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ECONOMICS, EDUCATION, AND HEALTH SYSTEMS RESEARCH

Inclusion of Turnover Time Does Not Influence Identification of Surgical Services that Over- and Underutilize Allocated Block Time

Amr E. Abouleish, MD MBA^*, Sharon L. Hensley, RN, Mark H. Zornow, MD^*, and Donald S. Prough, MD^*

*Department of Anesthesiology, University of Texas Medical Branch; and Department of Nursing, John Sealy Hospital, Galveston, Texas

Address correspondence and reprint requests to Amr E. Abouleish, MD, MBA, Department of Anesthesiology, The University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0591. Address e-mail to aaboulei{at}utmb.edu

	Abstract

Top Abstract Introduction Materials and Methods Results Discussion References

 
Allocation of operating room (OR) block time is an ongoing challenge for OR managers. In this study, we sought to determine whether inclusion or exclusion of turnover time in comparisons of block utilization would identify different surgical services as under- or overused. For a 13-mo period, we evaluated data extracted from the OR information system of a large academic medical center. During that time period, 15 surgical services performed 12,245 surgical procedures. Allocated block hours, number of first cases performed, total number of cases, and average case durations were determined. The average turnover time for each service was determined by a manual, case-by-case review of data from 1 mo. Raw utilization (RU; case durations only) and adjusted utilization (AU; case duration plus turnover time) were calculated for each service. Turnover time was credited to the service performing surgery after room turnover. Case du-ration was limited to surgeries performed during resource hours. Two indices of utilization (i.e., the usage rate of the service divided by the overall use of all ORs in the suite) were used to compare services: the RU or AU Index (RUI or AUI). Outliers were services with indices that were >1.15 or <0.85. The RUI identified three services as underutilizers and one service as an overutilizer. Using the AUI, the same outliers were identified, and no new services were identified. Examining the changes in index (between AUI and RUI), the percentage of to-follow cases highly correlated with changes in index (r² = 0.60); the average turnover time did not (r² = 0.002). Inclusion of turnover time did not change the services that were identified as under- and overutilizer.

IMPLICATIONS: Turnover time is difficult to determine from existing operating room information systems. This study determined the use of block time with and without turnover time for each surgical service in a large academic hospital. Turnover time did not change identification of surgical services that over- (one service) or underused (three services) allocated block time.

	Introduction

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Allocation of block time and first starting times in operating rooms (ORs) is a major challenge for OR managers and anesthesiology groups. Ideally, continuing evaluation of the allocation and start times should be performed and discussed with surgeons, nursing staff, and the anesthesiology group members. However, the methods by which utilization of time and OR allocation are conducted may influence the results of the evaluation as well as the acceptance of those results by surgeons, nursing staff, and anesthesiologists.

One common methodological decision that must be made when attempting to determine utilization is whether to include or exclude room turnover time. Although methods of allocating block time and surgical case scheduling to maximize efficiency or minimize costs have been described (1–6), there is no consistent management of turnover times in the existing methodologies. Issues surrounding inclusion or exclusion of turnover time include which service should be credited with the turnover time (the preceding or following service, if different) and how to credit a long turnover time (e.g., >60 min). Therefore, the inclusion of turnover time can be viewed as advantageous or disadvantageous by individual services.

As a general concept, OR utilization can be calculated as the percentage of time that a service uses allocated OR time. By definition, if turnover time is included in the determination of allocated time, the percentage used will be larger for all services, thus increasing the percentage of overall OR utilization, as well. As a result, if inclusion of turnover time increases one service’s utilization more than that of another service, the first service will consider inclusion of turnover time as advantageous, whereas the second service will not.

Currently, OR information systems (IS) record a large amount of data regarding times of events in the OR suite, including overall time (time exiting an OR after surgery [out-room] minus time entering the room before surgery [in-room]). Unfortunately, time between cases (turnover time) is not easily determined from the data contained in an OR IS. Therefore, if turnover time does not make a difference in determining whether surgical services are over- or underutilizing allocated block time, reporting utilization without turnover time will be simpler.

In this study, we examined the utilization of allocated block OR time by surgical services with and without the inclusion of turnover time. The purpose of the study was to determine whether or not the inclusion of turnover time changed the identification of which services over- or underutilized block time as compared with other surgical services.

	Materials and Methods

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Data were collected from the OR IS of a large academic medical center hospital for surgical cases performed between February 1, 2000, and February 28, 2001. Information for each case included day of week and date of care, patient in-room time, patient out-room time, and surgical service providing care. Surgical service was defined as those services that were allocated block time. Definitions of terminology are summarized in Table 1 (7).

The total case duration for a service was calculated by summing the time that patients were in ORs during resource hours. Surgeries performed outside established resource hours were not included. All cases performed by a service inside or outside of their allocated blocks (but within resource hours) were credited to the service performing the surgery. For example, if Service A performed surgery until 1 PM of their block time and Service B performed surgery to follow for 2 h, the to-follow case duration was credited to Service B.

Total OR time included both case durations and turnover times. Because turnover time could not be accurately determined from the OR IS, average turnover time per service was determined through a manual, case-by-case review of the OR schedule for the month of January 2001 and was assumed to be representative for the entire 13-mo period. For cases other than the first case of the day, turnover time was assigned to the surgical service that used the room after the turnover. For example, if on a given day Surgical Service A had one case at the beginning of the day followed by two cases by Surgical Service B, then both turnover times would be credited to Surgical Service B. No turnover time would be credited to Surgery A for that OR on that day. Finally, turnover times >75 min were excluded in the determination of average turnover time per service because of the assumption that times exceeding 75 min included idle OR time and thus could not be attributed to clean-up and set-up.

The average turnover time per service was then added to the case durations to determine the total OR time for the 13-mo time period. The total turnover time per service was equal to:

where to-follow cases equaled the total number of cases minus the number of first-start cases.

Raw utilization (RU) was determined by dividing the total case durations by the allocated block time. Adjusted utilization (AU) was calculated by dividing total OR time (case durations + turnover time) by allocated block time. Both RU and AU were determined for each service and for the OR suite as a whole. The RU Index (RUI) was determined for each service by dividing the RU for the service by RU of the whole OR suite. Similarly, the AU Index (AUI) was determined for each service by dividing the AU for the service by the AU of the whole OR suite.

To evaluate what factors might influence any difference between the RUI and AUI, several other mea-surements were calculated. Average case duration per service was determined by dividing total case duration by the total number of cases. The percentage of to-follow cases was calculated by dividing all cases (other than first-start cases) by total cases.

Mean and SD were reported for the measurements calculated. Services were defined as outliers for utilization if either their RUI or AUI was outside the range of 0.85–1.15. Pearson correlation was performed between factors considered likely to influence differences between RUI and AUI.

	Results

Top Abstract Introduction Materials and Methods Results Discussion References

 
The OR IS identified 12,245 surgical cases that were performed for the 13-mo period by 15 different surgical services. The data used to calculate the RUI and AUI are shown in Table 2. The large variation of AM starts (mean + SD) and the number of overall cases per service reflect differences in allocated block OR time (mean + SD). In contrast, average turnover time varied less and was independent of allocated block time (correlation, r² < 0.01). Turnover time, the time spent cleaning up after the previous case and setting up for the next case, was longest for cardiothoracic surgery (63 min), with the burn service having the next longest time (52 min). In contrast, ophthalmology and plastic surgery had the smallest turnover times (21 and 28 min, respectively).

View larger version (44K): [in this window] [in a new window]   Figure 1. Raw Utilization Index (RUI) and Adjusted Utilization Index (AUI) by surgical service. Outliers of block utilization were defined as RUI or AUI <0.85 or >1.15. The same services were identified as outliers (*) when turnover time was included (AUI) or excluded (RUI). Data collected during a 13-mo period (February 2000 to February 2001).

View larger version (17K): [in this window] [in a new window]   Figure 2. Percentage change in use index Adjusted Utilization Index and Raw Utilization Index (AUI–RUI)/RUI) correlates with percentage of to-follow cases for surgical services. The larger percentage of to-follow cases accounts for most of the change in the utilization index (r2 = 0.60). Percentage of to-follow cases negatively correlates with average case duration (r2 = 0.76), i.e., the shorter the cases, the more cases can be performed in 1 day. Data collected during a 13-mo period (February 2000 to February 2001). Means are unweighted.

	Discussion

Top Abstract Introduction Materials and Methods Results Discussion References

 
In this analysis, calculation of RUI and AUI facilitated comparison of usage rates among surgical services. By defining overutilization and underutilization using arbitrary levels of 15% more or less than the mean (RUI or AUI >1.15 or <0.85), we identified the same surgical services as outliers. We therefore conclude that including turnover time is not helpful in determining utilization. This observation is advantageous because of the difficulty in measuring turnover time using current OR IS and the controversy regarding the method of calculating turnover time.

The question of whether to assign turnover time to preceding or succeeding cases may be controversial. A surgical service that performs cases throughout each of its block-scheduled days would no doubt prefer that turnover time be included in its overall usage rates because this would maximize the absolute percentage of utilization of block time. In contrast, surgical services that perform many first-start cases that are followed by other surgical services would surely prefer that turnover time be assigned to the preceding services. Likewise, those services that perform large numbers of cases that follow cases performed by other surgical services would undoubtedly agree with the methodology in this paper, which assigned turnover time to the following service.

Differing durations of clean-up after different types of procedures (e.g., cardiac surgery versus ophthalmology) might also complicate calculations. Therefore, both methodologies of assigning turnover time are arbitrary. Perhaps an ideal system would vary assignment based on the type of both the first-start and following surgery. For instance, if the first case of the day were to be a burn debridement or major trauma, and this case were to be followed by an inguinal herniorrhaphy, then the longer clean-up time occasioned by burn and trauma surgery would argue that most of the turnover time should be credited to the first service. In contrast, if the first case were to be an inguinal herniorrhaphy that was to be followed by an on-bypass cardiac procedure, then the longer set-up time for the second case would argue for assignment of turnover time to the following service.

We chose to assign turnover time to the following services because of the following argument. We considered it irrational to assign an arbitrary (and imaginary) time for turnover after the final case in an OR. By inference, then, turnover time preceding the final case should be assigned to that case and not to the next-to-last case. Using this chain of logic, turnover time would be assigned to every case in one OR other than the first-start case, for which there would be no preceding turnover time. However, this arbitrary approach would require reassessment by the OR managers of any institutions seeking to implement it.

Another problem with calculating turnover time for purposes of assigning block time involves the presence of excessive intervals between cases. We assumed that turnover time accounts for all of the time associated with these periods of inactivity. For example, idle time, such as that consumed waiting for intrahospital transport of patients, may increase time between cases but is not attributable to members of the surgical team. In this study, we limited turnover times to 75 minutes for purposes of calculating average turnover time; other investigators have used turnover times of 60 minutes (5). Because current OR IS cannot as easily determine turnover times for specific surgical services as ORs, especially in comparison to the relatively easy task of determining case duration, we consider it practical to exclude turnover time in identifying over- and underutilizers for purposes of allocating block time.

In this study, turnover time did not change the recognition of over- and underutilizing services. However, more than half of the surgical services studied had more than a 5% difference between RUI and AUI (Table 4). The actual length of turnover time did not correlate with the percentage change between RUI and AUI. However, case duration negatively correlated and percentage of to-follow cases correlated highly with percentage change between RUI and AUI. This finding supports the clinical impression that the addition of small increments of turnover time exerts minor effects on the utilization of ORs in which cases of long duration are performed but relatively large effects on the utilization of ORs in which many cases of short duration are performed. For example, in this study, AUI exceeded RUI by the largest percentage in three of the four services (pediatric, general surgery A, and urology) in which case duration was two hours. Each of these three services had average turnover times, whereas the fourth service (ophthalmology) had the shortest turnover time. The RUI and AUI were similar for ophthalmology because of the combination of short turnover time and short surgical time.

Surgical durations outside of resource hours were not included because the study focused on allocated block time. If block time were to be allocated for evenings, weekends, or holidays, then it would be appropriate to include these in the analysis. However, in the OR suite studied, block time did not include these times. This methodology will reduce the total case durations of surgical services that perform substantial numbers of nonemergent surgical procedures outside of resource hours. If block utilization is the sole measurement of OR activity, then those surgical services will not be recognized as potentially requiring additional block time. The current analysis is limited to only identifying over- or underutilization of allocated block time and does not address allocation of block time. Previous studies have demonstrated that assigning block time on the basis of case durations will not lead to the most cost-efficient results (3–6). This study also does not address the issues of overtime or the staffing of cases performed. Further, if revenue is considered, then allocation of block time will not be based strictly on utilization (8). However, despite the limited scope of this study, the methodology and results address a common question faced by OR managers: who must determine how to allocate and evaluate block time?

In this study, the inclusion of turnover time did not alter the identification of services that over- or underutilized allocated block time. Therefore, we suggest that turnover time not be included in identifying over- and underutilizing surgical services, although each OR management team should consider this decision based on their individual circumstances.

	Acknowledgments

 
The authors wish to thank Jordan Kicklighter, BA (Editor, Anesthesiology Editorial Office), and Irela Salinas, AA (Editorial Assistant, Anesthesiology Editorial Office), in the Department of Anesthesiology at The University of Texas Medical Branch for preparing and editing this manuscript.

	Footnotes

 
Presented at the 54th Annual Meeting of the American Society of Anesthesiologists, New Orleans, Louisiana, October 13–17, 2001.

	References

Top Abstract Introduction Materials and Methods Results Discussion References

 

1. Mazzei WJ. Operating room start times and turnover times in a university hospital. J Clin Anesth 1994; 6: 405–8.[Web of Science][Medline]
2. Prough DS, Jenkins D, Yancy V, Duncan R. Improving operating room efficiency: a sisyphean task? Problems in Anesthesia 1998; 10: 373–94.
3. Strum DP, Vargas LG, May JH. Surgical subspecialty block utilization and capacity planning: a minimal cost analysis model. Anesthesiology 1999; 90: 1176–85.[Web of Science][Medline]
4. Dexter F, Macario A, Traub RD, et al. An operating room scheduling strategy to maximize the use of operating room block time: computer simulation of patient scheduling and survey of patients’ preferences for surgical waiting time. Anesth Analg 1999; 89: 7–20.[Abstract/Free Full Text]
5. 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.[Web of Science][Medline]
6. Dexter F, Traub RD. How to schedule elective surgical cases into specific operating rooms to maximize the efficiency of use of operating room time. Anesth Analg 2002; 94: 933–42.[Abstract/Free Full Text]
7. Donham RT. Defining measurable OR-PR scheduling, efficiency, and utilization data elements: the Association of Anesthesia Clinical Directors procedural times glossary. Int Anesthesiol Clin 1998; 36: 15–29.[Web of Science][Medline]
8. Macario A, Dexter F, Traub RD. Hospital profitability per hour of operating room time can vary among surgeons. Anesth Analg 2001; 93: 669–75.[Abstract/Free Full Text]

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