General anaesthesia with intravenous flunitrazepam, continuous ketamine infusion and muscle relaxant. A preliminary report.

We present a preliminary report of an anaesthetic technique for abdominal surgery involving a combination of flunitrazepam induction and continuous ketamine maintenance of anaesthesia, specifically avoiding the use of any inhalational agents. Standard techniques of muscle relaxation, intubation and ventilation with oxygen-enriched air were employed.

Anaesthetic induction for caesarean section with etomidate compared with thiopentone.

Anaesthesia for caesarean section demands a technique that provides perfect narcosis without neonatal depression. To date, no ideal induction agent has been found for obstetric anaesthesia, although thiopentone is still considered the safest. A new agent, etomidate (0,3 mg/kg) has been studied in a group of parturients who underwent elective caesarean section in the left lateral tilt position. The results obtained are compared with those from a similar series, in which the management was identical, except that anaesthesia was induced with thiopentone 3,5 mg/kg. The infants in the present series were usually extremely lively after delivery, and generally sustained respiration in a shorter time than those after thiopentone. In addition, maternal-to-fetal base excess gradients were narrower with etomidate than with thiopentone. Thus etomidate may offer some advantage over thiopentone for anaesthetic induction at elective caesarean section, and appears worthy of further trial.

Anaesthesia for caesarean section. An updated review of its special problems and their management.

We have attempted to update a previous review of the hazards and problems confronting the mother, fetus and anaesthetist at caesarean section. A recent survey of obstetric anaesthesia within the Republic and South West Africa indicates that a significant proportion of anaesthetic services for midwifery are provided by non-specialist practitioners in hospitals outside major population centres. We believe that both mothers and their infants will gain from the careful perusal by their doctors of this review.

A survey of obstetric anaesthesia in the Republic of South Africa and South West Africa.

In this report we analyse the results of a questionaire sent to 341 hospitals throughout the Republic and South West Africa, asking for details of their caesarean section rate and obstetric anesthetic techniques used. Non-specialist practitioners provided 90% of anaesthetic services in the 131 (38,4%) hospitals from which replies were received. General anaesthesia was used in preference to regional anaesthesia in 90% of these hospitals. Of the institutions surveyed, 24% used neither stomach emptying nor antacid therapy pre-operatively. These and other results pertaining to their choice of anaesthetic agents and techniques are presented and discussed.

The use of chlorazepate for premedication on the night before surgery.

Chlorazepate, a long-acting benzodiazepine, allayed anxiety before operation, being superior to placebo in a double-blind study in which the drug was given the night before surgery. Long-term relief of apprehension before surgery by the administration of chlorazepate, combined with a narcotic analgesic when indicated, is advocated.

Intravenous ketamine anaesthesia for major abdominal surgery--an assessment of a technique and the influence of ataractic drugs on the psychomimetic effects of ketamine.

Eighty-two patients presenting for major abdominal surgery were divided into five groups, and received intravenous ketamine, muscle relaxation and controlled ventilation with oxygen-enriched air. For maintenance of anaesthesia patients were given a single intravenous dose of either droperidol 5 mg, diazepam 5 mg, promethazine 25 mg, flunitrazepam 0.5 mg or lorazepam 2 mg, followed by incremental doses of ketamine. Flunitrazepam and lorazepam were the adjuvants associated with the lowest incidence of dreaming and emergence phenomena; postanaesthetic sequelae occurred most frequently with both ketamine/diazepam and ketamine/droperidol anaesthesia. However, the differences between the five groups failed to reach statistical significance.

The contrasting effects of enflurane on transplacental exchange after methohexitone and ketamine induction of anaesthesia for caesarean section.

Supplementation of general anaesthesia with enflurane 0.6% before delivery of the foetus by elective Caesarean section, produced contrasting effects after methohexitone and ketamine administration. Enflurane, an inhalational agent causing vasodilation and uterine relaxation, enhanced maternal to foetal transplacental exchange following methohexitone induction of narcosis. This beneficial effect of the volatile agent was not seen after ketamine, a vasoconstrictor drug which stimulates myometrial contraction.

The influence of fentanyl on an alfathesin infusion technique.

The effects of fentanyl (1 microgram/kg) supplementing an alfathesin infusion technique were assessed in a double blind study in 53 healthy unpremedicated female patients undergoing therapeutic abortion as outpatients. The addition of fentanyl reduced the tachycardia, tachypnoea and hyperventilation seen in those patients receiving alfathesin alone, without unduly prolonging recovery time. Two patients receiving alfathesin alone developed marked coughing or laryngospasm. Fentanyl would seem to be a desirable addition to an alfathesin infusion technique in unpremedicated patients presenting for outpatient anaesthesia.

A comparative assessment of alfathesin for use in outpatient anaesthesia.

Alfathesin and thiopentone were compared in a double blind study where each drug was given by intravenous infusion supplemented with fentanyl and nitrous oxide, in 54 healthy female patients under-going therapeutic abortion. The two drugs were similar in terms of changes in cardiorespiratory variables, side effects, clinical efficacy, and patient acceptability. Alfathesin produced a significantly more rapid recovery from anaesthesia, without the high incidence of dreams found with thiopentone in this study. Alfathesin would seem to be the preferable drug for use in outpatients undergoing minor surgical operations.

Gastric volume and acidity at caesarean section.

The pulmonary acid aspiration (Mendelson's) syndrome may present after regurgitation and inhalation of acid gastric content during obstetric anesthesia. The stomach contents of 70 mothers were aspirated at caesarean section after pre-operative gastric 'emptying' and alkaline ingestion. The acidity of the gastric aspirate was analysed and volumes were measured. The patients were divided into 5 groups according to the time when gastric aspiration was carried out. A 'safe' gastric pH (pH greater than 3.5) was found in all patients up to 2 hours after antacid ingestion (groups 1-3). However, 2 1/2 hours after antacid ingestion (group 4y, 50% of patients had gastric volumes in excess of 25 ml and a pH of less than 3.5. We therefore recommend that, if general anaesthesia is to be induced or is in progress 2 hours after antacid therapy, the alkaline regimen should be resumed after repeated gastric aspiration.