Half (53.0% ± 0.6%) of the ASA AQI–reported weekly anesthesia workload was completed by 1:00 PM, local time, on regular workdays. The busiest 8-hour interval was from 7:30 AM to 3:30 PM, and it accounted for 70.3% ± 0.7% of anesthetic minutes (Table 1 and Fig. 2). That 7:30 AM to 3:30 PM interval (using local times) accounted for 74.2% ± 0.7% of the workload on regular workdays. The corresponding interval relevant to staffing of national call centers (6:30 AM to 6:30 PM Central Time) accounted for 82.2% ± 0.7% of anesthetic minutes (Fig. 3). Less than 10% of anesthetic minutes occurred on weekends (P < 0.0001, 5.2% ± 0.1%).
Although most facilities completed the majority of their weekly anesthesia workload in the mornings of regular workdays (P < 0.0001, 62.3%, 58.6%–66.1%), just 24.4% of the University and large community hospitals did so (P = 0.0008 relative to half; 13.8%–38.4%).
Slightly more than half of the U.S. national OR workload is completed slightly after noon of regular workdays. Anesthesia providers providing direct OR clinical care 5 days per week from 7:30 AM to 3:30 PM would result in an average time of 11:30 AM (i.e., by noon). Thus, the results likely indicate longer workdays than previous analyses of 2004 and 2006 Medical Group Management Association data.6,d
Even though many hospitals have nearly every anesthetizing location in use >8 hours daily, most facilities nationwide complete most of their weekly anesthesia minutes by noon of regular workdays. Thus, the results match the tendency of U.S. facilities to open additional OR(s) when the sum of the hours of cases and turnovers per OR per workday is nearly 8 hours.18–20 Opportunity for greater use of the capital (building and equipment) probably would involve the use of additional anesthesia providers representing a second shift or use of weekends. However, scheduling cases <8 hours has the benefit of reducing patient and surgeon waiting on the day of surgery,21–24 although such limitation in scheduled hours of surgery does not reduce complication rates or mortality.19,25 Rather than the traditional full day in a large hospital caring for surgical inpatients having major procedures, shorter hours may provide what many patients want21: morning surgical start times to facilitate outpatient and short-stay procedures1,22–24,26 that provide the most predictable experience for patients and surgeons.
Our results were limited to the study of cases and minutes of OR anesthesia, as needed for our companion paper exploring the timing of activity at a national call center.7 Planning remote expert “knowledge consultation”27 for guiding medical decisions depends on the timing of calls during the week, as provided by Figure 3. Such consultation can be, for example, to support telemedicine services to anesthesia providers facing unfamiliar clinical scenarios such as managing rare diseases.7 The cases and minutes of OR anesthesia do not reveal other activities, clinical (e.g., obstetrics, critical care, and acute and chronic pain medicine), non-clinical (management, education, and research),28 and availability for clinical work.8 For example, although 5.2% ± 0.1% of minutes of care were performed on weekends, anesthesia providers needed to be scheduled to be available during these 28.6% minutes of calendar time (i.e., 2 of 7 days).
a http://FDshort.com/CostBuildSmallASC. Accessed November 27, 2014.
b Feryal Erhun, Wednesday, November 12, 2014, WC40 INFORMS 2014 Meeting in San Francisco, CA. Available at: http://FDshort.com/INFORMSascTripleR. Accessed November 27, 2014.
c The times in the AQI database were stored in the local time zone. They were converted to Central Time based on the zip code of the location of the case and the date of the start of the case. We used Central Time, as a matter of convenience, because the geographic center of population of the U.S. is Central Time. The American Society of Anesthesiologists and AQI are in Chicago, Illinois, which follows Central Time. The Central Time zone is Coordinated Universal Time (UTC) minus 6 hours during Standard Time and minus 5 hours during Daylight Savings Time. Available at: http://en.wikipedia.org/wiki/Mean_center_of_the_United_States_population, www.timetemperature.com/tzmo/plato.shtml, and www.timetemperature.com/tzil/chicago.shtml. Accessed April 1, 2014.
d Abouleish A, Evenson TB. The fallacy of the field of dreams business plan: a downward trend in anesthesiology productivity. ASA Newslett 2007;71:30–2.
1. Bayman EO, Dexter F, Laur JJ, Wachtel RE. National incidence of use of monitored anesthesia care. Anesth Analg. 2011;113:185–9
2. Abouleish AE, Prough DS, Whitten CW, Zornow MH, Lockhart A, Conlay LA, Abate JJ. Comparing clinical productivity of anesthesiology groups. Anesthesiology. 2002;97:608–15
3. Dexter F, Weih LS, Gustafson RK, Stegura LF, Oldenkamp MJ, Wachtel RE. Observational study of operating room times for knee and hip replacement surgery at nine U.S. community hospitals. Health Care Manag Sci. 2006;9:325–39
4. Berry M, Berry-Stölzle T, Schleppers A. Operating room management and operating room productivity: the case of Germany. Health Care Manag Sci. 2008;11:228–39
5. Marcon E, Dexter F. An observational study of surgeons’ sequencing of cases and its impact on postanesthesia care unit and holding area staffing requirements at hospitals. Anesth Analg. 2007;105:119–26
6. Schubert A, Eckhout GV, Ngo AL, Tremper KK, Peterson MD. Status of the anesthesia workforce in 2011: evolution during the last decade and future outlook. Anesth Analg. 2012;115:407–27
7. Dexter F, Rosenberg H, Epstein RH, Semo JJ, Litman RS. Implications of national anesthesia workload on the staffing of a call center: the malignant hyperthermia consultant hotline. A&A Case Reports. 2015;5:43–6
8. Dexter F, Epstein RH. Holiday and weekend operating room on-call staffing requirements. Anesth Analg. 2006;103:1494–8
9. Law AM, Kelton WD Simulation Modeling and Analysis. 19912nd ed. New York McGraw-Hill Inc.:551–3
10. Dexter F, Macario A, Qian F, Traub RD. Forecasting surgical groups’ total hours of elective cases for allocation of block time: application of time series analysis to operating room management. Anesthesiology. 1999;91:1501–8
11. Dexter F, Marcon E, Epstein RH, Ledolter J. Validation of statistical methods to compare cancellation rates on the day of surgery. Anesth Analg. 2005;101:465–73
12. Dexter F, Epstein RH, Marcon E, Ledolter J. Estimating the incidence of prolonged turnover times and delays by time of day. Anesthesiology. 2005;102:1242–8
13. Dexter F, Marcon E, Aker J, Epstein RH. Numbers of simultaneous turnovers calculated from anesthesia or operating room information management system data. Anesth Analg. 2009;109:900–5
14. Ledolter J, Dexter F, Epstein RH. Analysis of variance of communication latencies in anesthesia: comparing means of multiple log-normal distributions. Anesth Analg. 2011;113:888–96
15. Dexter F. High-quality operating room management research. J Clin Anesth. 2014;26:341–2
16. Austin TM, Lam HV, Shin NS, Daily BJ, Dunn PF, Sandberg WS. Elective change of surgeon during the OR day has an operationally negligible impact on turnover time. J Clin Anesth. 2014;26:343–9
17. Epstein RH, Dexter F, Brull SJ. Cohort study of cases with prolonged tracheal extubation times to examine the relationship with duration of workday. Can J Anaesth. 2013;60:1070–6
18. Masursky D, Dexter F, O’Leary CE, Applegeet C, Nussmeier NA. Long-term forecasting of anesthesia workload in operating rooms from changes in a hospital’s local population can be inaccurate. Anesth Analg. 2008;106:1223–31
19. Dexter F, Marco AP. Rationale for anesthesia groups to run additional flexible operating rooms for multiple surgeons who have scheduled more than 8 hours of cases. Anesth Analg. 2011;113:1295–7
20. Sulecki L, Dexter F, Zura A, Saager L, Epstein RH. Lack of value of scheduling processes to move cases from a heavily used main campus to other facilities within a health care system. Anesth Analg. 2012;115:395–401
21. Dexter F, Birchansky L, Bernstein JM, Wachtel RE. Case scheduling preferences of one Surgeon’s cataract surgery patients. Anesth Analg. 2009;108:579–82
22. Smallman B, Dexter F. Optimizing the arrival, waiting, and NPO times of children on the day of pediatric endoscopy procedures. Anesth Analg. 2010;110:879–87
23. Wachtel RE, Dexter F. Influence of the operating room schedule on tardiness from scheduled start times. Anesth Analg. 2009;108:1889–901
24. Wachtel RE, Dexter F. Reducing tardiness from scheduled start times by making adjustments to the operating room schedule. Anesth Analg. 2009;108:1902–9
25. Sessler DI, Kurz A, Saager L, Dalton JE. Operation timing and 30-day mortality after elective general surgery. Anesth Analg. 2011;113:1423–8
26. Kynes JM, Schildcrout JS, Hickson GB, Pichert JW, Han X, Ehrenfeld JM, Westlake MW, Catron T, Jacques PS. An analysis of risk factors for patient complaints about ambulatory anesthesiology care. Anesth Analg. 2013;116:1325–32
27. Kapur PA. Designing the future: insights from current supervisory models. Anesth Analg. 2013;116:749–51
28. Dexter F, Wachtel RE, Todd MM, Hindman BJ. The “fourth mission:” the time commitment of anesthesiology faculty for management is comparable to their time commitments to education, research, and indirect patient care. A&A Case Reports. 2015;5:206–11