Pharmacokinetics of two per cent rectal methohexitone in children

Plasma methohexitone concentrations were determined in 60 children, aged one to six years, following administration of 15 mg.kg-1, 20 mg.kg-1, 25 mg.kg-1 or 30 mg.kg-1 two per cent rectal methohexitone. Time to the onset of sleep was determined by a blinded observer and venous blood samples obtained 15, 30, 45 and 120 minutes following drug administration. Fifty of 60 children were asleep within 15 minutes. Nine of the ten children that did not fall asleep were sedate and could be separated easily from their parents to undergo inhalational induction of anesthesia. Time to the onset of sleep was inversely related to the dose of rectal methohexitone administered. Sleep was achieved more reliably following the use of 25 to 30 mg.kg-1 rectal methohexitone. In addition, plasma methohexitone concentrations following 30 mg.kg-1 rectal methohexitone were significantly higher for up to 120 minutes following drug administration than the plasma concentrations achieved after 15 mg.kg-1 or 20 mg.kg-1 methohexitone. There was no difference in the incidence of complications. The authors recommend that clinical circumstances be carefully considered and the dose of rectal methohexitone administered be individualized to meet the specific anaesthetic requirements of each child.     

Comparison of induction characteristics of four intravenous anaesthetic agents

The induction characteristics of thiopentone, etomidate and methohexitone have been compared to those of propofol (2,6 di-isopropyl phenol) in unpremedicated patients. Propofol 2.5 mg/kg caused significantly more hypotension, excitatory side effects and pain on injection at the dorsum of hand than thiopentone 5 mg/kg. However, with regard to the latter two sequelae, etomidate 0.3 mg/kg and methohexitone 1.5 mg/kg caused similar or more frequent upset. Propofol 2.0 mg/kg was equipotent with thiopentone 4.0 mg/kg in terms of successful induction of anaesthesia. Hypotension may contraindicate the use of propofol in the hypovolaemic or unfit patient.     

Comparison of propofol induction with thiopentone or methohexitone in short outpatient general anaesthesia

The per- and post-operative characteristics of three different i.v. anaesthetic induction agents were studied double-blindly in 75 patients admitted for outpatient gynaecological dilatation and curettage. All the patients were premedicated with midazolam 0.1 mg/kg i.m. Induction started with alfentanil 0.015 mg/kg i.v. 60 s before either: propofol 2.2 mg/kg i.v., or thiopentone 4.0 mg/kg i.v., or methohexitone 2.0 mg/kg i.v. All the patients received 66% nitrous oxide in oxygen. The propofol patients were significantly better relaxed and had a higher incidence of hypotension during the procedure. The methohexitone patients had higher pulse rates and a higher frequency of hiccups during the procedure. Propofol induction resulted in a faster awakening of the patients and a better recovery function compared with methohexitone for the first 15 min and compared with thiopentone for the first 240 min after the procedure. Postoperative side-effects were less frequent in the thiopentone group, and minor abdominal pain was significantly more frequent in the propofol group. There was no significant difference between the groups for any variable after 240 min postoperatively.     

Propofol and alfentanil infusion

In 42 patients undergoing major surgery, anaesthesia was induced by intravenous alfentanil 10 micrograms/kg together with methohexitone 1.5 mg/kg or propofol 2 mg/kg. An infusion of six times these doses per hour was then started; the rate was varied subsequently as indicated by the monitoring of arterial blood pressure, heart rate, EEG and frontalis electromyogram. The mean duration of infusion was 76.7 minutes for propofol and 74.5 minutes for methohexitone and the infusion was stopped about 10 minutes before the end of surgery in each group. The induction dose differed, but the total dose requirement for the two drugs was similar. In every case, anaesthesia was satisfactory. Methohexitone caused a significant rise in mean pulse rate throughout anaesthesia (p less than 0.05, paired t-test). There was no change in mean pulse rate during propofol infusion. The dose of alfentanil used provided excellent control of autonomic reflexes, with negligible respiratory depression. Naloxone was not required. Propofol provided better anaesthesia than methohexitone, with fewer side effects (p less than 0.05, Chi squared test), easier control of the level of narcosis and faster recovery (p less than 0.001, t-test after log transformation).     

Recovery times following induction of anaesthesia with propofol, methohexitone, enflurane or thiopentone in children

We have measured the times to early recovery in forty children aged 3-14 years in whom anaesthesia was induced by intravenous propofol, methohexitone, thiopentone or inhalation of enflurane. Maintenance anaesthesia consisted of inhalation of nitrous oxide, oxygen and enflurane via a face mask. Early recovery, assessed by the Steward recovery score, was significantly faster after propofol, methohexitone or inhalation of enflurane compared with thiopentone (P < 0.01). There were no significant differences in recovery times between propofol, methohexitone or enflurane. We conclude that the use of propofol to induce anaesthesia does not hasten recovery in children undergoing short day-case procedures compared with methohexitone or inhalation of enflurane.     

One lung high frequency ventilation for peroral sealing of bronchial stump fistulae

The use of high frequency ventilation for 28 repairs of bronchial stump fistulae with fibrin sealant is discussed. Intravenous anaesthesia with continuous infusions of methohexitone, alfentanil and suxamethonium was employed. This method of anaesthesia and ventilation proved to be satisfactory.     

Etomidate and methohexitone

Etomidate compares favourably with methohexitone as an intravenous induction agent in out-patient anaesthesia excluding the incidence of involuntary muscle movement. The use of propylene glycol as a solvent for etomidate does not alter the previously claimed advantageous features of this agent.     

Comparison of two and ten per cent rectal methohexitone for induction of anaesthesia in children

Plasma methohexitone concentrations were determined in 30 children, aged one to six years, who received 25 mg.kg-1 rectal methohexitone as either a two per cent or ten per cent solution for induction of anaesthesia. Venous blood samples were obtained 15, 30, 45 and 120 minutes following drug administration. Twenty-six of 30 children were asleep within fifteen minutes. Mean plasma methohexitone concentrations were 5.39, 4.42, 3.40 and 1.54 micrograms.ml-1 at 15, 30, 45 and 120 minutes following administration of two per cent methohexitone. Use of the ten per cent solution resulted in mean plasma methohexitone concentrations of 3.81, 3.12, 2.31 and 1.07 micrograms.ml-1 at the same time intervals. Plasma methohexitone concentrations were significantly higher at 15, 30 and 45 minutes following administration of two per cent methohexitone, when compared to the ten per cent solution.