Practical pharmacoeconomics with TIVA

Dr Lawrence Rowe,

Consultant Anaesthetist, Norfolk and Norwich University Hospital,

Colney Lane, Norwich, NR4 7UY

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Introduction

Anaesthetists are often targeted by managers seeking to make quick savings because their drugs are easily accounted for and it is more politically acceptable to make savings here rather than by addressing staffing costs[1]. Anaesthetists know however that the choice of anaesthetic drugs is an important factor in patient outcome and satisfaction after surgery. Managers and anaesthetists who seek to minimise costs across the board without regard to patient outcome are not doing their patients or their institutions any favours. It is much more important to apply appropriate economic analyses such as cost benefit and cost effectiveness analyses[2,3]. For example it may be necessary to spend a small amount more on a type of anaesthetic to obtain a much larger economic benefit later on.

Economic analyses applied to anaesthesia (Cost minimisation, cost benefit and cost effectiveness)

Cost minimisation should not be used in the context of comparing intravenous and volatile anaesthesia. Cost minimisation is a simple comparison of direct costs and makes the assumption that there are no significant differences in outcomes between the two drugs. There are many studies which show that for the comparison of intravenous and volatile anaesthetics this is not the case.

Cost benefit and cost effectiveness analyses take into account differences in outcomes and are more appropriate tests to use when comparing anaesthetic drugs. The costs of anaesthetic drugs are small compared to the cost of keeping patients in hospital longer. Intravenous anaesthesia, even with the most expensive form of propofol is more cost beneficial than volatile anaesthesia. Factors which need to be considered are wake up time in theatre, turn around time between cases, time spent in recovery, need for intervention by staff and anti emetic drugs in the post anaesthetic care unit or recovery wards.

Putting the costs into perspective

Doctors and managers often lose sight of the fact that anaesthetic drug costs only account for a small fraction of the total cost of the surgical procedure when surgical disposables, staff costs and fixed overhead costs are taken into account. The drug costs for a typical day case procedure are around 4% of the total cost of the procedure[4] and are less than 1% for a major inpatient procedure.

Generic versions of propofol and newer pumps

Recently, newer pumps using ‘open’ Target Controlled systems have become available. This means that cheaper generic forms of propofol can be used by Target Controlled infusion (TCI). TCI using generic propofol is now one of the cheapest forms of anaesthesia for most procedures (fig1). Even taking into account the cost of providing new pumps this is a worthwhile exercise because the new pumps will pay for themselves within a few months. Departments which have switched totally to generic propofol have demonstrated significant savings in short periods of time.

Figure 1.

Use of Remifentanil

Remifentanil infusion has become a popular adjunct to anaesthesia over the last few years. It has a significant hypnotic sparing effect which reduces the amount of hypnotic required particularly when a depth of anaesthesia monitor is used. This reduction in anaesthetic requirement can be used to offset the cost of using Remifentanil. Some cases which previously would have required post operative ventilatory support in an intensive care unit can now be managed safely in a high dependency unit or ordinary ward which can dramatically reduce the overall cost of the procedure.

Summary

Anaesthetic costs are small so the choice of anaesthetic should be made with regard to likely postoperative outcome rather than to the cost in theatre. Patients rate the absence of nausea higher than other postoperative outcomes[5]. Delays in the operating department are far more significant than the cost of drugs [6]. The introduction of open TCI systems using generic propofol preparations makes TIVA even more cost effective and cost beneficial than it was before.

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2. Watcha, M. F. and White, P. F. Economics of anesthetic practice. Anesthesiology 1997; 86: 1170-1196
3. Rowe W L, Economics and Anaesthesia, Anaesthesia 1998; 53(8):782-788
4. Rowe, W. L. and Kasnowski, Z. Anaesthetic costs in day surgery. The Journal of One-Day Surgery 1995; 4: 7-8
5. Broadway, P. J. and Jones, J. G. A method of costing anaesthetic practice. Anaesthesia 1995; 50: 56-63
6. Orkin FK. What do patients want? Preferences for immediate recovery. Anesthesia & Analgesia 1992; 74(S): 225