"There is much speculation about the causes of overcrowding and ambulance diversion, but little research has actually been done on this issue," says Dr. Michael Schull, assistant professor in emergency medicine at U of T and emergency department physician at Sunnybrook and Women's College Health Sciences Centre. "We felt it was important to examine the problem in a more systematic way, so we looked at the experience of Sunnybrook and Women's emergency department over a one-year period."
Schull and colleagues measured overcrowding in the emergency department by examining how often the department diverted ambulances to other hospitals in 1999. They found that, on average, the department diverted ambulances 41 per cent of the time. To identify the factors contributing to overcrowding, the researchers studied the number of ambulance and walk-in patients, the number admitted to and waiting for hospital beds, delays in the assessment of patients and their transfer to beds as well as physicians on duty and nursing staffing.
"We found the most important factors leading to overcrowding were related to those patients who were the most acutely ill and needed admission to a hospital bed," Schull says. "This suggests that if we're going to solve the problem of overcrowding then we have to increase a hospital's capacity to quickly assess, treat and admit patients who are the most acutely ill.
"We also found the number of walk-in patients, who tend to have minor illnesses, has very little impact on overcrowding in emergency. Efforts to encourage these patients to stay away from emergency departments and seek care in other places like doctor's offices probably won't do much to alleviate overcrowding, even though such cases make up about 85 per cent of emergency department visits."
Emergency departments are reasonably efficient at handling large numbers of patients with minor illness because their assessment and treatment is relatively simple and brief, Schull explains. These patients may spend a long time in the waiting room, but a full waiting room doesn't compromise an emergency department's ability to deal with a really sick patient who arrives, he says. Problems arise, however, when beds and stretchers in the emergency department are occupied by acutely ill patients who are waiting a long time for tests, decisions or a hospital bed - at this point an emergency department becomes overcrowded and very slow to accept new patients.
The researchers also conclude that nurse staffing in emergency or the rate at which physicians see and assess patients and order tests has little impact on overcrowding.
To best address the overcrowding issue, hospitals need to become more efficient in assessing and admitting the sickest patients to the appropriate wards, Schull and his co-authors say. This may mean more hospital beds, increased access to radiology tests and other resources in the off-hours or better access to home care.
"But the good news," says Schull, "is that only about 10 per cent of all emergency department patients need to be admitted, and that's who we have to focus our efforts on. The difficulty is that the solutions can't be implemented by an emergency department alone. Cooperative efforts among emergency departments, hospitals, home care and primary care services are necessary."
The full study Emergency Department Contributors to Ambulance Diversion: A Quantitative Analysis appears in the April issue of the Annals of Emergency Medicine. Schull conducted the research with Dr. Kate Lazier, Faculty of Medicine at Dalhousie University, Marian Vermeulen of health policy, management and evaluation at U of T, Dr. Shawn Mawhinney and Dr. Laurie Morrison of U of T's Emergency Medicine Division, Faculty of Medicine.
This research was supported by the Social Sciences and Humanities Research Council of Canada, the Canadian Institutes for Health Research, the Peter Lougheed Foundation and the University of Toronto.
Journal
Annals of Emergency Medicine