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.

Resident teaching versus the operating room schedule: an independent observer-based study of 1558 cases.

Efforts to improve operating room efficiency may threaten clinician training. Therefore, we designed a prospective, observational study to determine the actual time spent teaching anesthesiology residents during the interval from patient-on-table to skin incision and to determine whether anesthesia teaching in the peri-induction period increases the time to surgical incision. This study was conducted in an inpatient operating room suite of a tertiary academic medical center. Of 1558 cases examined, 75% had an element of teaching (mean percent teaching per case = 46.4). A 33% decrease in teaching occurs when the attending anesthesiologist concurrently directed care in 2 rooms (P < 0.001). The percent teaching significantly increased as a function of ASA physical status classification and time of day of surgical case (P = 0.001). Teaching accounted for a mean increase of time to incision of 4.5 +/- 3.2 min, but represented only 3% of the mean surgical case length (207 +/- 132 min). We conclude that teaching occurs in the majority of cases in the operating room and although it contributes to increased time to incision, this increase is insignificant compared with the time required to complete the surgical procedure.

Can the attending anesthesiologist accurately predict the duration of anesthesia induction?

In a prospective, observational study, the attending anesthesiologists' prediction of anesthesia release time (ART) of the patient to the surgical team was highly correlated with actual ART (r = 0.77; P < or = 0.001). However, this was true only in the aggregate (n = 1265 patients). Indeed, offsetting degrees of under- and over-predicting (24% each) reduced accuracy to only 53% per individual case. For example, under-prediction was associated with ASA physical status IV, a regional anesthetic technique, age >65 yr, and the use of invasive hemodynamic monitoring (P = 0.006). In fact, as the degree of case difficulty increased, the correlation coefficient between predicted and actual ART decreased, indicating a poor predictive value with more difficult inductions (r = 0.82 to r = 0.44; P < or = 0.004). We conclude that knowledge of the presence of specific factors that lead to inaccurate predictions of time required for induction of anesthesia may enhance the accuracy of the operating room schedule.