Mathematical modeling to define optimum operating room staffing needs for trauma centers

BACKGROUND: Level II trauma centers may be verified (1999, American College of Surgeons Committee on Trauma) with an on-call operating room team if the performanc e-improvement program shows no adverse outcomes. Using queuing and simulati on methodology, this study attempted to add a volume guideline. STUDY DESIGN: Data from 72 previously verified trauma centers identified multiple demogra phic factors, including specific information about the first trauma-related operation that was done between 11:00 PM and 7:00 AM each month for 12 con secutive months. RESULTS: The annual admissions averaged 1,477 for 37 Level I trauma centers, 802 for 28 Level II trauma centers, 481 for 4 Level III trauma centers, and 731 fo r 3 pediatric trauma centers. The annual admissions correlated with the num ber of operations done between 1 1:00 PM and 7:00 AM (p < 0.001). These 946 operations were performed by general surgery (39%), neurosurgery (8%), ort hopaedic surgery (33%), another specialty (9%), or multiple services (10%). Admission to operation time was within 30 minutes for 12.1% of patients (2 .6% for blunt and 24.1% for penetrating injuries). The probability of opera tion within 30 minutes of arrival varied with the number of admissions and with the percentage of penetrating versus blunt injuries. The likely number of operations from 11:00 PM to 7:00 AM would be 19 for 500 annual admissio ns, 26 for 750 annual admissions, and 34 for 1,000 annual admissions, with 5.83, 7.98, and 10.13 patients, respectively, going to operation within 30 min. The probability that two rooms would be occupied simultaneously was 0. 14 and 0.24 for centers admitting 500 and 1,000 patients, respectively. CONCLUSIONS: Trauma centers performing fewer than six operations between 11:00 DM and 7: 00 AM per year could conserve resources by using an immediately available o n-call team, with responses monitored by the performance-improvement progra m. (J Am Coll Surg 2001;192:559-565. (C) 2001 by the American College of Su rgeons).