In Reply:--Cost-effectiveness studies compare the costs of different therapies to achieve the same outcome. In the part of our study that used charges, we did not do a cost-effectiveness analysis. Instead, we addressed whether strategies to decrease postanesthesia care unit (PACU) supply costs would decrease PACU costs substantively. They would not. Hagan points out that "one of the benefits of cost-effecttiveness studies is the ability to provide to policy-makers alternatives in resource allocation." Although I agree, I think that other types of cost analyses can be beneficial. This minor part of our study was a valuable prelude to most of our analysis.
To assess the significance of supplies on PACU costs, we used relative charges as proxies for relative costs. We did not make this assumption capriciously but did so based on studies that have evaluated the validity of the relationship. [1,2]Nevertheless, the important question is not whether relative charges are statistically different from relative costs. They will be under many circumstances. The important question is whether the degree of inaccuracy is sufficient to affect our conclusions. Charges for supplies accounted for 2% (95% confidence interval 0-3%) of the PACU bill. Therefore, I think that a change in the analysis is unlikely to show that supplies were a major part of the bill. We could have increased our sample size. However, I am skeptical that we then would have found supplies to be important cost items in the PACU.
Finally, Hagan states that "the number of personnel required does not depend on the peak number of patients in the [PACU]." If this statement were true, our results would be of little value. However, the claim is incorrect. The American Society of Post-Anesthesia Nurses (ASPAN) recommends that each PACU nurse care for two or fewer patients simultaneously. Following their standard, the peak number of nurses required equals half the peak number of patients.
Hagan's point about the number of personnel leads to the question of whether PACU personnel costs are proportional to the peak number of patients in the PACU. This relationship between cost and peak number of patients will hold for almost all PACUs. However, there are exceptions. The relationship assumes that there are dedicated PACU nurses. For example, some ambulatory surgical centers do not have dedicated PACU personnel. By having these nurses perform other (non-PACU) duties when they are not needed in the PACU, perioperative costs can be decreased. I do not know of a study that has assessed whether this cost-saving approach affects the quality of patient care.
Franklin Dexter, M.D., Ph.D.; Department of Anesthesia; The University of Iowa; Iowa City, Iowa 52242-1079.
(Accepted for publication March 9, 1995.)
