Cuffed oropharyngeal airway (COPA) as an adjunct to fibreoptic tracheal intubation.

The cuffed oropharyngeal airway (COPA) was evaluated as an adjunct to oral and nasal fibreoptic tracheal intubation in 40 adult patients during general anaesthesia. Time from start to completion of intubation decreased rapidly with experience (median time 138 s). We conclude that the COPA may be a useful adjunct to fibreoptic tracheal intubation, allowing control and support of the airway during the procedure, using various anaesthetic techniques, in an acceptable amount of time. The ability to perform fibreoptic tracheal intubation while effectively supporting the airway using the COPA may be advantageous in managing the difficult airway and in trainee education.

The cuffed oropharyngeal airway as an aid to fibreoptic intubation.

The cuffed oropharyngeal airway is a new disposable airway based on the Guedel oral airway. It has an asymmetrical cuff which provides a seal as well as lifting the base of the tongue forwards, and a 15-mm connector allowing attachment to an anaesthetic breathing system. The device does not extend beyond the vallecula, so that the laryngeal inlet can be visualised with a fibreoptic laryngoscope passed between the cuff of the device and the pharyngeal wall. The advantage is that ventilation is maintained throughout the intubating sequence. We describe its use in a patient with oropharyngeal carcinoma.

The morphine sparing effect of diclofenac sodium following caesarean section under spinal anaesthesia.

We have studied the morphine sparing effect of a single 100 mg diclofenac sodium suppository following elective caesarean section performed under spinal anaesthesia. Fifty patients randomly allocated into a placebo or an active group were compared. There was a statistically significant (P < 0.05) reduction in total morphine consumption and in consumption calculated as mg kg h(-1) in the diclofenac group, although pain scores were comparable in the two groups.

Epidural diamorphine for post-caesarean pain: a dose response study.

The effectiveness of postoperative pain relief and the frequency of side effects with three different doses of epidural diamorphine (2.0, 3.5 and 5 mg) was investigated. The study was carried out double-blind in 30 women undergoing awake elective caesarean section. Postoperative pain intensity was measured on a linear analogue scale. The time to onset of analgesia (TOA), time taken to reach a pain score of zero or become comfortable, and time to next analgesia (TNA) were not significantly different between groups. Three patients in the 2 mg group failed to achieve scores of zero but were comfortable. No nausea or vomiting was seen but the incidence of itching was 0, 30% and 80% in the 2.0, 3.5 and 5 mg groups respectively. We conclude that epidural diamorphine 2 mg is adequate for relief of post-caesarean pain and higher doses may increase the incidence of unwanted side-effects.

Intrathecal morphine for post caesarean section analgesia: does naloxone reduce the incidence of pruritus?

Good quality, long lasting pain relief can be achieved with intrathecal opiates, but often at the expense of pruritus, nausea and vomiting. Two groups of patients undergoing caesarean section under spinal anaesthesia with heavy bupivacaine 0.5% plus 0.2 mg preservative-free intrathecal morphine were studied. Patients were randomly selected to receive an infusion of dextrose saline with or without naloxone at 0.1 mg/h (over 8 h) after delivery of the baby and were studied for 24 h to assess analgesic requirements and side-effects. There was a significant reduction in the frequency and severity of pruritus in the naloxone group while the infusion was running, but pain relief was not impaired.

Infusions of propofol to supplement nitrous oxide-oxygen for the maintenance of anaesthesia. A comparison with halothane.

The peri-operative and postoperative effects of propofol given by infusion were compared with halothane as a supplement to nitrous oxide-oxygen anaesthesia for body surface surgery in patients who breathed spontaneously. Anaesthesia was induced after opioid premedication, with either propofol 2.5 mg/kg or thiopentone 4-5 mg/kg which were followed respectively by an infusion of propofol 12 mg/kg/hour for 10 minutes and at a variable rate thereafter, or by halothane at a mean inspired concentration of 1.2%. Maintenance of anaesthesia required a median rate of infusion of propofol of 149.4 micrograms/kg/minute. The cardiovascular effects during induction and maintenance of anaesthesia were similar in the two groups. The overall incidence of side effects was low but immediate recovery was significantly faster in patients who received propofol.

Disposition of propofol in patients undergoing surgery. A comparison in men and women.

The disposition kinetics of propofol have been determined in 12 patients (six female) receiving propofol 2.5 mg kg-1 for induction of anaesthesia, which was maintained with 67% nitrous oxide in oxygen and 1-1.5% halothane. Peripheral blood samples were collected at selected times up to 8 h after the injection of the drug, and whole blood propofol concentrations determined by HPLC with fluorescence detection. Drug concentration-time data were analysed by the non-linear regression program ELSFIT. This showed the data to be describable by a tri-exponential equation, corresponding to a three-compartment model. There were no differences in the derived kinetic indices for the male and female patients, with the exception of a greater Vdss:V gamma ratio in the males. The terminal half-life in the male patients was 262 min (SEM 44), and in the female patients 309 min (60). Vdss was 329 litre (67) and 313 litre (69) in male and female patients, respectively. The clearance in both groups was 1.8 litre min-1. Seven out of 12 patients showed significant secondary peaks in blood propofol concentration associated with recovery from anaesthesia.

Effects of diazepam and midazolam on recovery from anaesthesia in outpatients.

Sixty patients were randomly allocated in an open study to receive either midazolam or diazepam (Diazemuls) with fentanyl and etomidate for induction and maintenance of anaesthesia during day-stay gynaecological surgery. The excitatory effects of etomidate were controlled by the benzodiazepine-fentanyl combination in both groups. No significant difference in the quality of recovery (as judged by Trieger test analysis), amnesia, incidence of recall of pain on injection of etomidate or nausea and vomiting could be demonstrated between the groups. There was a high degree (97%) of patient acceptance.

Use of an emulsion of ICI 35868 (propofol) for the induction and maintenance of anaesthesia.

2,6-Diisopropyl phenol in a fat emulsion formulation (propofol) has been used to supplement 67% nitrous oxide in oxygen anaesthesia in 20 patients premedicated with morphine 0.15 mg kg-1 and atropine 0.6 mg, and undergoing body surface surgery. Following an induction dose of propofol 2.5 mg kg-1, the mean maintenance dose was 73.4 micrograms kg-1 min-1. When compared with 10 patients receiving Althesin to supplement nitrous oxide in oxygen in a similar manner, recovery was considerably faster following propofol. The only major side-effect associated with the use of propofol was pain on injection in nine out of 20 patients. When the patients receiving propofol were compared with a second control group (n = 11) in whom anaesthesia was induced with thiopentone 4 mg kg-1 and maintained with 1% halothane and nitrous oxide in oxygen, the former group showed a significant (P less than 0.01) decrease in the plasma cortisol concentration 30 min after the induction of anaesthesia. However, by 3 h after induction, the cortisol concentration in both groups was not significantly different from the baseline (preinduction) value. The mechanism of this decrease is not known. Investigation of the influence of the fat emulsion on blood coagulation and fibrinolysis revealed no differences when compared with patients receiving Althesin.

Influence of meptazinol on metabolic and hormonal responses following major surgery. A comparison with morphine.

Opioid drugs in high doses can obtund the stress response to major surgery but only at the expense of marked cardiorespiratory depression. The postoperative hormonal response to surgical stress was measured in 20 patients undergoing hysterectomy who were given either meptazinol 100 mg or morphine 15 mg intramuscularly at the end of the surgery. Both drugs at the doses used failed to diminish the stress response. Those patients who received meptazinol showed elevated prolactin levels: this may be an indicator of agonist activity at the mu 1 opioid receptor.

Haematological and biochemical changes during anaesthesia with propofol ('Diprivan').

The influence of an emulsion formulation of 2,6-diisopropylphenol (propofol) on blood coagulation and fibrinolysis, and on the neuroendocrine responses to surgery has been investigated in 12 patients who received incremental doses of propofol to supplement 67% nitrous oxide in oxygen as anaesthesia for body surface surgery. The effects were compared with those in 10 patients who received Althesin to supplement nitrous oxide in oxygen in a similar manner. When pre-operative values were compared with data obtained after 30 min surgery, no significant effects on coagulation or fibrinolytic indices were found in either group. Both groups, however, showed a significant fall in haemoglobin concentration 30 min after induction of anaesthesia (P less than 0.05); and a fall in haematrocrit value was observed in those patients who received propofol (P less than 0.05). No changes in total white cell counts or platelet counts were observed. Both groups of patients showed a significant rise in blood glucose 30 min after induction of anaesthesia (P less than 0.001). After 3 h values were not significantly different from preoperative levels. The mean plasma cortisol levels fell in both groups 30 min after induction of anaesthesia, but returned to control values by 3 h. The mechanism causing this decrease is not known.

Pharmacokinetics of propofol ('Diprivan') as an induction agent.

The disposition kinetics of propofol have been determined in 12 patients (6 female) receiving 2.5 mg/kg for induction of anaesthesia which was maintained using 1.5% halothane and 67% nitrous oxide in oxygen. Patients were premedicated with oral diazepam 10 mg and were undergoing body surface surgery. Peripheral venous samples were collected up to 8 h after injection of the drug. Whole blood propofol concentrations were determined by high pressure liquid chromatography using fluorescence detection. Data analysis indicates a 3 compartment model, with a terminal half-life of 286 (s.e.m. +/- 36) min, clearance of 1803 +/- 125 ml/min, and volume of distribution of 755 +/- 109 litres. These values are significantly different from those reported previously by Adam et al., (1983) for the Cremophor formulation of the drug. Seven of the patients showed significant secondary peaks of the blood concentration associated with recovery from anaesthesia.

Propofol ('Diprivan') as a supplement to nitrous oxide-oxygen for the maintenance of anaesthesia.

Incremental doses of propofol (10-20 mg) have been used to supplement nitrous oxide in oxygen anaesthesia for patients undergoing body surface surgery. After premedication with morphine 0.15 mg/kg, anaesthesia was successfully induced in 21 patients with 2.5 mg/kg propofol. One patient with labile hypertension suffered a pronounced cardiovascular response to the induction of anaesthesia, but without operative sequelae. The mean maintenance rate of propofol was 73.4 micrograms/kg/min. When compared with 10 patients receiving incremental doses of Althesin, recovery to giving correct date of birth was significantly faster in patients receiving propofol (P less than 0.01); when compared with 11 patients receiving an induction of thiopentone 5 mg/kg and nitrous oxide/oxygen/halothane, more patients receiving propofol had recovered to giving correct date of birth by 10 min after the end of anaesthesia (P less than 0.001). However, use of propofol was associated with pain on injection in 9 out of 20 patients, and apnoea of greater than 30 s in 8 patients.

Dose requirements of ICI 35,868 (propofol, 'Diprivan') in a new formulation for induction of anaesthesia.

In order to avoid Cremophor-related reactions and reduce the incidence of pain on injection, diisopropylphenol (ICI 35,868; propofol) has been reformulated as an emulsion. One hundred and fifteen patients received an induction dose of propofol in the new formulation. The dose required to induce anaesthesia in 95% of healthy, unpremedicated patients was 2.5 mg/kg. Induction was associated with a degree of cardiovascular and respiratory depression. There were no adverse reactions although there were a number of minor side-effects. The incidence of pain on injection was low (3%) and the overall quality of induction was assessed as good or adequate in 92% of patients.

Premedication with butorphanol. A comparison with morphine.

A blind comparison was made of butorphanol 2 mg with morphine 10 mg i.m. as the sole premedication in four groups, each of 10 women, undergoing total abdominal hysterectomy. On both subjective and objective grounds, butorphanol was as effective as morphine with the advantage of fewer unwanted side-effects, although one patient complained of hallucinations. No clinically significant antagonism could be demonstrated between butorphanol and fentanyl. One patient gave accurate recall of intraoperative events, which reflects the problem of designing a properly constructed scoring system, based on basic clinical signs, to predict accurately the adequacy of anaesthesia.