Task analysis of the preincision surgical period: an independent observer-based study of 1558 cases.

Intense production pressure has focused on the preincision period (from patient-on-table to incision) as an important component of overall operating room efficiency. We conducted a prospective study in which trained independent observers measured the performance of anesthesiologists, surgeons, and nursing staff to determine anesthesia release time (ART, patient-on-table until release for surgical preparation) and surgical preparation time (SPT, start surgical preparation to incision) and the factors, including delays, that affect their duration. We enrolled 1558 patients undergoing elective surgery in a tertiary medical center. The mean ART was 21 +/- 16 min. Mean SPT was 22 +/- 13 min, and mean case length was 207 +/- 123 min. Significant variation was seen in both ART (range, 1-115 min) and SPT (range, 1-130 min). Multivariate regression analysis revealed ASA physical status, age, level of resident training, invasive monitoring, case length, and case number in the room were all positive predictors of ART duration (P < 0.05). In contrast, gender, body mass index, number of anesthesia personnel concurrently in the room, and number of rooms covered per anesthesia attending were not predictors for ART (P > 0.05). Delays affected both ART and SPT and were encountered in 24.5% of all procedures (surgery 66.8%, anesthesiology 21.7%, and logistical 11.5%). For operating room scheduling purposes, we conclude that assigning a constant fixed duration for anesthetic induction is inappropriate and will result in creating erroneous administrative expectations.