How fast should ambulances go?
Posted Tuesday, May 11, 2010, at 1:07 PM
We have all pulled aside on the road to let a speeding, blaring ambulance whiz by, assured by the collective wisdom that every second matters for the unlucky patient inside. But, in truth, there are tragic but opposing stories about the importance of speed during a medical emergency.
Take the case of Ashley Leveillee, a seemingly healthy baby girl. On a summer day in 1996, just outside of Boston, Ashley had a seizure and turned blue in front of her horrified parents. It took 22 minutes for the ambulance to arrive. The medics, who took a circuitous route to the home, were observed (by police, who had arrived first) taking their time walking up the driveway. Then the ambulance crew struggled to get the baby anti-seizure medication she needed quickly. Ashley ended up paralyzed for life. Her parents received a $10 million settlement, in part because the medics "took too long." The death of Princess Diana in 1997 is more famous example of too-slow emergency care. According to reports, Diana's ambulance ride to the hospital should have been five to 10 minutes but took 40 minutes because, applying standard French emergency procedures, they drove extremely slowly so as "not to subject the fragile patient to shocks and bumps." American heart surgeon John Oschner opined that Diana may have been saved had she arrived at the hospital sooner.
The competing story is about a woman who had only an injured finger when she died after her ambulance ran "hot"—lights and sirens blaring—through an intersection and crashed into another vehicle. And just recently in New York, two separate fatal ambulance crashes occurred while its medics were speeding to deliver care. The "Ambulance Crash Log" details many accidents in which rescue vehicles require some rescuing.
Nothing represents the urgency of time in emergency care better than the blazing ambulance, its lights and sirens clearing its path. Some of the supposed importance of speed in medical emergencies is actually grounded in truth: For patients with cardiac arrest, the time it takes for someone to start CPR makes a big difference in survival. But for many other conditions, time (on the order of minutes) may not make as much of a difference as we once thought.
Take the "golden hour," a concept of emergency care that is so deeply held and widely disseminated that they named a British TV show after it. The theory of the golden hour proposes that patients with serious trauma who get to the hospital within 60 minutes of injury are far more likely to survive. On its face, this rule makes sense: If you are bleeding internally, a surgeon can stop the hemorrhage as long as she can get to the source of the bleeding quickly enough. While the golden hour has become dogma, it turns out not to be backed by good science.
Now a recent study in the Annals of Emergency Medicine casts further doubt to the concept of the golden hour for patients with severe injury. The authors studied more than 3,000 trauma patients—those with low blood pressures from bleeding, head injuries, and difficulty breathing—and looked at various time intervals after a 9-1-1 call. The times were compared with outcomes for the patients in the hospital. The result: shorter intervals did not appear to improve survival. These results are fascinating, in part because the principal question—how important is speed in the care of trauma patients before they get to the hospital?—has never been so elegantly explored. Previous efforts to measure the effect of ambulance time on survival have been plagued by the fundamental problem that medics may behave differently, like driving faster or spending more time working on patients, depending on the severity of the condition, making it impossible to tease out the effect of time on survival. While some of these biases remain, the authors of this study used sophisticated methods to account for many of these problems, allowing the reader to reasonably conclude that for ambulance care, a few minutes either way neither saves nor costs lives for patients with severe trauma.
What are the consequences of this new information? It may encourage some changes in the way ambulances behave on the roads. The editors of the journal that published the study proclaim, "Routine lights-and-sirens transport for trauma patients … may not be warranted." This conclusion is driven, in part, by increased awareness of the dangers of speeding ambulances. Ambulance crashes occur relatively frequently, killing medics at a rate that is nearly three times higher than that of the average U.S. worker. In some places, three in four ambulance crashes occur while the vehicles are running hot, even though lights and sirens don't save much time at all. More alarming are how bad the injuries are for people who aren't even in the ambulance, such as when drivers swerve out of their path to cause another crash or strike an unlucky pedestrian.
But it would be wrong, and irresponsible, to claim that time doesn't make a difference in the delivery of emergency care. Some medical conditions are truly time-sensitive, such as episodes of choking, in which performing the Heimlich maneuver can be life-saving, and cardiac arrest, in which medics can shock and restart their heart. But as new and better evidence suggests that very small differences in time my not be as important as other factors in the delivery of care for seriously ill patients, we should be clear about policies that may save minutes but not lives. This is important, because many ambulance services are benchmarked for quality on response time, which in turn may encourage ambulances to continue to speed.
Perhaps it's time to tell ambulance drivers to slow down and quiet down. Leadership organizations in prehospital care are on it: Reports such as this from the National Association of EMS Physicians speak to a need to negotiate the conflict for ambulances to get there quickly and get there safely. While we don't want more stories like Ashley's, we also don't want ambulance drivers putting themselves, their patients, and other citizens at risk, especially when minutes don't count as much as we once thought.
Zachary F. Meisel is a practicing emergency physician, a Robert Wood Johnson Foundation clinical scholar at the University of Pennsylvania, and a senior fellow at the Leonard Davis Institute of Health Economics.
Jesse M. Pines is a practicing emergency physician and an associate professor of emergency medicine and health policy at George Washington University in the Center for Health Care Quality.
Photograph of ambulance by Thinkstock/Getty Images.