Managing Patient Flow: Smoothing OR Schedule Can Ease Capacity Crunches, Researchers Say

This article appeared in the November 2003 edition of OR Manager, and is used with permission.
Emergency departments are over-crowded. Ambulances are going on diversion. ICU beds are overflowing.  Surgery is delayed.
Problems like these are stressing hospitals across the country. What's the answer?  Expand the ED? Add more ORs and ICU beds? Hire more staff? Perhaps. But there's another place to look  the elective surgical schedule. 
The variability of the elective schedule puts more strain on the system than the random cases that arrive through the emergency room. 
That's the surprising finding of new research. The finding is leading some hospitals to take a new look at how they schedule surgery and manage the flow of patients throughout their facilities. 
Smoothing the elective surgical schedule can avoid peaks and valleys that stress a hospital that is near capacity. 
Say, for example, the cardiac surgeons have block times on Wednesday and Thursday. When those patients come out of surgery, they go to the ICU. Soon those beds are full. There is no more room for patients who come in as emergencies, and the ED is placed on diversion. If the demand for ICU beds is high enough, some surgical patients may need to be held in the postanesthesia care unit. 
Evening out the surgery schedule can ease these capacity crunches. This can actually benefit the surgeons by allowing them to get more cases done and thus increase their revenue. 
The findings are from research by Eugene Litvak, PhD, director of the Program for the Management of Variability in Health Care Delivery and professor of health care and operations management at Boston University. 
In June, Dr Litvak and his colleagues, led by Michael McManus, MD, MPH, of Harvard Medical School, published a study conducted at Children's Hospital in Boston. They found that during the hospital's busiest times, nearly 70 percent of all of the diversions from the ICU were associated with variability in the scheduled caseload- when elective surgery peaked, so did the number of patients diverted from the ICU. 
A graph published with the study shows the results dramatically. The graph has two lines.  One line is the elective surgical demand. The second line is the number of patients diverted. The two lines nearly match.
"The graph shows that whenever we have a peak in demand in scheduled admissions, we usually have a peak in diversions from the ICU, with all of the consequences that brings in terms of quality," Dr Litvak told OR Manager. 
Impact of the OR schedule
What does that have to do with the OR? "You have two patient flows competing for hospital beds — ICU or patient floor beds," Dr Litvak explained. "The first flow is the scheduled admissions.  Most of them are surgical. The second flow is medical, usually patients admitted through the emergency department.
"So when you have a peak in elective surgical demand, all of a sudden, your resources are being consumed by those patients. You don't have enough beds to accommodate the medical demand." 
Not only do these peaks strain capacity, they can be a danger to patients, he contends. When surges occur, nurses are over-worked, and that makes errors more likely. The Joint Commission on Accreditation of Healthcare Organizations says 24 percent of sentinel events reported as of March 2002 were related to staffing levels. 
Though the study was conducted at a children's hospital, variability affects all hospitals that are operating near capacity, Dr. Litvak said. In fact, this hospital was one of the best he and his group have observed. He applauded Children's Hospital for allowing the data to be published and for being committed to addressing the cause of the problem. "Some other hospitals we observed were worse," he said. 
A huge ripple effect
Why do these peaks happen? It seems strange that scheduled admissions, such as elective surgery, have a bigger impact on variability than emergencies. "You would think that we call them scheduled admissions' because they are scheduled. In fact, they are more variable than random demand," Dr. Litvak said. 
In surgery, the variability is created by the block schedule. Peaks in these scheduled cases cause a "huge ripple effect for the entire hospital," he said. Dr. Litvak and Michael C. Long, MD, introduced the concept in a 2000 paper titled "Cost and quality under managed care," which created the scientific back-ground for the study. Typically, 80 percent or more of the variability from the OR is because of variations in the elective daily caseload  not as you would think from emergencies, cancellations, or add-on cases, they said.
Not only does the elective caseload vary from day to day each week, but it can vary by more than 50 percent on the same day of the week. The authors call this "artificial" variability because it isn't natural and random like emergency arrivals.
They propose that hospitals analyze the different kinds of variability in their systems and either eliminate them or manage them effectively. That, they argue, can make a big difference in the ability to manage all of the hospital more effectively.
Applying the research
Some hospitals are applying the research findings to smooth the flow of their surgical cases and make other changes. 
The Institute for Healthcare Improvement, Boston, is using Dr. Litvak's research in its Breakthrough project on optimizing patient flow in acute care hospitals. 
In smoothing surgical schedules, hospitals are using several approaches, which are described in accompanying articles:
  • Designating one or more ORs for add-on cases to help even out the variability from unscheduled cases.  St John's Hospital in Springfield, MO, has decreased waiting times for patients and even increased revenue for a group of surgeons using this method.
  • Shifting the block schedule to even out artificial demand created by surgical case scheduling. Boston Medical Center is addressing this huge project and other patient flow issues under a $250,000 grant from the Robert Wood Johnson Foundation.
The Variability Program at Boston University has developed software that can demonstrate the general principles of variability and patient flow. Modeling the effects on a particular hospital requires customizing the software. "Every place is different regarding the flow of patients," explains systems analyst and faculty member Abbot Cooper, and hospitals' information systems typically don't collect the type of information needed for modeling.
Managing patient flow: Smoothing OR schedule can ease capacity crunches, researchers say. OR Manager. Nov 2003;19:1,9-10.
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