PROPOFOL - A PHARMACOECONOMIC APPRAISAL OF ITS USE IN DAY-CASE SURGERY

Propofol is an intravenous anaesthetic agent that has become widely us ed in day case surgery. It induces anaesthesia rapidly and 'smoothly', is associated with a quick recovery and has a lower incidence of post operative nausea and vomiting (PONV) than other agents. In studies com paring propofol with other intravenous anaesthetics (most commonly thi opental sodium) in day case surgery, the use of propofol as induction and/or maintenance anaesthesia was associated with a shorter time to i ntermediate recovery (street fitness or time to discharge), although t he mean time difference was generally less than 1 hour. However, when compared with volatile anaesthetics (particularly desflurane), the dif ferences in time to discharge were smaller. Propofol is also associate d with less PONV than barbiturates, volatile anaesthetics or barbitura te/volatile anaesthetic combinations in the immediate postoperative pe riod. The faster recovery time and the decreased incidence of PONV hav e potential pharmacoeconomic implications. Delayed recovery can increa se the use of hospital resources and decrease patient throughput and P ONV can incur costs due to an increase in adjunctive medications usage (e.g. antiemetics), nursing time or unintended admissions. The pharma coeconomic significance of these properties of propofol requires forma l evaluation. Pharmacoeconomic investigations, such as cost-effectiven ess, cost-benefit and cost-minimisation studies, which include clinica l outcome parameters are difficult to conduct in anaesthesia since the re are no objective measures of equipotency between anaesthetic agents and because there is no specific health outcome associated with the d elivery of anaesthesia. At present, cost-utility studies are not possi ble because there are no validated instruments for measuring utility i n the provision of anaesthesia. To date, pharmacoeconomic analyses of propofol (and other anaesthetic agents) in day case surgery have been restricted to partial cost analyses. Only 2 of these have included the cost of drug wastage, an important consideration since propofol conta ins no preservative. With 1 exception, these studies have only include d drug acquisition costs and propofol was reported to be approximately 1- to 3-fold as costly as other intravenous/inhalational agents. Howe ver, these limited analyses have little applicability since they do no t include all relevant costs. In addition to drug acquisition costs, p har macoeconomic studies should also include other direct costs such a s the cost of adjunctive medications (including treatment necessary fo r adverse events), equipment and staff time, indirect costs such as lo ss of productivity and/or wages and intangible costs such as patient s atisfaction and quality of life. A few studies have attempted to quant ify some of these factors. Based on differences in recovery time, 2 st udies have estimated a decreased demand for nursing staff time associa ted with the use of propofol compared with thiopental sodium/isofluran e. In addition, informal patient satisfaction assessments show propofo l to be equal to or better than other anaesthetic agents. With these b roader considerations, it thus remains for future studies to quantify the intangible and indirect costs associated with propofol anaesthesia , to determine whether differences in recovery between propofol and ot her agents (especially the newer inhalational anaesthetics) are of eco nomic importance, and to identify those instances where propofol use p rovides the greatest value for available funds.