There is disagreement concerning the role of nitric oxide (NO) in general anaesthesia. The present study was conducted to determine whether the anaesthetic drug isoflurane alters levels of NO metabolites, NOx (NO2 and NO3), in the hippocampus of rats during and after anaesthesia. Results showed resting hippocampal NOx levels of about 20 pmol in freely moving control rats. Five minutes after the induction of isoflurane anaesthesia (4.72%=4 minimum alveolar concentrations, detected by righting reflex), there was loss of the righting reflex coincident with a significant elevation in hippocampal NOx levels. During isoflurane anaesthesia, the maximum NOx concentration rose ≈2.4-fold higher than control levels; the NO3 level increased about 5-fold higher than resting levels. NOx levels returned to control levels following discontinuation of the anaesthetic. When rats were pre-treated with L-NG-nitro arginine methyl ester, an NO synthase-inhibitor, the isoflurane-induced increases in NOx were markedly suppressed. D-NG-nitro arginine methyl ester was ineffective in preventing these neurochemical changes, thus indicating the stereoselective nature of the inhibition by L-NG-nitro arginine methyl ester. Furthermore, L-NG-nitro arginine methyl ester pre-treatment likewise prevented increases in both NO2 and NO3 levels. When rats were exposed to 80% nitrous oxide in oxygen, there was loss of the righting reflex but no change in hippocampal NOx levels. These findings indicate that isoflurane increases production of hippocampal NO and that this may be pertinent to general anaesthetic drug effects.

In a randomized double-blind study, 60 children, aged 4–7 years, undergoing dental extractions of six or more teeth under day-case general anaesthesia, were assigned to receive either tramadol drops 1.5 mg kg−1 (n=31), or placebo (normal saline) (n=29), 30 min before surgery. In addition, all received anxiolytic premedication of oral midazolam 0.5 mg kg−1 (max7.5 mg) at the same time. No differences were seen in behaviour, respiratory or cardiovascular assessments. In both groups, 93% were drowsy preanaesthetic, 3% were asleep but rousable and less than 4% exhibited minor distress. At induction, mild weeping occurred in 9.7% of the tramadol group and 6.9% of the placebo group (p>0.05). Active awake recovery took 48.8 min, SD 32.6 in the tramadol group and 36.4 min, SD 29.6 in the placebo group (p>0.05). Post-operative analgesia (paracetamol 120 mg) was given to 19.4% of the tramadol group compared with 82.8% of the placebo group (p>0.05), after which the Hannalah objective pain scale scores were comparable. Analysis of the Oucher six faces pain scale showed significantly better analgesia in the tramadol group at all time points, the pain score being half that of the placebo group at 60 min and one third from 60 to 120 min (p>0.05). No adverse respiratory or cardiovascular effects were seen. For children undergoing multiple extractions, 10.7, SD 3.0, effective postextraction analgesia was provided.

A prospective multicentre pilot study was undertaken in 20 Italian hospitals to assess the influence of a routine pre-operative chest radiograph on anaesthetic management and to characterise which patients might benefit from it. A total of 6111 patients undergoing elective surgery and submitted for routine pre-operative chest radiograph were enrolled. Abnormal pre-operative chest radiographs were reported in 1116 patients (18.3%). Pre-operative chest radiograph altered the anaesthetic management (i.e. useful pre-operative chest radiograph) in 313 patients (5.1%). Male sex, age >60 years, ASA classes ≥3, respiratory diseases, and the presence of two or more co-existing diseases were significantly related to the probability of a useful pre-operative chest radiograph using multivariate analysis (P<0.01). The classification of the surgical intervention and, of the co-existing diseases, the presence of cardiac disease had a very low influence when determining the probability that a pre-operative chest radiograph would be useful. A simple equation includes the effects of all the variables studied and allows calculation of the probability of a useful pre-operative chest radiograph. This study indicates that in healthy, female, ≤60-year-old patients, submitted for standard surgery, the probability of a useful pre-operative chest radiograph ranges from 0.2% to 3.5% according to the hospital. The probability increases in male or elderly subjects, or in the presence of co-existing respiratory diseases, or in ASA classes ≥3, but there is a wide variation between hospitals.

We evaluated the efficacy of a newly developed prototype illuminated flexible catheter to facilitate tracheal intubation through the intubating laryngeal mask and compared this light-guided technique with the conventional blind tracheal intubation through the intubating laryngeal mask. The illuminated flexible catheter consists of a completely flexible thin plastic catheter, a bulb attached to its distal end, a 15-mm concentric adapter at its proximal end connected with a battery and a power switch. The device is placed into a silicone tracheal tube in such a way that the bulb protrudes from the distal end of the tracheal tube. One hundred adult patients, ASA I–III, scheduled to undergo propofol/fentanyl/atracurium anaesthesia for elective surgery were studied. All participants underwent a randomized double comparative cross over trial with respect to the tracheal intubation technique through the intubating laryngeal mask. The light guided tracheal intubation was performed as follows; the tracheal tube preloaded with the illuminated flexible catheter was inserted through the intubating laryngeal mask and by observing the glow in the neck was advanced into the trachea. Whenever resistance was felt during insertion, appropriate adjusting man oeuvres were performed. The intubating laryngeal mask was inserted successfully in all patients. The success rate for the blind and light-guided technique was 91% and 100%, respectively (P=0.003). The mean (±SD) duration including appropriate intubating laryngeal mask placement and tracheal intubation, was significantly lower in the light-guided tracheal intubation technique, than with the blind tracheal in-tubation (31±8s vs. 43±18s; P=0.0001). We conclude that the use of an illuminated flexible catheter carries advantages either in optimizing the intubating laryngeal mask position in the laryngopharynx or in achieving a quick and safe light-guided advancement from laryngopharynx into the trachea.

A study of 56 patients was undertaken to determine whether there is a difference in the effect of the laryngeal mask airway and the endotracheal tube on the vocal tract after short-duration anaesthesia. All the patients were interviewed pre- and post-operatively.In 43 patients, it was possible to assess the larynx using videoendoscopy and videostrobolaryngoscopy both pre- and post-operatively. Selected acoustic characteristics were investigated in 51 patients pre- and 18–24 h post-operatively. Thirty-four patients that did not have anaesthesia were used as an age-matched control.

The interview showed, that patients in the LMA group complained less frequently of having post-operative complained less frequently of having post-operative demonstrated minor lesions of the vocal tract in six patients in the ETT group and in one patient in the LMA group. Of the 12 voice variables evaluated, there was no significant difference in any parameter between the two groups. Both groups had a higher fundamental frequency post-operatively.

This prospective, randomized and double-blinded study was designed to evaluate the anti-emetic efficacy of a combination of ondansetron and metoclopramide in 100 ASA physical status I and II children of either sex and 1–15 years of age undergoing elective surgery for strabismus. A standardized anaesthetic technique and post-operative analgesia were used for all the children. Children were divided into four groups. They received saline, metoclopromide 250 μg kg−1, ondansetron 150 μg kg−1 or a combination of metoclopramide 150 μg kg−1 and ondansetron 100 μg kg−1 intravenously immediately after the insertion of an intravenous cannulae. There were no differences between the groups in their age, gender, weight, duration of surgery, number of muscles subjected to surgery or intravenous fluids received. In the first 24 post-operative hours, 18 (72%) patients in the placebo group, 15 (60%) patients in the metoclopramide group, 10 (40%) patients in the ondansetron group and 11 (44%) patients in the combination group had nausea or vomiting. The overall incidence of post-operative nausea and vomiting was significantly (P<0.05) lower in the combination group and in the ondansetron group compared with the placebo group. Nine (36%) patients in both the placebo and the metoclopramide groups and one (4%) patient in the ondansetron group required rescue anti-emetic treatment. None of the patients in the combination group required rescue anti-emetic and this was significantly less (P <0.01) when compared with the placebo and the metoclopramide groups. Recovery and sedation scores were comparable in all the four groups. A combination of metoclopramide 150 μg kg−1 and ondansetron 100 μg kg−1 administered prior to surgery was not found to be more effective than ondansetron 150 μg kg−1 alone for the prophylaxis of nausea and vomiting following surgical repair of strabismus in paediatric patients.

In an attempt to attenuate the cardiovascular pressor response to laryngoscopy and intubation, 30 patients presenting for routine ophthalmic surgery were studied and were randomly allocated into two groups: group A (n=15) received direct laryngeal/tracheal lignocaine spray immediately before intubation; and group B (n=15) received orolaryngeal lignocaine spray before the induction of anaesthesia. In both groups, general anaesthesia was induced with thiopentone 3–5 mg kg−1, followed by atracurium 0.6 mg kg−1 to facilitate tracheal intubation. Laryngoscopy and endotracheal intubation caused a significant increase in heart rate, by 28% in group A and 23% in group B (P<0.05 in both), and in diastolic blood pressure, by 28% in group A and 24% in group B (P<0.05 in both). In group A, the systolic blood pressure also increased significantly (by 18%) after intubation, but there was no significant change in group B. In addition, the plasma lignocaine concentrations remained well below the toxic range in both groups. It was concluded that topical lignocaine administration as an orolaryngeal spray before the induction of anaesthesia is effective in reducing but not abolishing the pressor response to laryngoscopy and endotracheal intubation

It has been shown in healthy volunteers that a concentration of volatile anaesthetic lower than 1 minimum alveolar concentration provides unconsciousness. We tested the hypothesis that, using the electroencephalogram bispectral index, less than 1 minimum alveolar concentration of sevoflurane can produce unconsciousness in patients. Anaesthesia was induced and maintained with sevoflurane in N2O and O2 (33%) in 32 ASA I-II women undergoing laparoscopic tubal ligation. For the first patient, the sevoflurane concentration was adjusted to 1 minimum alveolar concentration with an end-tidal concentration of 0.7%. The electroencephalogram bispectral index values were used to determine the concentration to be used for the next patient. The ED50 (effective dose) measured using end tidal concentrations of sevoflurane for laparoscopic tubal ligation in a 40-year-old patient was 0.70% (CI 95%: 0.63–0.77) and ED95 0.83% (CI 95%: 0.75–0.90). None of the patients had any operation-associated recall. It is concluded that the sevoflurane concentration needed for laparoscopic tubal ligation is not lower than 1 minimum alveolar concentration.

Patients undergoing mitral valve surgery are at risk of left ventricular failure in the immediate post-operative period. In order to understand better the mechanisms of post-operative haemodynamic instability, we used transoesophageal echocardiography to assess the immediate response of the left ventricle to mitral valve replacement for mitral regurgitation or stenosis. A decrease in left ventricular preload, despite adequate filling pressures, was common to both groups and suggests the presence of diastolic dysfunction. A marked impairment in global systolic pump function was observed only in the regurgitation group and correlated with the left ventricular afterload. Transoesophageal echocardiography provides valuable information on the individual changes in left ventricular function and its determinants after mitral valve replacement that are not reflected by haemodynamic measurements.

The effects of bolus and infusion doses of propofol on histopathological changes in the rat pancreas are reported. After obtaining Hospital Ethics Committee approval, 75 female Wistar rats were assigned to three study groups. Groups I (n=30) and II (n=30) received 10 mg kg−1 intravenous bolus of propofol; with propofol administered to group II at an infusion rate of 10 mg kg−1 h−1 for 30 min immediately after the bolus doses. Group III (n=15) was used as the control group. Twenty-four hours after propofol administration blood samples and pancreatic tissue specimens were obtained under ether anaesthesia. Plasma cholesterol, triglyceride, amylase, and lipase levels were studied, and pancreatic tissues were examined under light microscopy. Plasma cholesterol and triglyceride levels were significantly higher in group II compared with the other groups. Differences between the groups in respect of plasma amylase and lipase levels were not statistically significant. Acute pancreatitis was observed under light microscopy, in three rats (10%) in group II, and in one rat (6.6%) in the control group. The pancreatic tissues of group I were normal. The incidence of acute pancreatitis in each of the groups was not significant. It is therefore suggested that, further controlled studies are needed to investigate the relation between pancreatitis and the use of propofol.

This study compared the effect of two anaesthetic techniques on the catecholamine levels in children undergoing ilioinguinal herniorrhaphy. Forty male paediatric patients ASA class I were allocated randomly to one of two groups: the control group (n=20) received general anaesthesia including intravenous fentanyl; and the caudal group (n=20) received caudal anaesthesia with bupivacaine 0.25% 1mL kg−1; combined with general anaesthesia but without opioids. Plasma adrenaline and noradrenaline concentrations were measured at induction, at the end of surgery and in the post-anaesthesia care unit (PACU). In the caudal group, there were significant decreases in the adrenaline and noradrenaline concentrations at the end of surgery and in the PACU compared with baseline concentrations. In the control group, there was a significant increase in PACU concentrations of adrenaline and noradrenaline compared with baseline concentrations. These findings suggest that the addition of a caudal block to general anaesthesia in children undergoing ilioinguinal herniorrhaphy decreases significantly the neurohormonal responses to surgery.

A telephone survey was undertaken of all UK centres (total 70) licensed for performing in vitro fertilization (IVF) and gamete intra-fallopian transfer (GIFT) by the Human Fertilisation and Embryology Authority (HFEA). The survey was carried out during the months of November and December 1997. Thirty-seven (52.1%) centres were in the NHS sector and 33 (47.8%) in the private sector. A response was available from 60 (84%) centres. A standard questionnaire was used which requested information about the procedures carried out, anaesthetic technique and pharmacological agents used. Forty-seven centres carried out IVF, two centres GIFT and 11 centres both. Out of 58 centres carrying out IVF, sedation was used in 28, general anaesthesia in 17, sedation combined with regional anaesthesia in seven and regional anaesthesia in one. Five centres gave a choice. Out of 22 centres using general anaesthesia for IVF, 12 used inhalational agents (isoflurane eight, enflurane four, sevoflurane two), eight used total intravenous anaesthesia (TIVA) with propofol and two centres inhalational agents or TIVA. Propofol was the induction agent in all but two centres. For IVF under sedation, 18 centres used midazolam, five used diazepam, three used opioids, one used entonox and the remaining ones a combination. When sedation was combined with regional anaesthesia, four centres used midazolam, two used propofol, one used midazolam with propofol, one used opioids and one used entonox. The regional technique in the 11 centres was either paracervical block with lignocaine (eight) or subarachnoid block with bupivacaine (three). Systemic analgesia was secured with fentanyl (22), pethidine (16), alfentanil (15), diclofenac (14), piroxicam (two), ketorolac (one) and ibuprofen (one). Five centres did not use any opioids; 40 centres did not use any non-steroidal agents (NSAIDs). Out of the 13 centres that carried out GIFT, 12 used general anaesthesia while the thirteenth gave the patient a choice between general or regional anaesthesia. 11 centres used inhalational agents (isoflurane nine, enflurane two) while two used TIVA with propofol; propofol was the induction agent used in six centres while thiopentone was used in five. The range of analgesics was wide – fentanyl in six centres, alfentanil in three, morphine in two, diclofenac in five and ketorolac in one. Two centres did not use any opioids and seven centres did not use an NSAID. The only agreement at present appears to be that halothane is an unwise choice for IVF. No other technique has yet been proven to be either advantageous or detrimental.

The effects of hydroxyethyl starch on blood coagulation were investigated in 20 patients undergoing surgery to determine whether its use places recipients at risk of haemorrhage or thrombosis. The partial thromboplastin times are significantly prolonged; factor VIII activities and fibrinogen levels are decreased. After infusion of hydroxyethyl starch, no significant differences were detected in platelet count or prothrombin time. A decreased platelet aggregation was also found after the infusion of hydroxyethyl starch. According to our results, hydroxyethyl starch can cause haemorrhagic problems in patients when administered as a colloidal volume-expanding agent.

Nausea and vomiting are common side effects of opioids administered for pain control. This double-blind, randomized, parallel-group study evaluated the anti-emetic efficacy and tolerability of single intravenous (i.v.) doses of ondansetron 8 mg, ondansetron 16 mg and metoclopramide 10 mg in the treatment of opioid-induced emesis. Adult patients undergoing low emetogenic surgical procedures, using a standardized anaesthesia regimen were assessed for 24 h following administration of study anti-emetic to treat established post-surgical opioid-induced emesis. A total of 4511 patients were enrolled of whom 1366 experienced opioid-induced emesis and received randomized study medication. Ondansetron 8 mg and 16 mg were significantly better than metoclopramide 10 mg (P < 0.05) for both complete control of emesis, complete control of nausea and other efficacy measures. There were no significant differences between the two ondansetron groups. All three treatments were well tolerated. In conclusion, this large, multicentre study demonstrates that ondansetron is more effective than metoclopramide in the treatment of opioid-induced emesis following administration of post-surgical opioids to control pain.

Forty patients (> 65 years) undergoing hip arthroplasty or peripheral vascular surgery both associated with high risk for post-operative myocardial ischaemia were randomized to receive either spinal or general anaesthesia. Ambulatory ECG recording (Holter) until the third post-operative morning, a daily 12-lead ECG and serum creatine kinase and troponine concentrations were obtained. The number of ischaemic episodes, total duration of ischaemia and ischaemic minutes per hour were noted for each patient peri-operatively. Sixteen of the patients (40%) had post-operative myocardial ischaemia. An intra-operative increase in the plasma concentration of norepinephrine but not epinephrine was detected in the patients who later developed post-operative myocardial ischaemia. The increase in plasma norepinephrine concentrations correlated with the decrease in core temperature. The type of anaesthesia had no effect on the incidence of myocardial ischaemia during or after surgery. Our results suggests that intra-operatively decreased core temperature and the increase in plasma concentration of norepinephrine probably caused peripheral vasoconstriction leading to latent cardiac dysfunction. These events should be avoided in the patients at risk of post-operative cardiac ischaemia.

Elderly patients with hyperkalaemia often have low concentrations of plasma renin and aldosterone, perhaps secondary to reduced glomerular filtration and sympathetic insufficiency. The endocrine response to surgical stress and volume expansion during anaesthesia was studied in seven elderly patients with hyperkalaemia (mean age 87.7±SD 5.3 years), 18 elderly patients without hyperkalaemia (86.5±5.5 years), and 18 younger patients (52.6±7.2 years) as controls. Base-line values, in hyperkalaemic elderly patients, for plasma renin activity and plasma aldosterone concentration were 0.8±0.3 ng mL−1 h−1 and 2.8±0.8 pg mL−1 respectively (significantly lower than in the younger patients), and 287±42 pg mL−1 for plasma atrial natriuretic peptide levels, which were significantly higher. The plasma renin activity and aldosterone concentrations in elderly patients with hyperkalaemia were at all times lower, but not significantly, than those of the elderly patients without hyperkalaemia. The atrial natriuretic peptide concentrations (351±48 pg mL−1) in the hyperkalaemic elderly were significantly higher 90 min after induction of anaesthesia than in the normokalaemic elderly (108±38 pg mL−1). Hormone concentrations in the hyperkalaemic patients did not change during anaesthesia, but plasma atrial natriuretic peptide concentrations increased significantly in the normokalaemic elderly, and plasma renin activity and aldosterone of the younger patients increased significantly during anaesthesia. These results indicate that plasma renin activity, and the concentrations of aldosterone and of atrial natriuretic peptide in elderly patients with hyperkalaemia are unresponsive to surgical stress and volume expansion.

The anti-emetic effects of ondansetron and droperidol were evaluated in 134 ASA Grade I and II female patients, scheduled for laparoscopic cholecystectomy and minor gynaecological laparoscopic surgery, who were randomly assigned to receive ondansetron 4 mg or droperidol 75 μg kg−1 intravenously immediately after induction of anaesthesia. The patients were assessed 1, 6, 12 and 24 h after surgery for intensity of nausea and number of vomiting episodes. In the case of the patients undergoing laparoscopy, vomiting episodes occurred in a similar proportion in patients treated with ondansetron or droperidol, with the probability of the Type I error of 0.05 and the Type error II of 0.1. Although there was no difference between the two groups in emetic episodes following all laparoÍscopic procedures and gynaecological laparoscopic surgery, there was a significant difference between these parameters after laparoscopic cholecystectomy. The patients treated with ondansetron experienced a lower intensity of nausea (P=0.04) after laparoscopic cholecystectomy, less frequent severe nausea (P=0.02) and episodes of vomiting (P=0.04) when compared with those in the droperidol group. We conclude, that despite the result the droperidol prophylaxis appears to be an effective alternative to ondansetron in all patients undergoing laparoscopy, the ondansetron prophylaxis is superior to droperidol in patients undergoing laparoscopic cholecystectomy.

In order to elucidate temporal changes in airway reflex responses to prolonged tracheal intubation, 14 patients anaesthetized with sevoflurane were studied. In each spontaneously breathing patient with an endotracheal tube in place, the end-tidal concentration of sevoflurane was slowly decreased from the initial value of 1.3% until signs of airway irritation were observed. The value of end-tidal sevoflurane concentration at which the airway reflexes occurred (Tar)and the types of airway reflex response elicited at onset of airway reflex response were determined during the periods immediately before (presurgical period) and after surgery (post-surgical period), with an interval ranging from 2 to 7 h between the two periods. There was no significant difference in the values of Tar between the presurgical period(0.6±0.3%, mean±SD) and the post-surgical period(0.7±0.1%). There was a considerable difference in the type of airway reflexes elicited during the two different periods; the initial responses during the presurgical period were the apnoeic reflex and/or forceful expiratory efforts, whereas the initial response during the post-surgical period, in the majority of patients, was the swallowing reflex. Our results indicate that there may be adaptation mechanisms responsible for temporal changes in airway protective reflexes after prolonged endotracheal intubation in surgical patients.

The efficacy of anaesthetic premedication has been assessed using sedative scores or a visual analogue scale. However, in both it may be difficult to exclude evaluators’ subjectivity or a placebo effect. Plasma concentration of catecholamines may also be useful for the assessment of patient anxiety. Recently bispectral electro-encephalographic analysis has been developed, and the bispectral index monitor has been reported to give measurements which correlate well with the depth of sedation. In the present study, we have examined the relation between bispectral index values and plasma catecholamine concentrations after oral diazepam premedication. Twenty-eight patients scheduled for elective surgery were randomly assigned to one of two groups: diazepam premedication group (group D(+), n=14) and no premedication group (group D(−), n=14). The patients were premedicated orally with diazepam 10 mg and roxatidine 75 mg in group D(+), and with roxatidine 75 mg only in group D(−) 90 min before arrival in the operating theatre. After patients arrived in the operating theatre, the bispectral index monitor was applied. Venous blood samples(6 mL) were collected in the case of patients in group D(+) for the measurement of plasma catecholamines levels using high-performance liquid chromatography. The bispectral index level (mean±SD) in group D(+): 93.5±773.5 was significantly lower than that in group D(−): 96.1±1.8(P<0.05). There was a significant correlation between bispectral index and plasma norepinephrine levels (r=0.567, P<0.05). The present study suggests that the bispectral index monitor may detect the effect of oral diazepam premedication.