Emergency department overcrowding has become a major problem in the United States. Wait times to see a physician in emergency rooms have increased by more than 10 percent within seven years.

Because of this, there has been an increase in the phenomenon of “ambulance diversions,” where ambulances are sent ever-longer distances to hospitals with less congestion. Thirty-six percent of all U.S. hospitals experienced periods of ambulance diversions in 2007, increasing to 56 percent in urban areas.

For the paper, “The Impact of Ambulance Diversions on Heart Attack Deaths,” published in the Spring 2010 issue of Inquiry, IESE’s Natalia Yankovic teamed up with Columbia University’s Sherry Glied and Linda Green, and Morgan Grams of Johns Hopkins, to analyze how ambulance diversions affect the chances of survival for sufferers of heart attacks.

Their findings should serve as a warning for all organizations of the dangers of operating too close to capacity. At a time when companies across the board are resorting to increasingly stringent cost-cutting programs, it is worth remembering that failure to manage capacity effectively can have an enormous impact on operational flexibility and delivery.

Fatal Delays
The authors used New York City as their study location, given its geographic suitability for testing gridlock phenomena. Their findings were revealing.

• Higher levels of ambulance diversions were associated with increased heart attack deaths.
• Occurrences of gridlock – times when 25 percent or more of the borough’s hospital were on diversion at the same time – were also linked to increased heart attack deaths.
• The more diversions there were, the fewer available ambulances there were for new calls.

Clearly, if ambulance diversions can affect the rate of heart attack deaths, many other time-sensitive conditions could also be affected. Patients who have suffered strokes and life-threatening accidents could also face negative impacts from the longer time taken to travel to another hospital.

In most cities, emergency medical service protocol states that urgent cases must not be subject to ambulance diversions. In reality, this is often ignored. Even if such rules are followed, emergency department overcrowding resulting from urgent cases is likely to force more ambulance diversions further down the line.

Beware “Average Utilization” Figures
Hospital administrators need to examine their strategies when it comes to emergency department capacities and, therefore, the frequency of ambulance diversions.

In the current economic climate, hospitals, like most organizations, are facing increasing pressure to downsize or close. According to the authors, however, the current problems in capacity management have their roots in decisions made long before the onset of a crisis.

During 2004, the average hospital occupancy in New York City ranged from 73 percent to 86 percent, leading a state commission to conclude there was excess capacity and the service could be reduced.

However, they failed to take into account that the peak capacity averaged 98 percent across the city – with as much as 106 percent in Manhattan – during the same period.

And as emergency department congestion has increased, delays have also increased. Average wait times for treatment among heart attack sufferers rose from 8 minutes to 20 minutes between 1997 and 2004.

Seasonal Variations
Temporal variations need to be taken into account too, with particular periods of the year, week and day all having different congestion levels. The study found that 44 percent of all diversions were between 12 a.m. and 8 a.m., for instance.

Care needs to be taken in assessing emergency department capacities, as well as the untold impact that management decisions will have on ambulance diversion rates.

Building an infrastructure that provides the needed flexibility and speed of delivery during times of high demand requires an in-depth understanding of the impact of capacity on an organization.

In a time of financial uncertainty, the temptation can be to cut services when they appear to be underused. But care must be taken to ensure the real cost is not people’s lives.