Sequencing cases in the operating room: predicting whether one surgical case will last longer than another.

UNLABELLED: A microscope will be used for the first case of the day in operating room (OR) 1 and then may be used in the second case of the day by a different surgeon in a different OR, OR 2. Provided that the probability is reasonably high that the first case of the day in OR 2 will last longer than the first case in OR 1, the OR manager can be confident in scheduling the microscope to be used by both surgeons on the same day. The OR manager can use statistical decision theory to sequence cases to decrease the impact of limitations in equipment or personnel on case scheduling. This increases utilization of both the capital equipment and OR time. In this study, we derived equations that can be programmed into a surgical services information system to reliably estimate the probability that one case will have a longer duration than another. We confirmed the accuracy of our method by using actual case duration data. IMPLICATIONS: Our statistical method uses historical case duration data from an operating room information system to estimate the actual probability to within 1.5% that the second case of a pair will last longer than the first case of a pair.