Operating room efficiency

Operating Room Efficiency
Operating room (OR) efficiency is a measure of how well time and resources are used for their intended purposes. One way to analyze efficiency is to chart under-utilized and over-utilized time spent on a given day in the operating room. If the cases in an operating room finish earlier then scheduled, time is under-utilized. Likewise, if the cases in an operating room run "late" or past its allotted operating room time then this produces over-utilized time. .

The terms operating room utilization and operating room productivity are also often used when discussing operating room management of a surgical suite.

Performance Dashboard for a Surgical Suite:
An operating room manager must select criteria, or a dashboard of measurements, to assess overall functioning of a surgical suite. An example of an analytic tool used to rate surgical suites is reflected below. The examiner created a scoring system in order to quantify the efficiency levels of surgical suites.

OR efficiency measurements

The above objective criteria can be computed from data commonly available in hospital adminstrative data systems.

Excess staffing costs:
Nothing is more important than to first allocate the right amount of OR time to each service on each day of the week for their case scheduling. This is not the same as the block time! To illustrate this imagine that two cases each lasting 2 hours are scheduled into OR #1 with OR nurses and an anesthesiologist scheduled to work an 8 hr day. The matching of workload to staffing has been so poor that little can be done the day of surgery to increase the efficiency of use of the staff. Neither awakening patients more quickly nor reducing the turnover time, for example, will compensate for the poor initial choice of staffing for OR #1 and/or how the cases were scheduled into OR #1.

Optimal allocation of OR time should be based on historical use by a particular service (i.e., unit of OR allocation such as surgeon, group, department, or specialty) and then using computer software to minimize the amount of underutilized time and the more expensive overutilized time. Under-utilized hours reflect how early the room finishes. In the example above, if staff were scheduled to work from 7:00 AM to 3:00 PM and instead the room finished at 11 AM, then there would be 4 hrs of underutilized time. The excess staffing cost would be 50% (4hrs/8hrs). On the other hand, if 9 hrs of cases are performed in an OR with staff scheduled to work 8 hrs then the excess staffing cost is 25%. Over-utilized hours are the hours that ORs run longer than the regularly scheduled OR hours, or 1 hr in this example. 1hr/8hr=12.5% which is then multiplied by the additional cost of staying late which often is assumed to be a factor of two (related to monetary overtime cost paid to staff, as well as recruitment and retention costs related to unhappy staff because they have to stay late unpredictably). OR suites can reasonably aim to achieve a staffing cost that is within 10% of optimal (i.e., workload is perfectly matched to staffing).

If the key is to allocate appropriate time to each service based on historical OR use, how do you deal with rooms consistently running late on the day of surgery? The answer: make the allocated time, into which cases are being scheduled, longer. For example, if a surgeon does 12 hrs worth of cases every day he is in the OR, don’t plan 8 hrs of staffing (7am-3pm) and have everyone frustrated by having to stay late (overtime). Rather, schedule his cases into 12 hrs of allocated time (7am-7pm). That way, anesthesia and nursing staff know they will be there 12hrs when they arrive to work and overtime costs (financial and morale) will be reduced. The common response to this approach is, “No one wants to be there till 7 pm.” The answer to that is, “You are there now till 7 pm so why not make scheduled OR time 12 hr long and have a more predictable work day duration.” Thus, optimizing staffing costs is finding balance between overtime and finishing early.

There may be concern about a nurse manager's ability to flex the staff enough to avoid excess staffing costs. It can be difficult from a human resources standpoint to match scheduled cases with staffing perfectly, such that staff still get the hours and shifts they need. For example, if Dr Smith needs a 12-hour block, the manager needs to find staff who want to work a 12-hour shift (or part-timers in some combination). Staffing is not only an OR efficiency issue, but a staff satisfaction issue. It can be a challenge at a time when recruiting and retaining nurses are growing concerns.

Start-time tardiness: (mean tardiness of start times for elective cases per OR per day)
Reducing the time patients have to wait for their surgery once they arrive to the hospital (especially if the preceding case runs late) is another important goal for the OR manager. If a case is supposed to start at 10:00 AM (patient enters OR), but the case starts at 10:30 AM instead, then there are 30 minutes of tardiness. In computing this metric, no credit is given if the 10:00 AM case starts early (for example at 9:45 AM).

The tardiness of start of scheduled cases should total less than 45 mins per eight hour OR day in well functioning OR suites. Facilities with long work days will have greater tardiness because the longer the day, the more uncertainty about case start times. Having patients’ medical records ready to go with all needed documents is essential for on time starts.

Case cancellation rate on day of surgery:
Cancellation rates vary among facilities, depending partly on the types of patients receiving care, ranging from 4.6% for outpatients, to 13% -18% at VA medical centers. Many cancellations are due to non-medical problems such as a full ICU, surgeon unavailability, or bad weather. OR cancellation rates can be monitored statistically. Well functioning OR suites should have cancellation rates less than 5%. Monitoring the cancellations correctly is not taking the ratio of the number of cancellations to the number of scheduled cases.

PACU admission delays: (% of workdays with at least one delay of 10 mins or greater in PACU admission because PACU is full)
It is important to adjust PACU nurse staffing around the times of OR admissions. Algorithms exist that use the number of available nursing hours to find the staffing solution with the fewest number of understaffed days.

Contribution margin (mean) per OR hour:
An OR suite that puts up with excessive surgical times can schedule itself efficiently but still lose its financial shirt if many surgeons are slow, use too many instruments, or expensive implants, etc. These are all measured by the contribution margin per OR hr. The contribution margin per hour of OR time is the hospital revenue generated by a surgical case, less all the hospitalization variable labor and supply costs. Variable costs, such as implants, vary directly with the volume of cases performed.

This is because fee-for-service hospitals have a positive contribution margin for almost all elective cases mostly due to a large percentage of OR costs being fixed. For USA hospitals not on a fixed annual budget, contribution margin per OR hour averages one to two thousand USD per OR hour.

Turnover times:
Turnover time is the time from when one patient exits an OR until the next patient enters the same OR. Turnover times include cleanup times and setup times, but not delays between cases. Based on data collected at 31 USA hospitals, turnover times at the best performing OR suites average less than 25 mins. Cost reduction from reducing turnover times (because OR workload is less) can only be achieved if OR allocations and staffing are reduced. Despite this, turnover time receives lots of attention from OR managers because it is a key satisfier for surgeons.

Sometimes the OR suite reduces turnover times (by providing more staff to clean the room for example) but new problems arise (not enough time for sterilizing instruments for the new case, can’t bring patient to PACU because no beds) that were “hidden” by long turnover times.

Times between cases that are longer than a defined interval (e.g., 1 hr because to follow surgeon is unavailable) should be considered delays, not turnovers.

Prediction bias: (Bias in case duration estimates per 8 hr of OR time)
Prediction error equals the actual duration of the new case minus the estimated duration of the new case. Bias indicates whether the estimate is consistently too high or consistently too low, and precision reflects the magnitudes of the errors of the estimates. Efficient OR suites should aim to have bias in case duration estimates per 8 hr of OR time that is less than 15 minutes. A reason for bias can be surgeons’ consistently shortening their case duration estimates because they have too little OR time allocated and need to “fit” their list of cases into the OR time they do have. In contrast, other OR suites may have surgeons that purposely overestimate case durations to keep control/access of their allocated OR time so that if a new case appears their OR time was not given away.

Remember that lack of historical case duration data for scheduled procedures is an important cause of inaccuracy in predicting case durations. In general, half of the cases scheduled in your OR suite tomorrow will have less than five previous cases of the same procedure type and same surgeon during the preceding year.

It would be nice to have no uncertainty in case duration prediction. But, it is present. The problem is looking for a single number that is correct most of the time. You won't get accurate estimates by using historical case duration data. Rather, from the historical data you'll get an assessment of the uncertainty.

Prolonged turnovers:
Times between cases that are longer than a defined interval (e.g., 1 hr because to follow surgeon is unavailable) should be considered delays, not turnovers.