Total intravenous anaesthesia with etomidate-fentanyl. Use in general and gynaecological surgery

A preliminary comparison of epidural lidocaine and xylazine during total intravenous anaesthesia in Iranian fat-tailed sheep

The effects of total intravenous anaesthesia using diazepam-ketamine (D-K) mixture in combination with epidural lidocaine or xylazine were studied in 17 healthy, Iranian fat-tailed sheep undergoing hindlimb orthopaedic surgery. All sheep were given diazepam (0.4 mg/kg) and ketamine (4 mg/kg) as induction agents. Following endotracheal intubation and administration of oxygen, the animal received lidocaine (2%, 0.2 ml/kg = 4 mg/kg) or xylazine (0.08 mg/kg, diluted in 0.9% NaCl to a volume of 0.2 ml/kg) epidurally. Anaesthesia was maintained for 174.2 +/- 7.8 minutes by intermittent injection of D-K (2.5 mg/ml and 25 mg/ml, respectively). This drug combination provided satisfactory anaesthesia for more than 2.5 hours. The quality of recovery was good. Our results demonstrate that the combination of total intravenous anaesthesia (D-K) and epidural analgesia (lidocaine or xylazine) provides a suitable technique for hindlimb orthopaedic surgery in sheep. Epidural administration of lidocaine or xylazine provided effective analgesia and significantly decreased the dose of D-K required to maintain anaesthesia. Further studies would be required to determine details of cardiopulmonary effects of D-K infusion.

Analgesia for appendectomy: comparison of fentanyl and alfentanil in children

During etomidate-N2O vecuronium anaesthesia for appendectomy, three groups of 13 children received fentanyl as a 10 micrograms.kg-1 loading dose and 2 micrograms.kg-1 increments in Group F, alfentanil as a 100 micrograms.kg-1 initial loading dose and either 20 micrograms.kg-1 increments in Group AB or 1 microgram.kg-1.min-1 continuous infusion in Group AI. On the basis of intraoperative heart rate changes, the opioid regimen was less efficient in Group AB (P less than 0.05). Based upon equianalgesic cumulative dosage, the alfentanil/fentanyl potency ratio was in the range of 1/10 to 1/13. The awakening time was similar in all groups, as were the duration of postoperative analgesia, the incidence of postoperative pain and the incidence of nausea and vomiting. We conclude that high-dose alfentanil is as efficient as fentanyl for intra and postoperative analgesia in children undergoing appendectomy.

Etomidate by infusion for neuroanaesthesia. Kinetic and dynamic interactions with nitrous oxide

An etomidate infusion was used to anaesthetise twelve patients for spinal surgery; six (group I) with 67% nitrous oxide and six (group II) with oxygen enriched air. Anaesthesia was induced with infused etomidate at a rate of 100 micrograms/kg/minute for 10 minutes and maintained at a rate of 10 micrograms/kg/minute. Recovery was assessed as the time to opening eyes on command (t1) and the time to giving correct date of birth (t2). In group I, mean value for t1 was 37.9 minutes and t2 59.1 minutes which is significantly longer than in group II where mean value for t1 was 9.0 minutes and t2 15.1 minutes. Blood was taken for estimation of etomidate levels. In group I the maintenance level was 501 ng/ml and the plasma clearance 20.9 ml/kg/minute. In group II the maintenance level was 367 ng/ml and plasma clearance 27.3 ml/kg/minute. Etomidate infusion appears to be a suitable alternative for neuroanaesthesia when nitrous oxide is contra-indicated.

Total intravenous anaesthesia

Total intravenous anaesthesia is a feasible alternative to the use of inhalational agents and the rationale behind such a technique is presented. The various intravenous agents are discussed, particularly with regard to their suitability for this form of anaesthesia, and their physiological effects compared with those of the inhalational anaesthetics. Some of the problems associated with the use of total intravenous anaesthesia are mentioned.

Experience with etomidate as part of a total intravenous anaesthetic technique

Etomidate and fentanyl have been used in three different ways as part of a total intravenous anaesthetic technique. The results suggest that etomidate and fentanyl should be infused separately. The quality of induction of anaesthesia following a rapid infusion of etomidate was comparable with that following a bolus injection of thiopentone. None of the techniques had a significantly deleterious effect on the cardiovascular system and, where measured, on respiratory, renal or hepatic function.