THIS issue of Anesthesiology includes three articles describing the use of overlapping anesthesia induction to perform more cases in a regular workday.1–3The purpose of my article is to assist readers in deciding whether the studied interventions would increase productivity (work completed per $cost) in their operating rooms (ORs). The three articles used induction rooms slightly differently. The details are of large practical importance, because simply stating that induction rooms were used does not capture the issues of staffing and patient flow. Nevertheless, I leave such details to readers, because they are straightforward. If the recipe is followed, likely most any facility will achieve the same reported reductions in nonoperative times. In contrast, whether such reductions in anesthesia-controlled and turnover times will result in an increase in productivity varies markedly among practice settings. Results are highly sensitive to how OR time is allocated and cases are scheduled. While considering the examples, • Hospital A: Fixed hours of OR time, add-on cases not used to fill ORs • Hospital B: Fixed hours of OR time, add-on cases used to fill ORs • Hospital C: Surgeon open access to OR time, more than 8 h of cases a day • Outpatient A: Surgeon open access to OR time, less than 8 h of cases a day • Outpatient B: Fixed hours of OR time, you may consider your situation to be a combination of examples. If so, I will have succeeded at showing why quantitative methods to consider the balances automatically4are important tools for OR and anesthesia group management. A surgeon sees patients and operates on them in the next available opening. Patients wait on average 3.5 weeks for surgery. Occasionally, from the random ebb and flow of patients and/or the surgeon's vacation, the surgeon's queue extends to 6 weeks. The surgeon has allocated OR time Mondays from 7:00 am to 3:00 pm. The OR finishes at • 10th percentile 1:00 pm • 25th percentile 1:15 pm • 50th percentile 1:50 pm • 66th percentile 2:00 pm • 80th percentile 2:20 pm • 90th percentile 3:00 pm. The surgeon has few short cases that can fill the remaining OR time at the end of the day in the OR. Also, whether the last case would be performed would be unpredictable, because on the day of surgery, if a case would not be expected to finish by 3:00 pm, the case is cancelled, resulting in patient inconvenience and frustration. The managers focus on preventing overutilized OR time. United States readers should appreciate that, at Hospital A, OR time is not being allocated (i.e. , staffing is not being adjusted) based on OR workload. The surgeon is thankful for the 8 h of OR time budgeted to him or her by the hospital, not vice versa . On a long-term (e.g. , 1 yr) basis, more OR time may be budgeted, but that is irrelevant to the issue at hand. Hanss et al. 1showed that for Hospital A, the use of overlapping induction can reduce anesthesia-controlled and turnover times sufficiently for an extra, brief (< 1.5 h) case of another surgeon to be performed each day. This applies provided patients are admitted or are otherwise available to have surgery only if there is a sufficient reduction in time that day for the case.1 Hospital B matches A, except that managers try to fill remaining OR time with cases. Managers keep lists of potential add-on cases, both inpatients and outpatients available to be contacted the day before surgery. As many hours of these add-on cases as possible are scheduled.5,6An extrashort case can fit at the end of the day in each of several ORs.5,7Thus, remaining, unscheduled add-on cases are relatively long (i.e. , > 2 h). At Hospital B, the use of overlapping induction may not result in a sufficient reduction in anesthesia controlled and turover times to be able to perform additional cases.7Hospital A matches that described by Hanss et al. 1in that their underutilized OR time averaged 1.9 h per OR per day. Because their newly scheduled cases had OR times of less than 1.5 h,1some of those cases could have been scheduled without the use of overlapping induction. Anesthesia providers at Hospital A should focus first at converting OR scheduling to that of Hospital B and then make efforts to initiate overlapping anesthesia induction. This applies particularly to anesthesia providers who work at but are not employed by Hospital A. Sandberg et al. 3showed that the successful use of overlapping induction to increase productivity results in a benefit to patients and surgeons, with no overall change in hospital plus anesthesia net margin. Yet, overlapping induction increased anesthesia providers' costs by 21%, with no increase in revenues.3In contrast, changing case scheduling causes no increase in costs, and an increase5in revenue for hospital and anesthesia providers. A surgeon sees patients in the clinic on Tuesdays and performs surgery on them typically 6 days later. Depending on the need for medical evaluations, insurance approval, and so forth, surgery is sometimes 13 days later. The surgeon's cases enter the OR at 7:00 am. Finish times are • 10th percentile 1:00 pm • 25th percentile 2:00 pm • 50th percentile 3:00 pm • 66th percentile 5:00 pm • 80th percentile 6:00 pm • 90th percentile 7:00 pm. The OR workload varies a lot, depending on the random arrival of patients' requests for surgery. The surgeon sometimes has two cases and sometimes has four. At Hospital C, managers allocate OR time on a short-term basis (i.e. , adjust staffing) based on OR efficiency, to provide the surgeon with the right amount of OR time, neither too much nor too little.4,8Managers consider the ratio of the cost of 1 h of overutilized OR time to 1 allocated hour to be 2:1. Thus, one third of allocated ORs should finish late, and two thirds should finish early. Staffing for the 66th percentile (i.e. , two thirds) provides the surgeon with an allocation Mondays from 7:00 am to 5:00 pm.9For days when the surgeon finishes after 5 pm, staff sign up months in advance to work late if needed, being paid overtime (OR nurses) and bonuses (anesthesiologists). The use of overlapping induction is unlikely to increase the number of cases performed during allocated (scheduled) hours at Hospital C, because there are no additional cases to be performed. I designed the scenario to show that overlapping induction can still increase productivity by reducing the costs to perform the existing cases. The OR workload could be reduced sufficiently for the surgeon to be allocated 8 h instead of 10 h for the same cases.4,8 The return on investment in implementing overlapping induction depends on the proportion of ORs for which OR allocation could be reduced. Cost reduction is achievable when there are many services allocated, at baseline, more than 10 h of OR time on a workday.8Frequently there are not.4,8Also, managers need to judge whether allocated OR time would be reduced or remain the same because of organizational (political) resistance to change. The impact of reducing turnover and anesthesia-controlled times on costs depends on the differences between actual and scheduled OR times,10,11variability among days in the surgeons' workload,4,8absolute workload,4,8and the number of turnover times to be reduced.3,11The result can be determined by analyzing a facility's OR and anesthesia information system data. I have not determined a way to guess answers, because findings differ among surgeons, groups, and departments at the same facility.3,8Generally, the more the variability is, the less the benefit is, whereas the more the workload and the turnovers are, the larger the benefit is. If a surgeon, group, or specialty completely fills (> 8 h) an OR every Tuesday with many short cases, large reductions in turnovers and anesthesia-controlled times can result in increased productivity. For example, consider Surgeons 1 and 2 in the article by Sandberg et al. 3Surgeon 1's workload was reduced from 8.9 h to 8.5 h and averaged one turnover per day. In contrast, Surgeon 2's workload started at 9.9 h and was reduced more, to 8.7 h, because the surgeon averaged four turnovers per day. To understand why day-to-day variability in workload matters, suppose that on half of the workdays, Surgeon 2 had averaged 4 h of cases, and on the other half did 15.8 h of cases in two ORs each staffed for 10 h. Then, there would be no cost benefit to reducing turnover and anesthesia-controlled times. The scenario at Hospital C applies to hospitals for their medically urgent cases. The cases must be performed. Of course, in that setting, reducing turnover and anesthesia-controlled time can result in an additional case being performed during the regular workday (e.g. , 7 am to 3 pm), provided the reduction in time is large enough and the additional case is short enough.2The question whose answer will vary among hospitals is whether such a reduction in turnover and anesthesia-controlled time results in a net increase or reduction in costs (i.e. , increases productivity). I have not mentioned the issue of the surgeon who often schedules to work slightly more than 8 h but chooses on his or her own not to work longer hours. In other words, the bottleneck is not the day-to-day variability in workload or the hospital and anesthesia providers, but the surgeons' desire to work late. These circumstances differ from those of previous studies that my colleagues and I have performed showing the relative lack of impact of reducing turnover and anesthesia-controlled times on performing an additional case(s).4,11Unlike in our previous studies, OR time is not fixed, meaning that if a case is scheduled, it is performed even if it would run late on any one day. This is why the findings of Surgeons 3 and 4 in Sandberg et al. 3and the urgent cases in Torkki et al. 2were expected. Surely, reducing turnover and anesthesia-controlled times can result in performing additional cases during the workday. Neither article showed an increase in productivity (work completed per$ cost) in this setting, only the potential for it to occur.

A surgeon operates at Outpatient A every Friday from 7:00 am until

• 10th percentile 1:00 pm

• 25th percentile 1:30 pm

• 50th percentile 1:55 pm

• 66th percentile 2:10 pm

• 80th percentile 2:30 pm

• 90th percentile 3:00 pm.

Managers consider this adjusted utilization of 86% to be good, because many surgeons' allocated OR times are less than 60%.

Like Hospital C, at Outpatient A, the surgeon limits OR workload, not availability of OR time. If the surgeon brought more cases to the facility, staffing would be adjusted to fit the workload. Because often that would mean finishing after 3:00 pm, managers may encourage the surgeon to operate on another day. However, that is irrelevant to the issue at hand. The premise of OR allocation would be to match staffing to the surgeon's workload, not vice versa .

If there were a direct effect of the use of overlapping anesthesia induction on productivity at Outpatient A, it would be by reducing labor costs. However, reducing turnover and anesthesia-controlled times cannot result in reduced overutilized OR time in this scenario, because there is no overutilized OR time.4,8Allocated hours cannot be reduced, because the surgeon will still have the staffed OR for the day. Labor costs and anesthesia staffing are a fixed cost of the number of staffed ORs (i.e. , the first case of the day starts).

Gynecologists share allocated OR time at Outpatient B on Fridays. They do many brief cases. They have an adjusted utilization of 92%. They have a patient queue of 7 weeks. The limits on their incomes are not their personal work hours, but the lack of OR time.

The use of overlapping induction may increase the number of patients treated by the gynecologists, but it may not. The key issue is whether there are sufficient outpatients who would be satisfied to be told that they can have their surgery in fewer days if they were to receive care within one of a few consecutive afternoons. A fundamental feature of the intervention of Hanss et al.  1was to have patients available who would have surgery on an ad hoc  basis. If patients must be scheduled reliably, reducing the anesthesia-controlled and turnover times may not result in completion of additional cases.11Because of large mean absolute differences between scheduled and actual case durations for surgery, large reductions in time are needed to schedule an extra case into an OR reliably .11

Readers would miss an important point if they look at the clinical trial of Hanss et al.  1as just one of overlapping induction of anesthesia. At facilities for which lack of OR time limits patient care, do everything you can to resist or change the paradigm that patients have to know within a few days of surgery when they will have surgery. The availability of a pool of patients who are flexible, in exchange for receiving prompt care, may be fruitful.

The three articles in this issue of Anesthesiology study different situations. Hanss et al.  1consider fixed hours of OR time, with cases performed only when the OR time was reduced. Torkki et al.  2studied medically urgent orthopedic trauma patients, wherein all cases were performed, the issue being the time of the day when done. Sandberg et al.  3studied increases in cases when limited by the surgeons or longer-term institutional culture. Provocatively, none of these scenarios overlap with the conditions studied by previous investigations of the impact on productivity of reducing turnover and anesthesia-controlled times.4,7,11

The University of Iowa, Iowa City, Iowa. franklin-dexter@uiowa.edu

1.
Hanss R, Buttgereit B, Tonner PH, Bein B, Schleppers A, Steinfath M, Scholz J, Bauer M: Overlapping induction of anesthesia: An analysis of benefits and costs. Anesthesiology 2005; 103:391–400
2.
Torkki PM, Marjamaa RA, Torkki MI, Kallio PE, Kirvelä OA: Use of anesthesia induction rooms can increase the number of urgent orthopedic cases completed within 7 hours. Anesthesiology 2005; 103:401–5
3.
Sandberg WS, Daily B, Egan M, Stahl JE, Goldman JM, Wiklund RA, Rattner D: Deliberate perioperative systems design improves operating room throughput. Anesthesiology 2005; 103:406–18
4.
Dexter F, Abouleish AE, Epstein RH, Whitten CW, Lubarsky DA: Use of operating room information system data to predict the impact of reducing turnover times on staffing costs. Anesth Analg 2003; 97:1119–1126
5.
Dexter F, Macario A, Traub RD: Which algorithm for scheduling add-on elective cases maximizes operating room utilization? Use of bin packing algorithms and fuzzy constraints in operating room management. Anesthesiology 1999; 91:1491–500
6.
Dexter F, Epstein RD, Traub RD, Xiao Y: Making management decisions on the day of surgery based on operating room efficiency and patient waiting times. Anesthesiology 2004; 101:1444–53
7.
Dexter F, Macario A: Decrease in case duration required to complete an additional case during regularly scheduled hours in an operating room suite: A computer simulation study. Anesth Analg 1999; 88:72–6
8.
Abouleish AE, Dexter F, Whitten CW, Zavaleta JR, Prough DS: Quantifying net staffing costs due to longer-than-average surgical case durations. Anesthesiology 2004; 100:403–12
9.
Strum DP, Vargas LG, May JH: Surgical subspecialty block utilization and capacity planning: A minimal cost analysis model. Anesthesiology 1999; 90:1176–85
10.
Dexter F, Macario A, Manberg PJ, Lubarsky DA: Computer simulation to determine how rapid anesthetic recovery protocols to decrease the time for emergence or increase the phase I post anesthesia care unit bypass rate affect staffing of an ambulatory surgery center. Anesth Analg 1999; 88:1053–63
11.
Dexter F, Coffin S, Tinker JH: Decreases in anesthesia-controlled time cannot permit one additional surgical operation to be scheduled during the workday. Anesth Analg 1995; 81:1263–8