PURPOSE The economics of the use of an anesthetic drug or device that produces benefit through reduction in operating room (OR) time depends on the day of the week and the total hours of surgical cases in the OR in which they are performed. Principally, this has to do with different durations of the regularly scheduled workday in the ORs within and among hospitals. We tested hypotheses relevant to the economic benefit of avoiding prolonged tracheal extubation times. METHODS Observational data were obtained from a multiple-specialty academic tertiary hospital that uses an anesthesia information management system. Prolonged tracheal extubation times were considered those with tracheal extubations occurring 15 min or more after the end of surgery. The assessment of prolonged tracheal extubation times was limited to cases for which the patient's trachea was intubated and extubated while physically in the OR. Percentages were calculated for each of n = 39 four-week periods. Results are reported as mean (standard error of the mean) of these percentages, and the phrases "at most/least" are used to refer to the corresponding 95% confidence limits. RESULTS At most, 6.1% [mean 5.5 (0.3)%] of the prolonged tracheal extubation times were attributable to cases that did not end during regular workdays from 7:00 AM-10:59 PM. At least 55.6% of prolonged tracheal extubation times occurred during cases on regular workdays and in an OR with more than eight hours of cases and turnovers [mean 57.0 (0.9)%; P < 0.0001]. This percentage was 23.8 (0.8)% larger than for all other cases. CONCLUSIONS In the absence of an accurate facility-specific cost analysis, prolonged tracheal extubation times should not be treated as fixed costs but as resulting in proportionally increased OR variable costs.