicrobial effectiveness. Lidocaine and prilocaine had more powerful antimicrobial effects than the other two local anaesthetics.