Low-flow anaesthesia. Practice, cost implications and acceptability.

An 8-week survey was conducted to determine whether the introduction of low-flow anaesthesia (a fresh gas flow of 4 litres/minute or less) into routine use would be acceptable to members of a representative anaesthetic department and if the consequent reduction in use of volatile anaesthetics would result in financial savings. The hourly consumption of the volatile agents was measured during anaesthesia conducted using either conventional or low fresh gas flows. Anaesthetists' acceptance of low-flow anaesthesia was assessed using a questionnaire. Data were gathered on 286 patients undergoing inhalational anaesthesia for routine operative procedures. A 54.7% reduction in the consumption of isoflurane and a 55.9% reduction in that of enflurane was found. Of the 28 anaesthetists at the hospital, 21 would use low-flow anaesthesia routinely. The routine use of low-flow anaesthesia would therefore be acceptable and could result in annual savings of 26,870 pounds at Northwick Park Hospital.

[Intravenous anesthesia with propofol versus thiopental-/enflurane anesthesia. A consumption and cost analysis]. / Intravenöse Anästhesie mit Propofol versus Thiopental-/Enflurananästhesie. Eine Verbrauchs- und Kostenanalyse.

It may be possible to reduce costs in anaesthesia when there is a choice of drugs and methods. Two of the most widespread techniques are inhalation anaesthesia with enflurane following induction with thiopentone, and intravenous anaesthesia (IVA) with propofol. The aims of our study were to compare the costs, effectiveness and side effects of the anaesthetics involved in these two techniques, and to measure significant clinical parameters. METHODS. After approval by the hospital ethics committee, 40 adult patients of ASA physical status 1 and 2 who had been scheduled for elective septorhinoplasty and had given informed consent were entered in our prospective, single-blind randomized study. In 20 patients anaesthesia was induced with thiopentone (4-5 mg/kg) and suxamethonium (1-1.5 mg/kg) and maintained with enflurane. The other 20 patients received an initial i.v. bolus of propofol (2-2.5 mg/kg) followed by a propofol infusion adjusted to their individual clinical needs. Ventilation was performed in both groups with 70% nitrous oxide in oxygen, using a nonrebreathing system. Muscle relaxation was maintained with atracurium. The amounts of anaesthetics, oxygen, nitrous oxide, and muscle relaxants used were measured and a record of the costs was kept. In addition, circulatory and respiratory parameters and quantitative and qualitative aspects of recovery from anaesthesia were recorded. RESULTS. The biometric and clinical data did not differ significantly between the two groups. For induction, 382 (+/- 55.9) mg thiopentone costing 1.24 Swiss francs (SFr), or 172 (+/- 25.1) mg propofol costing 11.87 (SFr) was used. For maintenance, 28.3 (+/- 6.4) ml enflurane costing 21.96 SFr/h, or 450.7 (+/- 247) mg propofol costing 29.75 SFr/h was required. The need for muscle relaxants, oxygen, and nitrous oxide was also not significantly different in the two groups. Additional expenses were due to relaxation antagonists (1.91 SFr per patient in both groups) and to the perfusion pump system (8.60 SFr per patient in the IVA group only). Circulatory and respiratory parameters remained normal in both groups. In the propofol group, the heart rate tended to increase more at the beginning of anaesthesia, whereas later on it showed a tendency to lower values than in the thiopentone/enflurane group. Patients receiving IVA generally had a shorter awakening period, a higher degree of wellbeing during recovery, and needed less systemic analgesics (P < 0.05). CONCLUSIONS. Costs of anaesthetic drugs in the IV group totalled 54.50 SFr during the first hour, i.e. 1.65 times the costs in the thiopentone/enflurane group for the same time. However, with continuing duration of anaesthesia this ratio declines to 1.43 in anaesthesia lasting 2 h. In addition, IVA patients had a noticeably faster and far more pleasant recovery. Minute ventilation, oxygen consumption, heart rate and CO2 production indicated a less pronounced stress response and sympathetic activity during and after propofol. Quicker recovery of cognitive and psychomotor abilities, less postoperative pain and less impairment of respiratory function after IVA may lead to an earlier release from the postoperative recovery unit. This might be a cost-reducing factor that should be taken into account when these two anaesthetic regimens are concerned.