Cost-effectiveness of inhalational, balanced and total intravenous anaesthesia for ambulatory knee surgery

A randomized, blinded clinical trial was undertaken to compare recovery characteristics and cost-benefits associated with three general anaesthetic techniques for arthroscopic knee surgery in an ambulatory care setting.

Ninety three, ASA Physical Status I-II patients were randomly allocated to receive one of three types of general anaesthesia: isoflurane/fentanyl/N2O (Group INH); alfentanil/N2O (Group BAL); or propofol/alfentanil/O2 (Group TIVA). Postoperative recovery profiles were evaluated at 30, 60, 90 and 120 min after emergence from anaesthesia, and direct and indirect costs of each anaesthetic were compared.

The most rapid emergence was observed in Group BAL (2.2 +/- 1.5 min, P < 0.0001 compared with groups INH and TIVA), although the incidence of post-operative nausea and vomiting was also highest in this group (P = 0.02 compared with groups INH and TIVA). However, overall patient satisfaction, and mean times to discharge from the Post Anesthesia Recovery Unit and hospital, were rapid and similar in all three groups. During anaesthesia which lasted 40-45 min, nearly a four-fold difference was observed in the direct costs of anaesthetic drugs: $16.4 +/- 4.4 (Group INH), $45.3 +/- 11.4 (Group BAL) and $63.4 +/- 17.9 (Group TIVA, P < 0.001 between groups); while indirect costs were similar.

For arthroscopic knee surgery, INH anaesthesia with isoflurane/fentanyl/N2O is associated with similar hospital discharge times, and comparable levels of patient satisfaction as either BAL or TIVA. While indirect costs were similar, lower direct costs suggest that there may be a pharmacoeconomic benefit associated with the use of a "standard" isoflurane/fentanyl/N2O anaesthetic in certain day care surgery procedures.