Enflurane (Ēthrane*) and isoflurane (forane*): A comparison with nine general anaesthetics administered with passive hyperventilation

Studies were carried out on 22 large, male, mongrel dogs at two-week intervals, in a crossover design, to determine the metabolic, blood-gas and cardiovascular effects, and the rate of recovery to steady ambulation from a surgical depth of general anaesthesia administered with passive hyperventilation. To prepare the animal, induction of anaesthesia was accomplished with 20 mg/kg body weight of 2 per cent thiopentone, trachéal intubation and inhalation of 50 per cent nitrous oxide and oxygen. After attachment of recording equipment and drawing of control blood samples, a respirator was attached to the anaesthetic circuit to provide passive hyperventilation by providing pulmonary ventilation of 15 ml/kg body weight at the rate of approximately 25 cycles per minute for 90 minutes, adding an anaesthetic concentration of methoxyflurane, chloroform, trichlorethylene, halothane, halothane-ether, azeotrope, isoflurane, cnflurane, diethyl ether, or fluorexcne from an out-of-circuit calibrated vapourizer. Thiopentone and Innovar were also tested and were given by an intravenous drip infusion. Nitrous oxide 50 per cent was given with 50 per cent oxygen with all the maintenance agents. No muscle relaxants were used and no stimulants were administered at the end of the test period. The data support the advantages of passive hyperventilation which have been reported. Full oxygénation is maintained; mild respiratory alkalosis is generally safe with particular respect to the incidence of ventricular arrhythmias and effecton myocardiac contractility (as judged by the lack of appreciable hypotension); metabolic acidosis does not occur except with diethyl ether; excess lactate accumulation is no greater than with isocarbic pulmonary ventilation and is negligible except with diethyl ether. Myocardial oxygen consumption is probably not increased with halogenated anaesthetics except with fluroxene, chloroform and trichlorethylene. The hypotension that occurred with some of the anaesthetics (~30 per cent) is an inherent effect of a surgical depth of general anaesthesia on the peripheral vascular resistance and occurs also with the non-depolarizing skeletal muscle relaxants. Full recovery after anaesthesia with passive hyperventilation is not delayed significantly, since deep general anaesthesia was not greatly prolonged. Recovery of spontaneous respiration was rapid after diethyl ether (<10 minutes) but took approximately 30 minutes (means of 18 to 35 minutes) with the other agents. Steady ambulation usually took approximately 45 minutes longer (means of 25 to 71 minutes) due to muscle weakness after isoflurane, enflurane and methoxyflurane and a prolonged hypnotic effect of the other agents. Neuromuscular disturbances did not occur with enflurane or isoflurane in any of the tests in spite of fairly deep anaesthesia and induction of hypocarbia. On the basis of these animal experiments, there appear to be no obvious disadvantages to the employment of moderate passive hyperventilation for surgical anaesthesia with inhalational or parenteral anaesthetics.     

Comparative study of general and spinal anesthesia in elderly women in hip surgery

The choice between regional versus general anaesthesia for elderly patients undergoing hip surgery is debated. It is vitally important to see if the type of anaesthetic administered affects per- and postoperative morbidity and mortality. Seventy women more than 75 yr old suitable for spinal anaesthesia were included in this study. They were randomly divided into two groups: in one (n = 35), general anaesthesia was given with sodium thiopentone, fentanyl, enflurane and vecuronium; in the other (n = 35), spinal anaesthesia was performed with 3 ml 0.5% bupivacaine in isobaric solution. During the anaesthetic period, there were no statistically significant differences between both groups in systolic arterial pressure falls or in increases in the heart rate X systolic arterial pressure product. No serious cardiovascular collapse was encountered. Seven patients (20%) receiving general anaesthesia had mental changes against four only (14.2%) in the spinal group. In patients having general anaesthesia, 22.9% developed bronchopneumonia as opposed to 8.6% in the spinal anaesthesia group (p less than 0.05). The mortality rate at three months was rather similar in the two groups. It was concluded that, in order to reduce the incidence of postoperative central dysfunction and bronchopneumonia, spinal anaesthesia should be preferred in geriatric patients for lower limb surgery.     

Challenges that opioid-dependent women present to the obstetric anaesthetist

A retrospective casenote review was performed to identify anaesthetic challenges relevant to the opioid-dependent obstetric population. Medical records showed that of the 7,449 deliveries during a 24 month period, 85 women (1.1%) were taking regular opioids such as methadone and/or heroin. Of these 67 (79%) received anaesthetic services, ten of whom (11.7%) were referred antenatally. Forty opioid-dependent women (47%) received epidural analgesia in labour compared with the overall hospital rate of 38%. Twenty-three women (27%) delivered by caesarean section: five received general anaesthesia, five combined spinal anaesthesia, five spinal anaesthesia and eight epidural anaesthesia. Twenty opioid-dependent women (23.5%) had documented problems related to labour analgesia and 17 (74%) had problems with analgesia after caesarean section. A variety of postoperative analgesia methods were administered in addition to maintenance methadone. Fourteen patients (16.5%) had difficult intravenous access and seven "arrest" calls were documented. One anaesthetist was exposed to hepatitis C. This review demonstrates the demands placed on obstetric anaesthetic services by opioid-dependent women. Early antenatal referral for anaesthetic review is recommended.     

Insulin secretion and glucose utilization are impaired under general anesthesia with sevoflurane as well as isoflurane in a concentration-independent manner

Purpose The dose-dependent effects of sevoflurane and isoflurane anesthesia on glucose tolerance were compared in humans. Methods A prospective, randomized clinical study was conducted in 30 patients. The 30 patients were divided randomly into three sevoflurane anesthesia groups (0.5, 1.0, and 1.5 minimum alveolar concentration [MAC]) and three isoflurane anesthesia groups (0.5, 1.0, and 1.5 MAC). Induction of anesthesia was accomplished by inhalation of the volatile agent and nitrous oxide. After induction, anesthesia was maintained at the designated MAC for 15 min without surgical stimulation. The intravenous glucose tolerance test (IVGTT) was performed in these 30 patients while they were under general anesthesia and again several days after surgery in 5 of these patients while they were awake, as a control. Results The insulinogenic index (change in concentration of immunoreactive insulin/change in glucose concentration), the acute insulin response, and rates of glucose disappearance were significantly lower in all anesthesia groups than in the control group. However, the insulinogenic index, acute insulin response, and the glucose disappearance rate did not differ significantly among the six anesthesia groups. Conclusion Sevoflurane anesthesia impairs glucose tolerance to the same degree as does isoflurane anesthesia. Glucose intolerance during sevoflurane or isoflurane anesthesia is independent of agent and dosage up to 1.5 MAC.     

The effects of general anaesthesia on the asphyxiated foetal lamb in utero

The effects of anaesthetic agents, per se, on the asphyxiated foetus are difficult to quantitate clinically. Anaesthesia is often necessary in foetal distress, however, to effect a rapid delivery. To investigate the effect of general anaesthetic agents commonly used for Caesarean section we administered these agents to 18 chronically prepared pregnant ewes with asphyxiated foetuses in utero. The foetuses were asphyxiated by partial occlusion of the umbilical cord until foetal arterial pH had decreased from 7.30 to a range of 7.08-7.13. The animals were divided into three groups: Group A which received no anaesthesia and thus served as a control, Group B which received thiopentone (3 mg . kg-1) intravenously followed by 50 per cent nitrous oxide and 0.5 per cent halothane in oxygen for 15 minutes, and Group C which received thiopentone (3 mg . kg-1) followed by one per cent halothane in oxygen for 15 minutes. Foetal cerebral, myocardial, and renal blood flows were measured by injection of radioactive microspheres after production of asphyxia and after 5 and 15 minutes of anaesthesia. General anaesthesia in both groups B and C abolished the hypertension and bradycardia produced by foetal asphyxia secondary to umbilical cord occlusion. There were no significant differences between Groups B and C in foetal pH, PCO2, or PO2. Two foetuses in the nitrous oxide group died after ten minutes of anesthesia, but the aetiology of the sudden demise is unclear. We conclude that general anaesthesia abolishes the foetal response to umbilical cord occlusion and does not improve foetal oxygenation or acid-base status.     

Comparison of alfentanil,fentanyl and enflurane as supplements to general anaesthesia for outpatient gynaecologic surgery

We compared two narcotic/N2O anaesthetic techniques and an inhalational anaesthesia/N2O technique for outpatient surgery in 59 women undergoing short gynaecological procedures. All patients received droperidol 0.625 mg IV, thiopentone and 70 per cent N2O in O2 plus either alfentanil (15 micrograms.kg-1), fentanyl (1.5 microgram.kg-1) or enflurane. The narcotics were given in a double-blind fashion and all anaesthetic techniques were assigned randomly. Cardiorespiratory parameters remained stable in all groups, with few clinically important changes occurring. Recovery was significantly faster in the group receiving alfentanil, with the time to respond to verbal commands and the time to establish alertness significantly faster than with either fentanyl or enflurane. All techniques provided satisfactory anaesthesia; however, the patients receiving alfentanil had significantly more adverse events than those receiving fentanyl.     

Effects of isoflurane-nitrous oxide anaesthesia on insulin secretion in female patients

In vitro studies suggest that volatile anaesthetic agents may directly inhibit insulin secretion. It is unclear if supplementation of anaesthesia with isoflurane impairs insulin secretion. We performed a 5- g i.v. glucose tolerance test in 21 patients before and during anaesthesia which was maintained with either 1 or 2 MAC of isoflurane in nitrous oxide, or no volatile agent. The study was carried out before surgery to avoid the influence of hormonal responses to trauma. A significant glycaemic response occurred during both i.v. glucose tolerance tests in all three groups of patients. Serum insulin concentrations were measured and the acute increase in insulin concentration at 3 min and area under the curve for 15 min were calculated. Both variables decreased significantly in all three groups during the tests performed under anaesthesia compared with tests carried out before anaesthesia.      

Hepatic metabolic ability during anasthesia Evaluation of antipyrine half-lives and their relation to enflurane metabolism

The antipyrine (phenazone) half-life was determined in 20 surgical patients to discover whether there are changes in hepatic metabolic rate during or immediately after anaesthesia compared with the pre-anaesthetic rate. Nine patients received enflurane (mean duration 8.6, SD 2.0 hours) and six patients had a balanced anaesthetic without enflurane (duration 4.4, SD 3.3 hours). A further five patients received a spinal anaesthetic with bupivacaine. The changes in antipyrine half-life were inconsistent, and there was no evidence of competitive metabolic inhibition by general anaesthesia. Antipyrine half-lives did not correlate with serum fluoride levels or urinary fluoride excretion in the case of enflurane. The mean serum inorganic fluoride concentration rose to 29 mumol/litre, and two patients had potentially nephrotoxic concentrations (64 and 50 mumol/litre) after 8 hours of exposure to enflurane though without any evident harmful effects.     

Comparative repercussions of general and spinal anesthesia on the psychological functions of the aged subject

Although worsening cerebral function in the elderly is often said to be due to anaesthesia, it still remains to be proved that anesthesia acts on an elderly patient's psychological make-up. This study aimed to compare the psychological effects of general or spinal anaesthesia on 35 patients more than 70-yr old under repair of a subcapital femoral fracture, after having excluded 63 patients. They were randomly divided into two groups, the first receiving a spinal anaesthetic with 1.5 mg.kg-1 prilocaine (RA; n = 19), and the others a general anaesthetic with 5 mg.kg-1 thiopentone, dextromoramide, nitrous oxide and enflurane (GA; n = 16). None of the patients wer given a premedication. They underwent a battery of six psychological tests before and 36 h after surgery, all carried out by the same physician. Six patients in GA group and three in RA group developed a transient fall in mean blood pressure just after anaesthetic induction (not significant). There were no significant differences between the two groups in age, sex distribution, ASA class and performance in the tests, both before and after surgery. Individual psychological scores did not differ either. In the RA group, the postoperative tests were even better carried out than before surgery (p less than 0.05). It could therefore be concluded that anaesthesia alone has little impact on the psychological status of elderly patients.     

Randomized comparison of outcome after propofol-nitrous oxide or enflurane-nitrous oxide anaesthesia in operations of long duration

A randomized, prospective, comparative study was performed to evaluate induction characteristics, haemodynamic changes and recovery in 60 ASA I-II patients undergoing mainly gynaecological laparotomies with either propofol or thiopentone-enflurane anaesthesia. The propofol group (n = 30) received 2 mg.kg-1 propofol for induction of anaesthesia followed by propofol infusion. The thiopentone-enflurane group (n = 30) received thiopentone 4 mg.kg-1 for induction followed by enflurane (0.5-2 per cent). All patients received nitrous oxide (66 per cent] in oxygen begun one minute after tracheal intubation, and fentanyl (1.5 micrograms.kg-1) four minutes prior to induction. Other drugs administered during or after anaesthesia were similar among the groups. Haemodynamic measurements were similar between propofol and enflurane groups except after tracheal intubation when the mean arterial pressure was lower in the propofol group (P less than 0.05). The propofol group had significantly less (P less than 0.01) emesis in the recovery room than the enflurane group. The propofol group experienced significantly less (P less than 0.05) dizziness, depression/sadness and hunger than the enflurane group in the postoperative period as assessed with a visual analogue questionnaire. We conclude that propofol provided better outcome than enflurane in terms of these nonvital but annoying outcome measures after relatively long intra-abdominal operations.     

Effect of Epidural Analgesia on Glucose Tolerance During Surgery

Intravenous glucose tolerance tests were performed on 12 surgical patients the day before surgery and during surgery. Six patients were anaesthetized with enflurane and six were operated on during an epidural lumbar blockade (Th₈-S₅). In the general anaesthesia group the plasma glucose concentration was significantly higher after the intraoperative glucose load than after the preoperative load. The pre- and intraoperative glucose tolerance tests were identical in the epidural group. Pre- and intraoperative glucose disappearance rates and plasma insulin responses were similar in the two groups, indicating that the observed differences in plasma glucose were caused by differences in hepatic glucose release, rather than differences in peripheral glucose utilization.     

Anaesthesia for non-cardiac surgery in heart-transplanted patients

This review documents the anaesthetic management, haemodynamic function and outcome in 18 of 86 heart-transplanted recipients, who returned for 32 non-cardiac surgical procedures at the Toronto Hospital from 1985 to 1990. General anaesthesia was administered in eight of the 27 elective operations and four of the five emergency operations. Induction medications included thiopentone (2–4 mg· kg^?1), fentanyl (1–7 μg· kg^?1) and succinylcholine (1–1.5 mg· kg^?1). Anaesthesia was maintained with a combination of oxygen /nitrous oxide and isoflurane or enflurane. Muscle relaxation was maintained with vecuronium or pancuronium. No delayed awakening or unplanned postoperative ventilation was observed. Neuroleptanaesthesia was administered to 63.0% and 20.0% of the elective and emergency operations, respectively. The anaesthetics included fentanyl (25–100 ng) and midazolam (0.5–1.5 mg) or diazemuls (2.5–5.0 mg). Spinal anaesthesia (75 mg lidocaine) was administered to only two of the 27 elective operations. No important haemodynamic changes were observed in any anaesthetic group, but lower systolic BP was found after induction and during maintenance periods in the patients who received general anaesthesia than in those who received neurolept-anaesthesia. However, no anaesthesia-related morbidity or mortality was noted. This suggests that general, neurolept- and spinal anaesthesia do not affect haemodynamic function or postoperative outcome in heart-transplanted recipients undergoing subsequent non-cardiac surgery.     

The site of airway irritation during induction of anaesthesia

The aim of this investigation was to study the role of the nasal airway in mediating upper airway reflexes during induction of anaesthesia when the commonly used irritant inhalational anaesthetic agent enflurane is used. In a prospective randomised study, 40 ASA 1 & 2 day-case patients undergoing body surface surgery were recruited. Following intravenous induction using propofol, 20 patients received enflurane administered via a laryngeal mask airway (LMA), the anaesthetic vapour therefore bypassing the nasal airway. In the other group, 20 patients received enflurane anaesthesia administered using a face mask, the nasal airway therefore being exposed to inhalation anaesthetic. We were unable to demonstrate any significant (p < 0.05) differences between the two groups in relation to upper airway complications (cough, breath holding, laryngeal spasm, bronchospasm and excitement). Previous work has identified the nose as a possible important reflexogenic site for upper airway reflexes in humans during anaesthesia. We have been unable to demonstrate any difference in upper airway complications when the nasal airway was included or excluded from exposure to irritant anaesthetic vapours, when administered in a clinical setting.     

Clinical study on glucose intolerance and insulin response in obstructive jaundice

Insulin responses to oral glucose loads were studied in patients with obstructive jaundice and compared with those of other liver diseases (fatty liver, chronic hepatitis and liver cirrhosis), pancreatic diseases, and definite diabetes mellitus. Compared with their corresponding glucose intolerance, high insulin responses were characteristic in fatty liver, chronic hepatitis and liver cirrhosis, and insulin responses and insulinogenic index decreased in chronic hepatitis and liver cirrhosis as glucose intolerance progressed. In obstructive jaundice with the pancreatic ducts stenotic or obstructed, insulin responses were suppressed in comparison with their corresponding glucose intolerance, and also insulinogenic index were below 0.5 in most of the cases. However, in obstructive jaundice with the pancreatic ducts intact, high insulin responses were observed in almost half of the cases with insulinogenic index above 0.5, and insulin response and insulinogenic index decreased as glucose intolerance progressed. While most cases of fatty liver, chronic hepatitis and liver cirrhosis with insulinogenic index above 0.5 were distributed in non-diabetes zone in sigma BS-sigma IRI plane (Kosaka's), those with insulinogenic index below 0.5 were distributed in intermediate zone. Most cases with obstructive jaundice with pancreatic ducts stenotic or obstructed, had insulinogenic index below 0.5 and were distributed in diabetes zone. However, half of cases with obstructive jaundice with pancreatic ducts intact, had insulinogenic index above 0.5 and their distribution in non-diabetes zone, while the other half had insulinogenic index below 0.5 and their distribution in diabetes zone. Therefore, it may be concluded that insulin responses increase at the early stage of obstructive jaundice mainly under influence of liver dysfunction itself, but that insulin response is suppressed at later stage of obstructive jaundice as pancreatic islets are affected.     

Glucose-induced insulin secretion in uremia: effects of aminophylline infusion and glucose loads

To explain mechanisms responsible for derangement of insulin release in uremia, we investigated glucose metabolism through three different tests in 14 patients with end-stage chronic renal failure. These tests were: intravenous glucose tolerance test with 0.33 g/kg of glucose solution (IVGTT); IVGTT with 0.5 g/kg of glucose solution (IVGTT2); IVGTT during aminophylline infusion (IVGTT + A). Twelve of the patients had IVGTT repeated after two to four months of thrice-weekly regular hemodialysis (IVGTT3). In each test we measured plasma glucose (G), immunoreactive insulin (IRI) and C-peptide. We also calculated glucose constant decay (K), insulin production (IRI area), insulinogenic index (IGI), and insulin resistance index (RI). Twenty-nine healthy volunteers formed the normal controls for IVGTT. As compared to controls, during IVGTT uremic patients showed significantly lower values in K, IRI area and IGI, and showed a significant RI value increase. During IVGTT2, IRI are values were higher than during IVGTT but IGI and K values were unchanged. During IVGTT + A both IRI area and IGI values were higher than during IVGTT. After hemodialysis treatment (IVGTT3) K, IRI areas and IGI increased significantly as compared to the predialysis period. K increase after hemodialysis correlated directly to IGI increase and inversely to RI changes. IGI increase during IVGTT3 was directly correlated to IGI rise during IVGTT + A. From these data we infer that defective insulin release in uremia is due to a decrease of beta-cell glucose sensitivity rather than to their functional exhaustion. An impaired adenyl cyclase-cAMP system may have an important role in the pathogenesis of this abnormality.     

A comparison of thiopentone/isoflurane anaesthesia vs propofol infusion in children having repeat minor haematological procedures

We have performed a randomized, cross over study in 22 children suffering from acute leukaemia, who underwent repeated anaesthesia for bone marrow aspiration and lumbar puncture. For their first anaesthetic, the children (aged 3–10 years old) received, either a thiopentone/isoflurane anaesthetic or intravenous propofol, both supplemented with nitrous oxide. On a second occasion they received the alternative technique. Of those children receiving thiopentone/isoflurane, 32% had significant coughing during anaesthesia, two progressing to laryngospasm requiring 100% oxygen. None of the patients receiving propofol had a respiratory disturbance ( P =0.016). 68% of the children preferred the propofol anaesthetic. Only one child in the thiopentone/isoflurane group preferred this technique. Twenty-seven per cent had no preference. There was no significant difference in length of anaesthetic time ( P =0.07) or the time taken for recovery ( P =0.17) between the two groups. There was a large individual variation in propofol requirements and movement was common during stimulation of patients in this group, though this did not adversely affect the surgical procedure.     

Insulin response to glucose in hypermetabolic burn patients.

Fifty-four intravenous glucose tolerance tests were performed in 12 normal individuals and 21 thermally injured patients. In the 17 hypermetabolic burn patients studied between the 6th and 16th days postinjury, fasting blood glucose was elevated (111 +/- 7 mg/100 ml, mean +/- SE compared to 85 +/- 3 in controls, P less than 0.001), but the instantaneous proportionality constant for glucose disappearance (k) was similar to that obtained in normal individuals (5.27 +/- 0.51, 100/min vs 4.01 +/- 0.58 in normals, NS). Fasting serum insulin concentrations were comparable in the 12 normals and 17 hypermetabolic burn patients (22 +/- 3muU/ml in normals vs 22 +/- 2), as was fasting insulin corrected for fasting glucose (24 +/- 3 in normals vs 21 +/- 3, NS), initial insulin response (0-10 min delta insulin, 58 +/- 13 in normals vs 67 +/- 10, NS) or total insulin response corrected per unit glycemic stimulus (insulinogenic index, 0.48 +/- 0.10 in normals vs 0.52 +/- 0.07, NS). With time following injury, the proportionality constant for glucose disappearance and insulin response decreased, and these alterations were related to the posttraumatic weight loss. In the 5 convalescent patients studied between the 37th and 90th days postinjury, glucose and insulin dynamics appeared similar to those observed in starved man. In these burn patients, hypermetabolism and negative nitrogen balance occurred in association with a normal insulin response to glucose. Increased hepatic gluconeogenesis appears to be characteristic of the catabolic response to this stress, directed by increased glucagon and catecholamines, not a decrease in fasting insulin or dampened insulin response.     

Anaesthesia for laparoscopy

This is a report about five anaesthetic techniques for laparoscopy. Propofol and etomidate were used for total intravenous anaesthesia. Propofol, etomidate and thiopentone were used as induction agents prior to inhalational anaesthesia with isoflurane and nitrous oxide. Fentanyl was used for analgesia. Induction with propofol and thiopentone was rapid. Etomidate induction was characterised by myoclonus. Maintenance was smooth with inhalational anaesthesia. Of the groups that received total intravenous anaesthesia, propofol provided stable anaesthesia but required extra bolus doses. Recovery was the most rapid following total intravenous anaesthesia with propofol. Postoperative side effects were much lower after propofol. No difference was observed between the groups with regard to changes in arterial blood pressure and heart rate.     

THE HYPERGLYCAEMIC RESPONSE TO DIFFERENT TYPES OF SURGERY AND ANAESTHESIA

The rise in blood sugar during anaesthesia without surgery andduring surface, thoracic and intra-abdominal surgery, was measured.In patients anaesthetized primarily with thiopentone there wasno significant rise without surgery and the rise was, in general,proportional to the stress of surgery, the largest being duringintra-abdominal operations. Findings were similar in anotherseries of patients anaesthetized primarily with propanidid.Five anaesthetic techniques were also compared during intra-abdominalsurgery. In all nitrous oxide and tubocurarine were used andthere was a bigger rise in patients in whom anaesthesia wasinduced with propanidid than in those who had thiopentone. Theaddition of 1 per cent halothane or phenoperidine 5 mg to thethiopentone/nitrous oxide/tubocurarine technique, led to a significantlysmaller response. When a technique using droperidol/fentanyl/tubocurarinewas employed the hyperglycaemic response was similar to thatwith thiopentone induction.     

Propofol infusion anaesthesia for Caesarean section

Two propofol infusion regimens and a standard general anaesthetic were compared in thirty Chinese women undergoing elective Caesarean section. After induction of anaesthesia with propofol 2 mg.kg-1, ten patients received propofol 6 mg.kg-1.hr-1 and nitrous oxide 50 per cent in oxygen while ten were given propofol 9 mg.kg-1.hr-1 with 100 per cent oxygen. The other ten patients received thiopentone 4 mg.kg-1 and nitrous oxide 50 per cent in oxygen with enflurane one per cent. Maternal recovery times and psychomotor performance were recorded. Neonates were assessed by Apgar scores, neurologic and adapative capacity scores (NACS) and umbilical cord blood gas analysis. Haemodynamic changes were similar immediately following induction but the low propofol infusion group had the best haemodynamic stability subsequently. Recovery times were fastest in the low-infusion group but there were no differences in later postbox testing. Neonatal Apgar scores and umbilical blood gas analysis were similar but NACS at two hours were poorer in the high infusion group. A propofol infusion coupled with nitrous oxide appears to be a satisfactory technique for Caesarean section.