Impact on Operating Room Efficiency of Reducing Turnover Times and Anesthesia-Controlled Times

To the Editor:

Friedman et al¹ report on the benefit of reducing turnover time (TT) and anesthesia-controlled times (ACT) on the efficiency of use of operating room (OR) time, for a single surgeon performing inguinal hernia repairs. We believe this to be a superb study taking advantage of an excellent opportunity to describe results that can be repeated elsewhere by others. The use of parallel processing has great potential to increase both the efficiency of use of OR time and contribution margin per OR hour. However, being a management case study with a single combination of surgeon and surgical suite, the n = 1. Understanding how to extrapolate results to other settings requires precise understanding of the reasons why an increase in OR efficiency was achieved. The authors¹ suggest that their findings differ from those of Dexter et al² because the latter study was “... working based on the standard linear structure of patient flow through the operating day.” As our paper² did not make that assumption, the differences reflect other factors.

First, Dexter et al² considered a single OR with fixed hours,³ in which a case would be cancelled if it could not start sufficiently early to be expected to be completed on time.⁴ In contrast, Friedman et al performed the cases scheduled each day. The implication is that, to gain benefit from reductions in TT and ACT, there should not be the requirement that the time reductions be achieved every time to perform a case.⁴

Second, by studying brief cases of the same procedure(s) performed by a single surgeon, Friedman et al¹ had small standard deviations of surgical times. The observed mean reduction in TT and ACT times was 15.8 minutes, larger than the 9.5 minutes standard deviation of surgical times. Consequently, small numbers of cases needed to be performed each day for there to be a detectable benefit, as shown by Dexter et al.^2,5 The benefits of reducing TT and ACT are large when these times are long relative to the standard deviation of surgeon-controlled times.² The implication is that efforts should focus attention on procedures with predictable surgical times.

Third, whereas Dexter et al considered individual days,² Friedman et al¹ considered a surgeon's workload over more than 1 day. Suppose that the choice of the day on which each case was performed had not been changed by the studied surgeon as a result of the reduction in TT and ACT. Then, Friedman et al would have shown a reduction in TT and ACT, as before, but instead of an increase in OR efficiency, there would have been simply an increase in under-utilized OR time.^4–6 Only by the surgeon's choice of changing the days on which cases were scheduled were the reductions in TT and ASC effective at increasing the efficiency of use of OR time.⁵ Had the Thursday afternoon allocated time described in Friedman et al¹ not been given way, OR efficiency would have been unchanged.^4–6 Very large increases in OR efficiency can be achieved by reducing TT and ACT provided staffing and case scheduling are changed simultaneously.^4–6

Franklin Dexter, MD, PhD
Departments of Anesthesia and Health Management & Policy
Division of Management Consulting
University of Iowa
Iowa City, IA
Franklin-Dexter@UIowa.edu