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.     

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.     

A comparison of fentanyl,esmolol, and their combination for blunting the haemodynamic responses during rapid-sequence induction

The purpose of this randomized, double-blind study was to compare the ability of a combination of fentanyl and esmolol to blunt the haemodynamic effects of intubation with that of either agent alone. Patients received fentanyl or saline four minutes before, and esmolol or saline two minutes before rapid-sequence induction of anaesthesia. The F2 group (n = 24) received fentanyl 2 micrograms.kg-1, the E2 group (n = 24) received esmolol 2 mg.kg-1, the F2/E2 group (n = 25) received a combination of fentanyl 2 micrograms.kg-1 and esmolol 2 mg.kg-1, and the F5 group (n = 26) received fentanyl 5 micrograms.kg-1. Following tracheal intubation, the maximum percent change from baseline heart rate was less in the F2/E2 and F5 groups (12% and 16% respectively) than in the E2 group (34%)(P < 0.05). The maximum percent changes from baseline systolic blood pressure in the F2/E2 and F5 groups (15% and 6% respectively) were less than in the F2 and E2 groups (24% and 33% respectively) (P < 0.05). The combination of a low dose of fentanyl and esmolol provides an alternative to a higher dose of fentanyl for blunting the haemodynamic responses to laryngoscopy and tracheal intubation during rapid-sequence induction in healthy patients.     

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.     

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.     

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.     

Bolus doses of esmolol for the prevention of perioperative hyper-tension and tachycardia

The effectiveness of esmolol, an ultra short-acting cardioselective beta blocker, in the prevention and treatment of post-intubation haemodynamic perturbations, was investigated. Forty-eight ASA physical status I and II patients undergoing hysterectomy were randomly assigned to receive a single intravenous bolus of placebo, esmolol 100 mg, or esmolol 200 mg in a double-blind fashion. This was administered over 15 sec, and immediately followed by thiopentone 3-5 mg.kg-1, succinylcholine 1.5 mg.kg-1, and tracheal intubation 90 sec later. The heart rate following induction of anaesthesia was lower in the esmolol 200 mg group (P less than 0.01); following intubation, the increase in heart rate in the placebo group was greater than in the esmolol groups (P less than 0.05). The systolic blood pressure post-induction was lower in the esmolol 200 mg group (P less than 0.05); following intubation, however, no significant differences were seen among groups in systolic, diastolic, or mean blood pressures. Following tracheal intubation, the incidence of ventricular arrhythmias was lower in the esmolol groups (P less than 0.05). In summary, esmolol in 100 mg and 200 mg doses was effective in mitigating the haemodynamic response following tracheal intubation.     

Atropine-induced heart rate changes: a comparison between midazolam-fentanyl-propofol-N2O and midazolam-fentanyl-thiopentone-enflurane-N2O anaesthesia

Atropine-induced heart rate (HR) changes were studied in 19 patients (ASA physical status I) during anaesthesia maintained predominantly with propofol-N₂O or thiopentone-enflurane-N₂O. Ten patients (Group A) received midazolam (0.07 mg · kg^?1), fentanyl (1 μg · kg^?1), propofol (2 mg · kg^?1) and succinylcholine (1 mg · kg^?1). Following tracheal intubation, anaesthesia was maintained with propofol (6 mg · kg^?1 · hr^?1), N₂O (67 per cent) and O₂ (33 per cent). In nine patients (Group B) thiopentone (4 mg · kg^?1) was substituted for propofol and anaesthesia maintained with N₂O (67 per cent) O₂ (33 per cent), and enflurane (0.5 per cent inspired concentration). The study was non-randomised because Group B patients were only included if HR before administration of atropine < 90 beats · min^?1. IPPV was performed in all patients using a Manley ventilator (minute vol. 85 ml · kg^?1; tidal vol. 7 ml · kg^?1). Ten minutes after tracheal intubation, incremental doses of atropine (equivalent cumulative doses: 1.8, 3.6, 7.2, 14.4, 28.8 μg · kg^?1) were administered at two-minute intervals and HR responses calculated during the last 45 sec of each intervening period. No differences were observed between the groups following 1.8 and 3.6 μg · kg^?1 atropine, but propofol-N₂O anaesthesia was associated with reduced responses (P < 0.01) following 7.2, 14.4 and 28.8 μg · kg^?1 atropine. These results suggest that there is a predominance of parasympathetic influences during propofol-N₂O anaesthesia compared with thiopentone-enflurane-N₂O anaesthesia.     

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.     

Neuromuscular and cardiovascular effects of mivacurium chloride in surgical patients receiving nitrous oxide-narcotic or nitrous oxide-isoflurane anaesthesia

The neuromuscular and cardiovascular effects of mivacurium chloride were studied during nitrous oxide-oxygen narcotic (fentanyl) (n = 90) and nitrous oxide-oxygen isoflurane (ISO) anaesthesia (n = 45). In addition, a separate group (n = 9) received succinylcholine during fentanyl anaesthesia to compare its neuromuscular effects with mivacurium. Mivacurium was initially administered as a single bolus in doses from 0.03 mg.kg-1 to 0.25 mg.kg-1 to study the dose-response relationships, as well as the cardiovascular effects of mivacurium. Neuromuscular block (NMB) was measured by recording the twitch response of the adductor pollicis muscle following ulnar nerve stimulation (0.15 Hz, 0.2 ms supramaximal voltage). The ED95 values for mivacurium were estimated to be 0.073 mg.kg-1 and 0.053 mg.kg-1 in the fentanyl and ISO groups respectively. The duration of block (time from injection to 95 per cent recovery) for a dose of 0.05 mg.kg-1 mivacurium was 15.3 +/- 1.0 min and 21.5 +/- 1.3 min for fentanyl and ISO anaesthesia, respectively. The recovery index (25-75 per cent) between initial bolus dose (6.1 +/- 0.5 min), repeat bolus doses (7.6 +/- 0.6 min), mivacurium infusion (6.7 +/- 0.7 min) and succinylcholine infusion (6.8 +/- 1.8 min) were not significantly different. There was minimal change in mean arterial pressure (MAP) or heart rate (HR) following bolus doses of mivacurium up to 0.15 mg.kg-1. Bolus administration of 0.20 mg.kg-1 or 0.25 mg.kg-1 of mivacurium decreased MAP from 78.2 +/- 2.5 to 64.0 +/- 3.2 mmHg (range 12-59 per cent of control) (P less than 0.05). The same doses when administered slowly over 30 sec produced minimal change in MAP or HR.     

Haemodynamic interactions of muscle relaxants and sufentanil in coronary artery surgery

The haemodynamic interactions between sufentanil (S) and muscle relaxants (MR) were studied in 40 ASA physical status III or IV patients (four groups of ten) scheduled for coronary artery bypass grafting (ABG). Group I received pancuronium (P) 0.08 mg.kg-1, Group II received vecuronium (V) 0.1 mg.kg-1, Group III received atracurium (A) 0.5 mg.kg-1 and Group IV metocurine 0.1 mg.kg-1 plus pancuronium 0.02 mg.kg-1 (M-P). Sufentanil, 20 micrograms.kg-1 was administered before sternotomy, 10 micrograms.kg-1 being injected before tracheal intubation and 10 micrograms.kg-1 afterwards. Heart rate (HR), ECG leadII and V5, systolic, diastolic and mean arterial and pulmonary blood pressures, central venous pressure (CVP) and pulmonary capillary wedge pressure (W) were measured and recorded at the time of seven strategic events between the pre-induction of anaesthesia period and sternotomy. Cardiac output (CO) and systemic vascular resistances (SVR) were also measured before induction of anaesthesia and after the administration of S 10 micrograms.kg-1 plus the MR. The HR decreased from baseline values in the post-tracheal intubation period in all groups except in P group. The mean arterial pressure also decreased significantly in all groups except in the P group. The CO did not change from baseline values but SVR decreased in all groups. There was no evidence of new myocardial ischaemia according to the ECG monitoring and there was no significant difference in the HR changes between patients who had or who had not received beta-blockers in any group. We conclude that within the present study conditions and design, HR and blood pressure changed least with pancuronium.     

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.     

Comparative evaluation of propofol and thiopentone for total intravenous anaesthesia

Sixty unpremedicated ASA physical status I or II patients scheduled for surgical procedures of intermediate duration (15 to 60 min) were studied to evaluate the safety and efficacy of propofol, to measure recovery times and to compare the return of psychomotor and cognitive function with thiopentone. Patients were randomly allocated into two groups. Anaesthesia was induced and maintained by either propofol (2.0-2.5 mg.kg-1 followed by a continuous infusion 0.1-0.2 mg.kg-1.min-1) or thiopentone (4.0-5.0 mg.kg-1, and infusion rate 0.16-0.32 mg.kg-1.min-1), titrated to patient response. Succinylcholine was administered to facilitate tracheal intubation and maintain neuromuscular blockade. Induction of anaesthesia was slightly longer with propofol than thiopentone (42.2 vs 29.8 sec) and was smooth with both drugs. Post-intubation increases in heart rate, and systolic and diastolic blood pressures were attenuated by propofol when compared with thiopentone. After the administration of propofol, times to eye opening (6.4 +/- 4.3 vs 13.9 +/- 15.9 min), response to verbal command (7.6 +/- 6.3 vs 15.4 +/- 16.6 min) and orientation (22.7 +/- 12.8 vs 36.2 +/- 23.1 min), were significantly shorter. Psychomotor and cognitive function returned earlier with propofol and fewer side effects were noted. At 24 hr there was no distinguishable difference between groups. Propofol is a safe anaesthetic agent with the potential for early patient discharge and street fitness after outpatient procedures.     

Tussive effect of a fentanyl bolus

The aim of this study was to investigate the incidence of pre-induction coughing, after an iv bolus of fentanyl. The study sample was 250 ASA physical status I-II patients, scheduled for various elective surgical procedures. The first 100 were randomly allocated to receive 1.5 micrograms.kg-1 fentanyl via a peripheral venous cannula (Group 1), or an equivalent volume of saline (Group 2). Twenty-eight per cent of patients who received fentanyl, but none given saline, coughed within one minute (P less than 0.0001). The second 150 patients were then randomly assigned to three equal pretreatment groups. Group 3 received 0.01 mg.kg-1 atropine iv one minute before fentanyl. Groups 4 and 5 received 0.2 mg.kg-1 morphine im, and 7.5 mg midazolam po, respectively, one hour before fentanyl. Thirty per cent of patients in Group 3, 6% in Group 4, and 40% in Group 5, had a cough response to fentanyl. Fentanyl, when given through a peripheral cannula, provoked cough in a considerable proportion of patients. This was not altered by premedication with atropine or midazolam, but was reduced after morphine (P less than 0.01). Coughing upon induction of anaesthesia is undesirable in some patients, and stimulation of cough by fentanyl in unpremedicated patients may be of clinical importance.     

Postoperative neuromuscular block following atracurium or alcuronium in children

Postoperative neuromuscular block (NMB) was evaluated in 60 children who received randomly either atracurium or alcuronium to induce and maintain an 85-95 per cent NMB during balanced anaesthesia. The EMG-monitor was turned away from the anaesthetist 10-15 min before the end of surgery. The average NMB was comparable between the groups at the time of reversal with neostigmine 50 micrograms.kg-1 (84 +/- 9 per cent, mean +/- SD) as were the NMB and the train-of-four ratio when the tracheas were extubated on a clinical basis (32 +/- 20 per cent and 50 +/- 18 per cent, respectively). Patients who had been paralyzed with atracurium arrived at the recovery room earlier and on arrival had greater train-of-four ratios than the patients paralyzed with alcuronium (P less than 0.01). Time to a train-of-four ratio of greater than 90 per cent was significantly shorter in the atracurium group (10 +/- 5 min vs 26 +/- 15 min, P less than 0.001). Thus, an intermediate-acting muscle relaxant offers a safer recovery profile of the NMB than a long-acting muscle relaxant in paediatric patients.     

A comparison of spinal and epidural anaesthesia for hip arthroplasty

Spinal and epidural anaesthesia were compared in 65 patients undergoing hip arthroplasty, with regard to the degree of sensory and motor blockade, cardiovascular effects, operating conditions, the dose of propofol required to produce satisfactory hypnosis, and complications. Epidural anaesthesia was successful in 30 patients using an initial dose of 15 ml of 0.5% bupivacaine, and spinal anaesthesia in 32 patients, using 4 ml 0.5% isobaric bupivacaine. The two techniques were similar with regard to the level of sensory blockade (T8), degree of hypotension and perioperative haemorrhage. Differences occurred in the degree of motor blockade (mean Bromage score of 1 in the spinal group vs 3.86 in the epidural group) (P less than 0.05), time to achieve maximal cephalad spread (13 min in the spinal group vs 21 min in the epidural group) (P less than 0.05) and the dose of propofol required to produce adequate hypnosis (1.95 mg.kg-1.hr-1 in the spinal group vs 2.89 mg.kg-1.hr-1 in the epidural group) (P less than 0.05). Only seven patients required urethral catheterization in this spinal group compared with 14 in the epidural group (P less than 0.05). Spinal anaesthesia also proved advantageous by providing better operating conditions for the surgeon, with a lower incidence of patient movement.     

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.     

Elective oral tracheal intubation in cervical spine-injured adults

There is controversy regarding the optimal mode of elective tracheal intubation in the patient with an unstable cervical spine following trauma. A ten-year review of 150 patients with traumatic cervical spine injuries with well-preserved neurological function, presenting for operative stabilization, was conducted to compare neurological outcome with the mode of tracheal intubation. Preoperative neurological deficits were identified in 49 patients (33%); most were single-level radiculopathies. Intubation occurred after induction of general anaesthesia in 83 patients (55%) and in 67 patients (45%) the tracheas were intubated with the patient awake. One hundred and six patients (71%) underwent oral tracheal intubation and 44 underwent nasal tracheal intubation. Ten intubations were deemed to be difficult requiring more than one attempt to effect intubation. Cervical spine immobilization during intubation was documented in 86 patients (57%). Weighted traction or manual in-line traction were the two manoeuvres most commonly employed to maintain spinal alignment during intubation. After surgery, two patients had new neurological deficits. There were no differences in neurological outcome whether intubation was performed while the patient was awake or under general anaesthesia, or comparing oral tracheal intubation with all other techniques (P = 0.5, Fisher exact test). Also, in-line traction did not affect neurological outcome. Oral tracheal intubation with in-line stabilization, either performed after induction of general anaesthesia or with the patient awake, remains an excellent option for elective airway management in patients with cervical spine injuries.     

Esmolol bolus and infusion attenuates increases in blood pressure and heart rate during electro-convulsive therapy

To determine whether a standardized dose of esmolol can effectively attenuate the cardiovascular response to electroconvulsive therapy (ECT), 17 ASA physical status I-II patients were studied in a randomized within-patient, crossover design. Each patient received "no esmolol" during one ECT and three to five days later crossed over to the alternative treatment receiving an esmolol 80 mg bolus followed by 24 mg.min-1 infusion two minutes prior to induction of anaesthesia and continued for five minutes after induction. Esmolol blunted the maximum increases in heart rate (HR) by 26 per cent, mean arterial pressure (MAP) by 14 per cent, and rate pressure product by 37 per cent with significant differences (P less than 0.05) noted at one, two, three and four minutes after ECT (minutes five, six, seven, and eight of the esmolol infusion). There was no significant difference in seizure duration between the two groups and no adverse reactions occurred.     

Onset of vecuronium neuromuscular block is more rapid in patients undergoing Caesarean section

This investigation was carried out in ten patients undergoing elective Caesarean section and the results were compared with those of a control group of ten nonpregnant females of the same age group. The study investigated the onset of vecuronium neuromuscular block and the conditions of tracheal intubation when ketamine (1.5 mg.kg-1)-vecuronium 100 micrograms.kg-1) sequence was used for rapid-sequence induction of anaesthesia. The ulnar nerve was stimulated supra-maximally at the wrist with train-of-four stimuli every 20 sec, and the electromyographic response of the adductor pollicis muscle was displayed. The onset of 50% neuromuscular block as monitored by electromyography was shorter in the Caesarean group (80 +/- 30 sec) than in the control group (144 +/- 43 sec). The conditions of intubation at 50% block were adequate in both groups. Also, the onset of 90% block was shorter in the Caesarean group. The time of recovery to T1/control ratio of 25% was longer in the Caesarean group (46 +/- 10 min) than in the control patients (28 +/- 10 min). The results show that administration of vecuronium according to body weight results in a more rapid onset and delayed recovery of neuromuscular block in pregnant women undergoing Caesarean section than in the nonpregnant control patients.