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Nothing Gold Can Stay?

2010; Elsevier BV; Volume: 56; Issue: 5 Linguagem: Inglês

10.1016/j.annemergmed.2010.09.012

1097-6760

Ėric Berger,

Emergency and Acute Care Studies

On a steamy Harlem morning last July, an Acura blasted its radio while approaching the intersection of 125th Street and Seventh Avenue. As a result, the car's driver did not hear the sirens of an oncoming ambulance and broadsided the emergency vehicle, which was responding to a call in haste. Reacting to the Acura, the ambulance swerved and crashed into a city bus and Ford Expedition. Nineteen people were injured, requiring the services of several more ambulances. A week later I telephoned Nadine Levick, MD, MPH, who told me she lives about 10 blocks from the intersection where the crash occurred. An emergency physician who researches emergency medical services (EMS) transport, Dr. Levick has become a leading crusader for increasing information about the prevalence of ambulance crashes, increased oversight of EMS and slowing down ambulances on most emergency calls. “The accident certainly highlights the issue,” she said. Dr. Levick's cause—a reevaluation of speed at all costs in delivering patients to the hospital—has gained ground in recent years as scientists have stepped up their investigations into the notion of a “golden hour,” the time-honored idea that patients have the best chance of surviving a traumatic injury if they receive medical care within 60 minutes. In several studies, scientists have accumulated a growing amount of evidence that time does not always matter when it comes to traumatic injuries. The golden hour, it seems, stands on a foundation of less than rigorous scientific evidence. The concept is most widely credited to famed trauma surgeon R. Adams Cowley, a pioneer in emergency medicine who spearheaded the creation of the nation's first statewide EMS system in Maryland. Cowley originated the idea on a cocktail napkin in a Baltimore bar, said Bryan Bledsoe, DO, a professor of emergency medicine at the University of Nevada School of Medicine. A review of Cowley's writings, published in the July 2001 issue of Academic Emergency Medicine, found no scientific articles backing up his assertion about the significance of a single hour in the mortality of a patient. “I write a widely used paramedic textbook,” said Dr. Bledsoe. “In the latest edition, we changed the golden hour description to golden period to take the concept of an hour out. The bottom line is that we just don't know. Is 30 minutes better? Is 90 minutes OK? I think it seemed like a good idea at the time, and because it was intuitive it was embraced. But now we need to take a good, hard, scientific look at the concept.” One of Cowley's disciples, Robert R. Bass, MD, has heard the criticisms of the golden hour and accepts the need to revisit the issue with scientific rigor. But as executive director of the Maryland Institute for Emergency Medical Services, overseeing and coordinating all components of the statewide EMS system, he rejects the idea that the golden hour is a flawed concept. “You've got to look at it from Cowley's perspective,” Dr. Bass said. “He was running this little trauma lab, and the vast majority of patients he got were dying because they weren't getting proper support in the field. He just wasn't getting them in time. So he coined the term ‘the golden hour' to teach the public and government the importance of getting these patients to the trauma center in a timely manner. In that sense, it's been magical. I don't believe Cowley ever intended to apply that statement to every single trauma patient. It was a very important sound bite that taught a very important message in the 1960s and 1970s that really needed to be addressed.” During the era when Cowley formulated his ideas, patients were dying frequently from traumatic injuries, Dr. Bass said, because there was no organized system of care. During the succeeding 4 decades, the nation has rapidly developed a system of trauma care. Cowley's basic principles remain valid, Dr. Bass said, because patients with serious illnesses need to be cared for in a timely way and then taken to an appropriate facility. Nevertheless, scientists have begun to seriously reappraise the golden hour. One of the most significant studies, published in the March 2010 issue of this journal, found no association between EMS intervals and improved survival among injured patients. “We weren't able to identify an association between EMS time and mortality,” said the study's lead author, Craig Newgard, MD, MPH, a professor of emergency medicine at the Oregon Health & Science University. “The study needs to be placed in context of its limitations so it is used appropriately. There's a danger of using a study like this to say time doesn't matter, or that EMS does not need to move quickly. We're not trying to say that. This study probably doesn't tell the full story, and there are pieces of the story that are still out there.” Researchers generally agree there's not a definitive study on whether a “golden hour” exists. When considering the time to treatment in a hospital, there are generally 3 phases. The first lasts from the point when a patient is injured to the time when 911 is notified. The second phase lasts from the time of 911 notification to delivery of a patient to the hospital. The third period is the interval between arrival at the hospital and actual medical intervention in the emergency center. Dr. Newgard's study assessed the middle phase, the EMS interval, by analyzing a database of 3,656 trauma patients transported by 146 EMS agencies to 51 Level I and II trauma hospitals in 10 North American sites from 2005 to 2007. He observed several limitations to the study, such as the potential for a strong time bias that's difficult to correct for. With sicker, more seriously injured patients, EMS providers tend to work more quickly, whereas the provider may feel he or she has more time with lower-acuity patients. This may bias the findings by associating longer times with better outcomes. “We just didn't have enough variables to fully account for this bias and to try and tease out what the real association is behind time and survival,” Dr. Newgard said. Nevertheless, Dr. Newgard's study, and others like it, has helped fuel a discussion in the emergency medicine community about the primacy of speed when it comes to trauma patients. “My belief is that this article is a game changer,” said Zachary Meisel, MD, MPH, a Robert Wood Johnson Foundation clinical scholar at the University of Pennsylvania Department of Emergency Medicine. “I think he looked at the sickest trauma patients for whom you would reasonably say time is likely to make the most difference and was able to show that it consistently did not. Whether this means we have to rejigger our whole trauma system, maybe not. We're talking about differences of minutes here. But it does beg the question about some of the bigger-picture questions of helicopter versus ground versus bypassing local hospitals for trauma centers. There's a planting of the seed here that there may be less downside to bypassing hospitals than we used to think.” A former EMS medical director in western Pennsylvania, Dr. Meisel said studies that challenge the concept that time matters touch “hot button issues” and that there will inevitably be counterexamples, such as a choking baby, when a provider reaching the scene immediately can be a lifesaver. Yet there's clearly evidence that in the aggregate many trauma patients need not be rushed to the hospital. “This challenges the idea of lights and sirens,” Dr. Meisel said. “The big question I take away from this is, what are the unintended consequences of lights and sirens and speeding? The data for this is woefully undermeasured, and we just don't have good answers. This is an area where more evidence needs to come.” No one is more aware of this than Dr. Levick, who chairs the EMS Transport Safety Subcommittee of the National Academies Transportation Research Board. Although there is a paucity of data, there are some statistics Dr. Levick says she can substantiate about the safety of ambulance transport. Of patients transported in ambulances, she said, 97% do not have life-threatening injuries. (How many of these patients were transported with lights and sirens is unknown). Additionally, in urban settings, using lights and sirens saves an average of 2 minutes in transport time to a hospital. What is unknown about ambulance transport is how many crashes actually occur and how many injuries and fatalities they cause. Instead, there are estimates of US EMS transport safety: 50,000 vehicles on the road, 9,000 crashes a year, 1 fatality a week (two thirds of which are occupants of other vehicles), 10 serious injuries each day, and an annual cost of $500 million. Dr. Levick said ambulances are the most lethal vehicle on the road both per mile traveled and per vehicle. They are exempt from federal commercial fleet safety oversight and exempt from most federal motor vehicle safety standards. Intuitively, she said, it may make sense that EMS providers would want to drive as quickly as possible to the hospital. “But when you actually look at it scientifically, the emperor has no clothes,” she said. Another consideration, Dr. Levick said, is that in an ambulance traveling quickly the same level of care cannot be given to a patient. She cited a study (doi:10.1016/j.resuscitation.2010.02.024) by Korean researchers in the journal Resuscitation that found the more quickly a vehicle moved, the worse a patient undergoing cardiopulmonary resuscitation fared. “When you start to think about the actual mechanics and real issues involved, the intuitive response of speeding goes away,” she said. “In very rare circumstances, speed may be helpful, but for the most part it's probably better to have a slow gentle ride.” Researchers agree that the solutions to these issues require a rigorous scientific approach. First, more work must be done to tease out the validity of the golden hour. What patients—outside of obvious cases such as cardiac arrest—benefit most from timely intervention? What patients are less time dependent and need not be rushed to the hospital? “Anyone who has been an EMS provider knows that it is very difficult to assess patients in the field, to identify quickly which ones have serious injuries,” Dr. Bass said. “Sometimes it's obvious: a patient has trouble breathing or altered mental status. But then there are other patients who have occult injuries who will physiologically decline over time. All patients have some sort of slope of decline. How do you select out those patients who need care in a rapid fashion? The challenge we have today is sorting those patients.” State transport data systems also need to be altered to capture data on the safety of EMS transport. As this information comes forward, it will become possible to devise policies for when lights and sirens should be used and, likely more commonly in future years in urban settings, when they should not be used. “I think that's already been happening,” Dr. Bass said. “My gut feeling after talking to my colleagues around the country is that we're seeing less use of lights and sirens than we did 5 or 10 years ago.” A final piece of the puzzle may be public awareness. Many urban EMS systems in the United States have a response time standard of 8 minutes or less, and these artificial standards are often codified in the municipal laws. The concept of the golden hour has become so widely adopted that consumers, and their elected legislators, expect it. “What needs to happen is a large organized study, perhaps by the Institute of Medicine, that lets the public know that adhering to the golden hour has costs and isn't always necessary,” said Dr. Bledsoe, the Texas emergency physician who has long been a critic of the golden hour. “Until you do something like that, you're really swimming upstream. After decades of this, consumers have expectations. All that needs to happen in this 24-hour news cycle is to have one child die because of lax response times, and we're back to square 1.”