Economic analysis and TIVA-TCI
Professor Quirino Piacevoli,
Chief of Department of Intensive Care and Anaesthesia,
ACO San Filippo Neri, Rome, Italy
Evaluation Methods
In 1998, Chalfin wrote that “Some ethical and moral principles render an economic impact irrelevant, for both individual institutions and society as a whole”.
At the same time, it is universally accepted that technology is the chief driver of medical costs. The high cost of medical and nursing personnel together with the use of expensive drugs and disposable items has forced administrators to review the costing process, something to which anaesthesia was previously “immune”. This situation led to “new” approaches such as evidence-based medicine, protocols and guidelines in clinical practice, and the application of cost-benefit criteria in broad terms. In this way the socio-economic impact is evaluated, and not just mere financial saving, hence the possibility of justifying the significant costs incurred in medical practice.
The dynamics under development in this scenario are therefore highly complex, and involve 3 groups:
— the patient’s relatives, who demand treatment without taking the costs involved into consideration at all;
— the doctors, who want to use the most technologically-advanced methods, which they feel are more effective;
— the administrators, who try to limit expenditure without any particular concern for the patient’s wellbeing.
Developing a clinical approach which is increasingly evidence-based provides the appropriate methods to evaluate effectiveness, thus avoiding a situation where clinical decisions are reached empirically or anecdotally. On the other hand, however, economic evaluation, for each level of resource allocation, facilitates the development of an appropriate method in establishing optimal benefits in health care terms. These models should be clearly taken forward together with identical rigour. At this point, it is helpful to clarify a concept that is not generally understood, except by professionals, and indeed not agreed on by all.
The terms “financial aspects” and “economic aspects” are usually considered to be synonymous, however, these differ in terms of evaluation.
Financial evaluation deals with an individual hospital and must therefore consider the general interest. The goal of the hospital is to balance its budget .On the other hand, economic evaluation seeks to improve the “social” budget, including advantages such as the increased “quantity” of health, thus improving the “quality” of life as a consequence.
“Opportunity cost” originates from economic evaluation, and is fundamental in improving a concrete meaning for lack of resources: if a quantity of resources are used for one specific purpose, another possible purpose must inevitably be sacrificed. In this social view, effectiveness is not considered merely as productivity, but as efficiency in achieving a functional allocation of benefits in terms of health, which is inevitably linked to effectiveness. There is thus no contrast between clinical and economic goals. Although it is true that effective technology may be excessively costly, it is equally true that ineffective technology is always a waste, even if it can be provided at low cost. It is clear that the principles of good clinical practice are the necessary premise for an efficient use of resources. Economic resources are limited, and often fall short of what is needed. Guidelines for decision making in allocation of resources are required especially since the alternatives not funded are inevitably penalised as a consequence.
Economic analyses
Evaluation techniques involving the cost-benefit approach must also be able to express the concept of cost-opportunity. Thus, cost analysis (CA), even where it is understood
in the economic and not merely the financial sense, is only a preliminary tool, however useful. “Cost-of-illness” studies have recently been developed within CA itself with the aim of evaluating direct/indirect and tangible/intangible costs. More complex techniques consist of a comparison between alternatives, evaluating both the costs and the results of each. The oldest and best-known of these techniques is “cost benefit analysis” (CBA). Even though the use of this term in the health sector is widespread, in reality the method is almost never applied, because of the intrinsic limit of attempting to monetize both costs and benefits. Indeed, although it offers methods where elements such as suffering, pain and stress associated to a disease, and life itself, can be expressed in monetary terms, such as “willingness to pay” or “human capital”, the intangibility of these dimensions means that evident objections emerge, especially in the clinical field. In order to overcome this obstacle another evaluation method has been developed.This is known as “cost effectiveness analysis” (CEA) and although it is similar in terms of practical application it is completely different. Where CBA is based on the economic principles of so-called “welfare economics”, originally developed at the end of the 19th century, CEA derives from linear programming methods originally applied in the engineering field, but are also applied to economics. Explicitly putting monetary evaluation aside, CEA constructs efficiency indicators, relating a specific measure of effectiveness to the net cost sustained. To measure effectiveness, therefore, the method uses “natural units” such as the number of cases successfully treated, lives saved, or years of life gained.
Otherwise, the simple number of cases treated is only an expression of technical or productive efficiency, and is not immediately translated into results in health-care. Cost utility analysis (CUA) is a different evaluation technique developed within the method of cost effectiveness analysis. CUA uses indicators which attribute value to quality of life through systems chosen by the doctor, the patient, or others. Leaving aside an analysis of the conceptual differences between quality of life and utility, which in cost-utility analysis are frequently considered to be the same, only the indicators used in this method will be examined. The best known of these are the potential years of life lost (or gained), which may be adjusted for quality or for disability; these are known respectively as “quality adjusted life years” (QALYs) and “disability adjusted life years” (DALYs).
However, these aspects should be examined within the general definition of the conditions required when undertaking a “cost-effectiveness” study in anaesthesia, and may be summed up in the following 8 points:
1) explicit description of the problems that are the subject of research, and of the possible alternatives;
2) explicit description of the prospective study;
3) definition of all costs;
4) definition of all benefits;
5) application of actualisation techniques;
6) determination of “cost- effectiveness” percentages;
7) application of sensitivity analysis;
8) recognition of limiting factors.
These are some of the 10 principles reported by the American Government Office of Technology Assessment (OTA) which specify the need not only to identify the goals in the description of the problems subject of the research and of the prospective study, but also to distinguish between private costs and benefits and social costs and benefits.
Discussion
First of all it should be noted that there is a general consensus in the literature resulting from studies undertaken in various countries regarding hospital cost analysis particularly concerning drugs used in anaesthesia. It is repeatedly reported that the percentage cost for these drugs ranges from 0.25% to 0.45% of the overall total costs. Furthermore, if costs for anaesthesia are compared to overall costs of the surgical intervention itself, the percentage is about 1%! In other words when compared with overall hospital costs, anaesthesia costs become a niche expense.
However, if we specifically examine some of the major publications in the literature on cost effectiveness analysis in totally intravenous anaesthesia we can confirm that whilst the studies are extremely rigorous from the clinical point of view, they are far less so from the economical point of view. One of the most common occurrences is that different studies attribute different items involved in both indirect and direct costs and by doing so render any form of comparison negligible. Furthermore most studies fail to clearly indicate the aim in terms of cost analysis and benefits. Some examples of this can be found in the following publications: Boldt et al (1996) conclude the study by stating that costs for isoflurane low-flow system were lower than propofol however there is no explanation of the evaluation methodology for vapour consumption. The Authors also state that propofol patients remained in the post anaesthesia care unit (PACU) for a shorter period of time and even though this is reported differently elsewhere in the literature, this result was not cost evaluated.
A further study by Fombeur et al (2002) concludes stating that anaesthesia with TCI propofol was more expensive than with desflurane ($45 versus $28 per patient). Effectiveness was defined as the absence of postoperative nausea and vomiting (PONV) and was found to be similar for both drugs 24 hours post operatively. This result also contrasts with others in the literature. Another study by Suttner et al (1999) concludes that TCI anaesthesia using proprofol/remifentanil was associated with the highest intra operative costs but with the fewest side effects such as postoperative nausea and vomiting and earlier discharge from PACU. Another publication by Luntz et al (2000) states that propofol and sevoflurane based anaesthesia maintenance was less costly if propofol was used only for induction and sevoflurane for maintenance. Zollinger (2005) states in a presentation that outcome assessment following general anaesthesia remains a complex issue from both the clinical and as a consequence from the economic point of view.
Elliott et al (2002) in a randomised study from the United Kingdom found that the total cost for drugs used in day surgery the propofol/isoflurane combination was the cheapest whilst TIVA with propofol was the highest than all other groups. None of these strategies affected length of stay. Yuill and Gwinnutt (2002) also in a prospective randomised trial compared compared the cost effectiveness of anaesthetic regimens. It was found that sevoflurane/ sevoflurane is not a cost effective regimen for day surgery in adults or children. It was associated with higher rates of PONV than propofol followed by propofol, isofurane or sevoflurane. It was more expensive than mixed anaesthesia regimens and there were no statistically significant differences in the incident of PONV between the regimens that used propofol for induction. However, there were statistically significant differences in the variable cost of the regimens. The propofol/isoflurane regimen was associated with the lowest cost per episode of PONV avoided.
An important review from Canada by Alhashemi et al (1997) on cost-effectiveness of inhalational, balanced and TIVA for ambulatory knee surgery reports that 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. The BAL option results in the most rapid time to awakening, but has a higher incidence of PONV . Overall, INH had the lowest anaesthetic costs, and similar nursing and extra in-hospital costs.
In conclusion considering that many studies take PONV into consideration to evaluate effectiveness it should be stated that the most reliable study is the review by Yuill and Gwinnutt (2002) where 1893 adults were examined for cost analysis from October 1999 to January 2001 who underwent day surgery procedures. After randomisation 95 adults were withdrawn and the remaining 1063 patients were divided as follows: 265 propofol/propofol, 267 propofol/isoflurane, 280 propofol/sevoflurane, 251 sevoflurane/sevoflurane .The occurrence of PONV, at varying degrees of severity, within the randomisation categories for all PONV and for one or more episodes of vomiting, a substantially larger proportion of cases occurred with the sevoflurane/sevoflurane regimen than in the others (30%) versus propofol/propofol that appeared to have the lowest incident. No statistically significant differences were found between the randomisation arms in the incidence for overnight admission. Preference for induction of anaesthesia show that 79% of patients who had received intravenous induction would prefer that method in the future to inhalational induction, versus 64% who had received inhalation induction .
Sevoflurane/sevofurane was less effective and more costly that either of the mixed anaesthesia regimens ( i.e was dominated by them). It was less effective, but less costly than the propofol/propofol regimen. No statistically significant differences were found in the rate of PONV between propofol/propofol, proofol/sevoflurane and propofol/isoflurane regimens. If this is because the regimens were equivalent, then the least costly of these alternatives is likely to be the most cost-effective. In this analysis that would be propofol induction followed by isoflurane maintenance anaesthesia.
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