Posture and the spread of hyperbaric bupivacaine in parturients using the combined spinal epidural technique

This study was undertaken to analyze the effect of posture on the spread of hyperbaric bupivacaine in pregnant women using a combined spinal extradural technique, and to assess the quality of analgesia provided by 10 mg bupivacaine when using this technique. Fifty parturients undergoing elective Caesarean section under regional anaesthesia were randomly allocated to receive 2.0 ml hyperbaric bupivacaine 0.5% in either the sitting or left lateral position. Spinal injection was performed with a 27 gauge, 120 mm long spinal needle using a single space combined spinal extradural technique. The onset time to analgesia at T₄, and grade 3 motor block was on average 7.7 min and 6.9 min respectively in the lateral group, compared with 10.8 min (P < 0.05) and 9.4 min (P < 0.05) in the sitting group. Nine women in the sitting group and one woman (P < 0.05) in the lateral group required epidural supplementation. Hypotension occurred in 48% of the parturients in the lateral group and in 13% (P < 0.05) of the parturients in the sitting group. Nausea was noted in 61% of the parturients in the lateral group and in 22% (P < 0.05) of the parturients in the sitting group. There was no difference between the two groups in neonatal outcome. Overall, the position of the patient during induction of spinal anaesthesia does influence the rate of onset of analgesia and motor blockade. Injection of 10 mg hyperbaric bupivacaine in the sitting position would not provide adequate analgesia for Caesarean section when using a single space combined spinal extradural technique.     

Disposition of propofol infusions for caesarean section

The disposition of propofol was studied in women undergoing elective Caesarean section. Indices of maternal recovery and neonatal assessment were correlated with venous concentrations of propofol. After induction of anaesthesia with propofol 2.0 mg.kg-1, ten patients received propofol 6 mg.kg-1.hr-1 with nitrous oxide 50 per cent in oxygen (low group) and nine were given propofol 9 mg.kg-1.hr-1 with oxygen 100 per cent (high group). Pharmacokinetic variables were similar between the groups. The mean +/- SD Vss = 2.38 +/- 1.16 L.kg-1, Cl = 39.2 +/- 9.75 ml.min-1.kg-1 and t1/2 beta = 126 +/- 68.7 min. At the time of delivery (8-16 min), the concentration of propofol ranged from 1.91-3.82 micrograms.ml-1 in the maternal vein (MV), 1.00-2.00 micrograms.ml-1 in the umbilical vein (UV) and 0.53-1.66 micrograms.ml-1 in the umbilical artery (UA). Neonates with high UV concentrations of propofol at delivery had lower neurologic and adaptive capacity scores 15 minutes later. The concentrations of propofol were similar between groups during the infusion but they declined at a faster rate in the low group postoperatively. Maternal recovery times did not depend on the total dose of propofol but the concentration of propofol at the time of eye opening was greater in the high group than the low group (1.74 +/- 0.51 vs 1.24 +/- 0.32 micrograms.ml-1, P less than 0.01). The rapid placental transfer of propofol during Caesarean section requires propofol infusions to be given cautiously, especially when induction to delivery times are long.     

Continuous opioid infusions for neurosurgical procedures: a double-blind comparison of alfentanil and fentanyl

The ability of continuous infusions of opioids to control hypertension at the end of neurosurgical procedures without compromising prompt emergence was studied in patients undergoing craniotomy for supratentorial tumours. Four infusion regimens were compared in a randomized double-blind fashion; three of alfentanil and one of fentanyl. Low-dose alfentanil was administered to nine patients (35.1 micrograms.kg-1 then a continuous infusion of 16.2 micrograms.kg-1.hr-1); mid-dose alfentanil to eight patients (70.2 micrograms.kg-1 then 32.4 micrograms.kg-1.hr-1); high-dose alfentanil to eight patients (105.3 micrograms.kg-1 then 48.6 micrograms.kg-1.hr-1). Eight additional patients were given fentanyl (8.3 micrograms.kg-1 then 1.6 micrograms.kg-1.hr-1). Using published values for the pharmacokinetic variables of alfentanil and fentanyl, modelling predicted stable concentrations of 60, 120, 180 ng.ml-1 for the alfentanil infusion regimens respectively and 2 ng.ml-1 with the fentanyl regimen. Maintenance anaesthesia comprised the opioid infusion, 50% N2O in O2 and isoflurane titrated to control mean arterial pressure (MAP) within 20% of ward MAP. Isoflurane was discontinued after closure of the dura. Nitrous oxide was discontinued at the same time as reversal of neuromuscular blockade. The opioid infusion was discontinued with closure of the galea. A greater time-averaged isoflurane concentration was required to control MAP within the prescribed limits in the low alfentanil group (ANOVA; P less than 0.05). The PaCO2 at two, five and 30 min after extubation were not different among groups. The times from discontinuing N2O to eye opening and tracheal extubation were not different. The time to follow commands was longer in the low alfentanil group (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Clinical and pharmacokinetic aspects of the combination of meperidine and prilocaine for spinal anaesthesia

The aim of this study was to determine whether the addition of a small dose of prilocaine could augment the spinal block induced by meperidine and affect intrathecal meperidine pharmacokinetic behaviour. Spinal anaesthesia was performed in 60 men scheduled for endoscopic resection of a prostatic adenoma or bladder tumour under spinal anaesthesia. They were allocated randomly to receive either 1 mg.kg-1 meperidine (Group 1, n = 30), or 1 mg.kg-1 meperidine plus 0.5 mg.kg-1 prilocaine (Group 2, n = 30). Blood samples were collected prior to and for 24 hr after spinal injection in 24 patients (12 in each group). Plasma meperidine levels were assayed by gas chromatography. Complete motor block was achieved in all Group 2 patients, but was incomplete in seven of Group 1 (P less than 0.05). The onset of both motor and sensory blocks was shorter (P less than 0.01) in Group 2 and the duration was longer (P less than 0.05). Coadministration of prilocaine modifies meperidine pharmacokinetic behaviour. The area under curve was 48% greater (P less than 0.01) and Cmax was higher in Group 2 than in Group 1, 145.8 +/- 42.2 vs 107 +/- 20.5 ng.ml-1 (P less than 0.001). No evidence of respiratory depression was noted in any of the patients. Despite the increase in plasma meperidine concentrations, no side effects were observed. The plasma concentrations remained at one third to one sixth the levels reported to induce a respiratory depression. It is concluded that the addition of prilocaine to meperidine improves motor and sensory block during surgery and alters meperidine kinetics without producing major side effects.     

Anesthésie péridurale pour la chirurgie de la cheville et du pied: influence de la position assise

The effects of the sitting position on the quality of both sensory and motor blockade of segments L5 and S1 and the haemodynamic consequences during epidural anaesthesia were studied on 39 patients undergoing ankle or foot surgery. After insertion of an epidural catheter with the patient in the lateral position, 19 patients were kept sitting for 15 min following the injection of the local anaesthetic and 20 remained supine for the duration of anaesthesia (control group). All patients received a dose of 20 ml of 1.73% carbonated lidocaine with epinephrine 1:200,000. The quality and time of onset of the sensory blockade for segments L1-S2 as well as its cephalad spread were comparable in both groups. Fourteen patients of the sitting group achieved motor blockade of more than three of five myotomes compared with five patients in the supine group (P less than 0.001). The maximum decrease in mean arterial pressure occurred sooner in the sitting group (14 +/- 9 min) than in the control group (21 +/- 10 min; P less than 0.01) and was more severe (-24 +/- 10% vs -16 +/- 10% respectively; P less than 0.05). Our results indicate that placing the patient in the sitting position for 15 min after inducing epidural anaesthesia does not influence caudal sensory blockade but does increase the depth of motor blockade.     

Decreased glucose utilization during prolonged anaesthesia and surgery

We studied the influence of prolonged anaesthesia and surgery on glucose metabolism by means of the euglycaemic insulin clamp method in eight patients who underwent prolonged surgery. Eleven patients who underwent surgery of short duration served as a control group. Plasma concentrations of catabolic hormones were measured simultaneously. Glucose utilization during prolonged anaesthesia, (PA) group, was lower than that in the control group (P less than 0.01) (glucose utilization 7.59 +/- 0.73 mg.kg-1.hr-1 in the control group vs 4.03 +/- 0.71 mg.kg-1.hr-1 in PA group respectively). There were no significant differences in plasma catecholamine and glucagon concentrations between the PA and control groups. Plasma-free fatty acid levels increased significantly in the PA group before the euglycaemic insulin clamp (free fatty acid level: 0.496 +/- 0.053 mmol.L-1 in the control group, vs 0.834 +/- 0.103 mmol.L-1 in the PA group at the pre-clamp period, P less than 0.01). Tissue resistance to exogenous insulin increased during prolonged anaesthesia and surgery although there were no significant changes in plasma catabolic hormone levels.     

A comparison of the myocardial metabolic and haemodynamic changes produced by propofol-sufentanil and enflurane-sufentanil anaesthesia for patients having coronary artery bypass graft surgery

The purpose of this study was to compare propofol-sufentanil with enflurane-sufentanil anaesthesia for patients undergoing elective coronary artery bypass graft (CABG) surgery with respect to changes in (1) haemodynamic variables; (2) myocardial blood flow and metabolism; (3) serum cortisol, triglyceride, lipoprotein concentrations and liver function; and (4) recovery characteristics. Forty-seven patients with preserved ventricular function (ejection fraction greater than 40%, left ventricular end diastolic pressure less than or equal to 16 mmHg) were studied. Patients in Group A (n = 24) received sufentanil 0.2 microgram.kg-1 and propofol 1-2 mg.kg-1 for induction of anaesthesia which was maintained with a variable rate propofol (50-200 micrograms.kg-1.min-1) infusion and supplemental sufentanil (maximum total 5 micrograms.kg-1). Patients in Group B (n = 23) received sufentanil 5 micrograms.kg-1 for induction of anaesthesia which was maintained with enflurane and supplemental sufentanil (maximum total 7 micrograms.kg-1). Haemodynamic and myocardial metabolic profiles were determined at the awake-sedated, post-induction, post-intubation, first skin incision, post-sternotomy, and pre-cardiopulmonary bypass intervals. Induction of anaesthesia produced a larger reduction in systolic blood pressure in Group A (156 +/- 22 to 104 +/- 20 mmHg vs 152 +/- 26 to 124 +/- 24 mmHg; P less than 0.05). No statistical differences were detected at any other time or in any other variable including myocardial lactate production (n = 13 events in each group), time to tracheal extubation and time to discharge from the ICU. We concluded that, apart from hypotension on induction of anaesthesia, propofol-sufentanil anaesthesia produced anaesthetic conditions equivalent to enflurane-sufentanil anaesthesia for CABG surgery.     

Comparaison de l’incidence sur le saignement de deux techniques anesthésiques midazolam-alfentanil versus propofol-alfentanil lors de la cure d’otospongiose

This study was performed to compare the incidence of bleeding associated with two anaesthetic techniques during otolaryngological microsurgery. Twenty-eight venous interpositions for otospongiosis have been carried out at random either under local anaesthesia combined with light sedation (midazolam 0.1 mg.kg-1 and alfentanil 0 micrograms.kg-1) or using general anaesthesia (propofol 2.5 mg.kg-1, then 9 mg.kg-1.hr-1 and alfentanil 30 micrograms.kg-1, then 15 micrograms.kg-1). The patients' lungs were mechanically ventilated. Every ten minutes, heart rate, arterial blood pressure and FETCO2 were observed. Bleeding was assessed on a four-point scale and evaluated according to its duration and the annoyance that it caused. General anaesthesia was clinically better tolerated. Heart rate and arterial blood pressure were lower than with general anaesthesia. The end-expiratory CO2 was 4.7 +/- 0.2 per cent. Bleeding was less frequent, lasted less time, but when it occurred the surgical disturbance was identical in the two groups. General anaesthesia produced a less bloody operating field and local anaesthesia required the cooperation of the patient.     

Alfentanil infusion for sedation in infants and small children during cardiac catheterization

We have analyzed several sedation techniques for paediatric cardiac catheterization which offer stable conditions for a few hours investigation, and maintain spontaneous breathing. In the present study, after premedication with oral flunitrazepam 0.1 mg.kg-1, 14 children aged 1-17 mo were sedated with an individually titrated alfentanil infusion. Every patient was sedated to a level which produced no reaction to pain or any discomfort. The induction dose and the maintenance requirement of alfentanil were 24 +/- 8 micrograms.kg-1 and 32 +/- 8 micrograms.kg-1.hr-1 (mean +/- SD), respectively. These doses were less in cyanotic than in acyanotic patients: 21 +/- 6 vs 28 +/- 8 micrograms.kg-1 and 29 +/- 10 vs 34 +/- 3 micrograms.kg-1.hr-1, respectively (P less than 0.05). The mean plasma concentration of alfentanil during maintenance of sedation was 79 +/- 23 ng.ml-1. Ventilation of two children was assisted for a short time after an incremental bolus of alfentanil. It is concluded that an alfentanil infusion technique with close monitoring of breathing is a practical sedation method for paediatric cardiac catheterization.     

Butorphanol compared with fentanyl in general anaesthesia for ambulatory laparoscopy

Butorphanol was compared with fentanyl as the narcotic component of general anaesthesia for ambulatory laparoscopic surgery. This double-blind, randomized study enrolled 60 healthy women who received equianalgesic doses of fentanyl 1 microgram.kg-1 (F, n = 30) or butorphanol 20 micrograms.kg-1 (B, n = 30) prior to induction of anaesthesia. Tracheal anaesthesia was maintained with nitrous oxide/oxygen, isoflurane, and succinylcholine by infusion. Intraoperatively, patients who received B demonstrated lower pulse rate before and after intubation (P less than 0.05, P less than 0.01) and lower diastolic blood pressure after intubation (P less than 0.01). Anesthesiologists judged the maintenance phase as satisfactory more often with B (P less than 0.05). Postoperatively, there were no differences in analgesic need. No major side-effects occurred in either group. Among minor side-effects, patients who received B reported postoperative sedation more often, 77% vs 37% (P less than 0.01), which occurred during the first 45 min of recovery (P less than 0.05). Discharge times were not different. On the first postoperative day, more subjects who received B were satisfied with their anaesthesia experience (P less than 0.05). Butorphanol 20 micrograms.kg-1 is an acceptable alternative analgesic in general anaesthesia for ambulatory laparoscopy.     

Low-dose sufentanil in major surgery

The purpose of this study was to assess the efficacy of sufentanil 1 micrograms.kg-1 during N2O-O2 and intermittent isoflurane anaesthesia in major non-cardiac surgery. Thirty-one patients (18 females, 13 males; mean age 47 yr), undergoing cholecystectomy received a 1 microgram.kg-1 bolus of sufentanil before the induction of anaesthesia with thiopentone. On average, three sufentanil increments were administered, to a total (bolus + maintenance) dose of 1.5 micrograms.kg-1. Cardiovascular stability was not achieved in eleven patients who then were given isoflurane. The arterial pressure decreased after sufentanil (P less than 0.05), reaching a nadir (mean 108/65 mmHg, heart rate 63 bpm) at one minute post-incision. Clinically important hypertension or hypotension did not occur in any patient. One patient, receiving beta-blocker therapy, required atropine to control bradycardia. Postoperative respiratory depression did not occur in patients who received less than one micrograms.kg-1.hr-1 with the last increment being given more than 20 minutes before the end of anaesthesia. Slight respiratory depression in the recovery room was reported in one patient, who had received a total of 1.3 micrograms.kg-1.hr-1 of sufentanil, and the last sufentanil increment 24 min before the end of surgery. The most frequently reported side-effects were nausea (35 per cent) and vomiting (23 per cent). Induction, maintenance and recovery from anaesthesia were rated as "good" in 87, 87, and 74 per cent of the cases, respectively, and "satisfactory" in the remainder. We conclude that this technique is valuable to assure good protection of the cardiovascular system without undue respiratory depression during recovery.     

Edrophonium priming alters the course of neuromuscular recovery from a pipecuronium neuromuscular blockade

This study was designed to investigate the effect of divided administration of edrophonium on the course of neuromuscular recovery from a pipecuronium neuromuscular blockade. During thiopentone-nitrous oxide-halothane anaesthesia 48 patients were given pipecuronium 70 micrograms.kg-1. Patients were randomly assigned to one of four groups (n = 12 in each) to receive either edrophonium 1 mg.kg-1 (Groups I and II) or edrophonium 0.75 mg.kg-1 (Groups III and IV). In Groups I and III (single-dose groups), edrophonium was administered as a single bolus dose. In Groups II and IV (divided-dose groups) edrophonium was administered as an initial dose of 0.25 mg.kg-1 followed three minutes later by either 0.75 or 0.50 mg.kg-1 respectively. Reversal was attempted at 20% spontaneous recovery of twitch height. Administration of edrophonium in divided doses (Groups II and IV) accelerated the reversal of the pipecuronium neuromuscular blockade. At ten minutes post-reversal, train-of-four (TOF) ratio recovery reached 0.75 or more in 12 (100%) and in ten (83%) patients in Groups II and IV respectively. Similarly, times to attain a TOF of 0.75 (SEM) were shorter in the divided-dose groups than in the single-dose groups (P less than 0.05), being 354.5 (38.7) and 398.3 (49.1) sec in Groups II and IV vs 705.4 (66.6) and 651.2 (54.3) sec in Groups I and III respectively. Time was counted from the first administration of edrophonium. It is concluded that administration of edrophonium in divided doses produced a faster reversal of residual pipecuronium-induced neuromuscular blockade than single bolus administration. Also, administration in divided doses reduced the requirements of edrophonium needed for reversal of pipecuronium neuromuscular blockade.     

Spinal anaesthesia for Caesarean section after Harrington instrumentation

A case is presented of a 33-yr-old parturient with Harrington fusion of her spine who received spinal anaesthesia with 15 mg hyperbaric bupivacaine for Caesarean delivery. Multiple attempts of needle insertion in both midline and paramedian at the L_3-4 interspace were unsuccessful, whereas the procedure was performed uneventfully at the midline of the L₅S₁ interspace. The anatomical considerations and difficulties in achieving reliable epidural anaesthesia after Harrington fusion are reviewed. Spinal anaesthesia performed at the L₅S₁ interspace may provide less technical difficulty and a more reliable result in such patients.     

Side effects during continuous epidural infusion of morphine and fentanyl

Respiratory effects, nausea, somnolence, and pruritus were compared during a 48-hr period of continuous epidural morphine (n = 34) and fentanyl (n = 32) infusion in 66 patients following elective total replacement of the hip or knee joint. Respiratory effects were assessed by PaCO2. Side effects were assessed by visual analogue scale and considered to be present when the score was above 30. Assessment was made at preoperative visits then 3, 6, 12, 24, 36, and 48 hr after the epidural injection. The bolus dose and subsequent infusion rate were 3,900 +/- 1,300 micrograms and 427 +/- 213 micrograms.hr-1 for morphine, and 85 +/- 46 micrograms and 56 +/- 27 micrograms.hr-1 for fentanyl. Pain relief was similar in both groups. In the morphine group, PaCO2 elevation and nausea occurred over a period of more than 12 hr (P less than 0.05). In the fentanyl group, there was no PaCO2 change, and nausea was confined to the first few hours. Nausea was more severe (P less than 0.01 at six hours and more frequent (24 hr cumulative incidence, 53 vs 28%, P less than 0.05) in the morphine group. Somnolence was prominent within several hours in two-thirds of patients in both groups. Somnolence continued to decline thereafter in the morphine group, but it was demonstrable in approximately half of the patients throughout the second day in the fentanyl group. The incidence was higher in the fentanyl group at the 48th hr (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Regional anaesthesia for hernia repair in children: local vs caudal anaesthesia

The purpose of this study was to compare the effect of local anaesthesia (LA) with that of caudal anaesthesia (CA) on postoperative care of children undergoing inguinal hernia repair. This was a randomized, single-blind investigation of 202 children aged 1–13 yr. Anaesthesia was induced with N₂O/O₂ and halothane or propofol and maintained with N₂O/O₂/halothane. Local anaesthesia included ilioinguinal and iliohypogastric nerve block plus subcutaneous injection by the surgeon of up to 0.3 ml · kg^?1 bupivacaine 0.25% with 5 μg · kg^?1 adrenaline. The dose for caudal anaesthesia was 1 ml · kg^?1 up to 20 ml bupivacaine 0.2% with 5 μg · kg^?1 adrenaline. Postoperative pain was assessed with mCHEOPS in the anaesthesia recovery room, with postoperative usage of opioid and acetaminophen in the hospital, and with parental assessment of pain with a VAS. Vomiting, time to first ambulation and first urination were recorded. The postoperative pain scores and opioid usage were similar; however, the LA-group required more acetaminophen in the Day Care Surgical Unit. The incidence of vomiting and the times to first ambulation and first urination were similar. The LA-patients had a shorter recovery room stay (40 ± 9 vs 45 ± 15 min, P < 0.02). The postoperative stay was prolonged in the CA group (176 ± 32 vs 165 ± 26 min, P = 0.02). We conclude that LA and CA have similar effects on postoperative care with only slight differences.     

Post-herniorrhaphy pain in outpatients after preincision ilioinguinal-hypogastric nerve block during monitored anaesthesia care

The objective of this study was to evaluate the effect of an ilioinguinal-hypogastric nerve block (IHNB) with bupivacaine 0.25% on the postoperative analgesic requirement and recovery profile in outpatients undergoing inguinal herniorrhaphy with local anaesthetic infiltration. Thirty consenting healthy men undergoing elective unilateral inguinal herniorrhaphy procedures were randomly assigned to receive an IHNB with either saline or bupivacaine according to a double-blind, IRB-approved protocol. All patients received midazolam, 2 mg iv, and fentanyl 25 μg iv, prior to injection of 30 ml of either bupivacaine 0.25% or saline through the oblique muscle approximately 1.5 cm medial to the anterior superior iliac spine. Subsequently, the surgeon infiltrated the incision site with a lidocaine 1% solution. Sedation was maintained during the operation with a variable-rate propofol infusion, 25–140 μg · kg^?1 · min^?1. No significant differences were noted in the intraoperative doses of lidocaine, propofol and fentanyl in the two treatment groups. However, the pain visual analogue score at 30 min after entering the PACU was lower in the bupivacaine (versus saline) group (P < 0.05). Although the times to ambulation (86 ± 18 vs 99 ± 27 min) and being judged “fit for discharge” (112 ± 49 vs 126 ± 30 min) were similar in the two groups, the bupivacaine-treated (vs saline) patients required less oral analgesic medication after discharge (46% vs 85%). We concluded that the use of an ilioinguinal-hypogastric nerve block with bupivacaine 0.25% as an adjuvant during inguinal herniorrhaphy under monitored anaesthesia care decreased pain in the PACU and oral analgesic requirements after discharge from the day-surgery unit.     

Low-dose sufentanil and lidocaine supplementation of general anaesthesia

This randomized double-blind study compared the effects of: (1) saline infusion (C); (2) sufentanil alone (1.0 micrograms.kg-1) (S); and (3) low-dose sufentanil (0.5 micrograms.kg-1) in combination with lidocaine (1.5 mg.kg-1) (LS): on the cardiovascular responses to tracheal intubation and on postoperative ventilation as monitored by respiratory inductive plethysmography in day-care surgical procedures of approximately 60 min duration. Thirty healthy, unpremedicated patients were studied. Thiopentone requirements were reduced by 40 and 28 per cent in the S and LS groups respectively compared with control (P less than 0.001). Both treatments suppressed HR and BP responses (P less than 0.005) to intubation. Postoperatively, PaCO2 was elevated (P less than 0.05) in group S. Dose-related respiratory depression was observed. The incidence of postoperative apnoea was significantly higher in both S and LS groups than compared with control (P less than 0.05). However, only patients in group S showed higher apnoea index and mean apnoea duration over the initial 10-20 min after surgery compared with control (P less than 0.005). In addition, group S showed slower respiratory frequency and prolonged expiratory time (P less than 0.005). In conclusion, an induction dose of sufentanil (1 microgram.kg-1) used in balanced anaesthesia of less than 70 min duration was associated with significant respiratory depression, particularly during the initial 10-20 min after surgery, whereas low-dose sufentanil (0.5 micrograms.kg-1) with lidocaine (1.5 mg.kg-1) had minimal postoperative respiratory depression and comparable attenuation of pressor responses to intubation.     

Induction reflex actions with intravenous nalbuphine as an adjunct to isoflurane

Ninety unpremedicated patients undergoing mask anaesthesia were assigned to one of three groups according to the volatile anaesthetic and the acute intravenous premedication administered. Group I received saline placebo as premedication and halothane by inhalation. Group II received saline placebo and isoflurane by inhalation. Group III received nalbuphine 0.1 mg.kg-1 IV as premedication and isoflurance by inhalation. Mean time to loss of consciousness (71 sec) did not differ among groups. The dosage of thiopentone required to induce loss of consciousness was decreased by 15 per cent (from 3.9 to 3.3 mg.kg-1) by nalbuphine premedication (P less than 0.05), and time to induction of surgical anaesthesia using isoflurane was decreased by 15 per cent (P less than 0.05). The incidence of reflex actions (coughing, laryngospasm, breath holding, hiccoughs and movement) during induction was no different in the saline-premedicated halothane or isoflurane groups. Acute intravenous nalbuphine premedication decreased significantly the incidence of reflex actions during induction of isoflurane anaesthesia from 77 per cent to 37 per cent (P less than 0.02). Desaturation episodes (SaO2 less than 90 per cent) were more frequent with isoflurane inductions compared with halothane (55 per cent vs 17 per cent, P less than 0.01). Apnoeic episodes accounted for the majority of desaturations associated with nalbuphine premedication, while excitatory reflexes (coughing and laryngospasm) accounted for more desaturations with isoflurane alone.     

Propofol anaesthesia reduces early post-operative emesis after paediatric strabismus surgery

Propofol anaesthesia may reduce postoperative emesis. The purpose of this study was to compare the incidence of emesis after propofol anaesthesia with and without nitrous oxide, compared with thiopentone and halothane anaesthesia, in hospital and up to 24 hr postoperatively, in outpatient paediatric patients after strabismus surgery. Seventy-five ASA class I or II, unpremedicated patients, aged 2–12 yr were randomly assigned to one of three groups: Thiopentone, 6.0 mg · kg^{? 1} iv induction followed by halothane and N₂O/O₂ for maintenance (T/H); propofol for induction, followed by propofol and oxygen for maintenance (P/O₂); and propofol for iv induction, followed by propofol infusion and N₂O/O₂ for maintenance (P/N₂O). All received vecuronium, controlled ventilation, and acetaminophen pr. Morphine was given as needed for postoperative analgesia. There were no differences in age, weight, number of eye muscles operated upon, duration of anaesthesia or surgery. The P/N₂O group (255 ± 80 μg· kg^{? 1}· min^{? 1}) received less propofol than the P/O₂ group (344 ± 60 μg · kg^{? 1}· min^{? 1}) (P ≤ 0.0001) and had shorter extubation (P < 0.001) and recovery (P < 0.01) times. Emesis in the hospital, in both the P/N₂O (4.0%) and P/O₂ group (4.0%) was less than in the T/H group (32%) (P < 0.01). Antiemetics were required in four patients in the T/H group (16.0%). Overall emesis after surgery was not different among the groups: T/H (48%), P/O₂ (28%) and P/N₂O (42%). The use of propofol anaesthesia with and without N₂O decreased only early emesis. This supports the concept of a short-acting, specific antiemetic effect of propofol.