Creating an optimal operating room schedule

AORN Journal,  March, 2005  by Murray V. Calichman

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Every hospital should develop an OR schedule that will ensure smooth patient flow to, through, and from the OR. This schedule should comply with all operating constraints, balance the demand for surgical beds with the hospital's supply of beds, and generate the maximum profit or revenue from each of those beds. One method surgical services managers can employ to achieve such a patient schedule is optimal OR scheduling.

CREATING AN OR SCHEDULE

Optimal OR scheduling was developed in the late 1970s when a hospital administrator was looking for an OR schedule that would eliminate the need to cancel surgical procedures each week because there was an insufficient number of surgical beds available (ie, unoccupied) on the day patients were scheduled to arrive at the hospital, which usually was the day before surgery. After reviewing that hospital's bed use statistics, it was apparent that an OR schedule that minimized cancellations could be created because there were more unoccupied beds during the week than there were cancelled surgical procedures (ie, 18 cancellations per week on average). The key was to schedule surgical procedures on different days to minimize and balance the number of beds required each day.

A bed utilization review indicated that the hospital in question was occupied fully from Sunday night through Thursday night, but beds were significantly underused on both Friday and Saturday nights. The challenge was to design a schedule that would use every surgical bed in the hospital seven days a week and not use one bed more or less. Developing such a schedule would require relating OR procedures to bed use.

Although all data are important, determining the distribution of lengths of stay for each surgical category and being able to use those data was an essential step in deriving an optimal OR schedule for the hospital in question. The resulting OR schedule allowed the hospital to eliminate its 18 cancellations each week and increase its revenue by 3% because it gained almost full use of its beds each day of the week.

CHANGING PARAMETERS

The initial OR schedule was developed at a time when hospitals were reimbursed on a per diem basis. Unfortunately, soon after the implementation of optimal OR scheduling at the facility in question, there was a change in the greater hospital environment. Two events occurred that discouraged widespread distribution of the application to other facilities. The first was a change in reimbursement from per diem rates to diagnosis-related group rates. The second event was a change from inpatient reimbursement to outpatient reimbursement for many procedures. These events, which occurred within months of each other, significantly reduced census statistics at most hospitals. Hospitals that had utilization statistics in the mid-to-high 90s became hospitals with utilization statistics in the high 70s to low 80s. These events seemingly obviated the need for optimal OR scheduling because lack of beds was no longer an operational constraint.

A few years ago, another hospital requested a review of its OR schedule. This review indicated that little had changed--the hospital in question was developing its daily OR schedule based on OR time, and the OR suite was experiencing an imbalance between the supply of and demand for surgical beds. What did change was how the imbalance manifested. Surgical procedures no longer were cancelled the day before they were scheduled. Now, patients often were coming in early in the morning on the day of their surgery. On occasions when all the floor beds were occupied, which is a continuing problem in some facilities, patients found themselves recovering in the postanesthesia care unit (PACU) for extended hours, if not days. Other patients experienced early-morning gridlock in the OR and were not able to move into the PACU after surgery because beds were not available. Still other patients had their procedures cancelled, although to a much lesser extent than what had occurred previously.

To minimize these operational problems, it was imperative that the OR schedule result in a balance between the need for floor beds and the supply of floor beds seven days each week; however, because many hospitals do not run a full OR schedule on Saturday, there are days when surgical beds will not be needed, even under this optimization approach. In addition, in hospitals without designated medical or surgical beds, the methodology will determine the minimum number of surgical beds required to bring it in balance with OR activity.

DERIVING AN OR SCHEDULE

To derive an optimal OR schedule for a surgical facility, it is important to gather appropriate data, use them to relate unknowns to the facility's operational constraints, and determine what is to be maximized (eg, profit, total revenue, number of procedures, number of patient days). It also is important to enter scheduling data on a computerized spreadsheet and analyze them using features available in most commercial spreadsheet software. Users can follow sequential steps.