EMS Myth #4: Lights and sirens save a significant amount of travel time and lives

As a kid growing up in Fort Worth, TX, I remember the funeral home ambulances of the era. In fact, in the late 1950s, my father sold ambulances and hearses for a company named Hess and Eisenhart. Ambulances at that time had little in the way of medical equipment. In terms of patient care, they offered little more than oxygen and rapid horizontal transport. The ambulances of that period were designed for speed. They had high-performance engines, numerous flashing lights and large, loud mechanical sirens. When you heard one coming, if you looked out the window quickly enough you could see a flash and a blur as it sped by. They were neat.
      In the 1960s, the city of Fort Worth had an unusual custom. They used to paint a large white "X" on the street where there had been a traffic fatality. I remember an intersection on Camp Bowie Boulevard where there were two "X" marks. These were the result of two ambulances colliding at tremendous speed at the intersection en route to a 10–50 major (major accident) somewhere west of town. Today, the two "X" marks on Camp Bowie Boulevard are gone, but every time I drive by that intersection, I remember the story of the two ambulance drivers who died there.

History
      Despite being significantly more medically sophisticated, many EMS services still routinely respond to all emergency calls, regardless of the nature, with emergency lights and sirens. Some routinely transport patients to the hospital using emergency lights and sirens, using the argument that they are able to get the unit back in service quickly. Many times, even in large EMS systems, I have seen an ambulance asked to increase to Code 3, not because of patient condition, but just because the system was busy. This practice contradicts one of our EMS prime directives: Patient care comes first.
      Does the use of lights and sirens in emergency response and transport save a great deal of time? Should patient condition and nothing else guide usage of emergency lights and sirens? Do the benefits of lights and sirens transport outweigh the possible risks?

The Scientific Evidence
      Unlike many of the topics we have addressed in this series on EMS myths, the scientific literature related to use of emergency lights and sirens is quite limited—and what literature exists does not clarify the issue. First, do lights and sirens save a significant amount of time? Researchers in North Carolina compared lights and siren transport to non-lights and siren transport in an urban setting where transport time to a university medical center involved distances of eight miles or less. They found that lights and siren transport only averaged 43.5 seconds faster than non-lights and siren transport. They concluded, "Although the mean difference is statistically significant, it is not clinically significant, except in rare circumstances." ¹ A similar study conducted in Syracuse, NY, found that lights and siren response reduced response times by an average of 1 minute, 46 seconds. They concluded, "Although statistically significant, this time saving is likely to be clinically relevant in only a few cases." ² Researchers in Minneapolis, MN, similarly studied the role of emergency lights and sirens in emergency response times. They studied 64 runs over a nine-month period and concluded that responses with lights and sirens saved an average of 3.02 minutes over non-lights and siren responses.³ Additional studies are needed to clarify this issue. But, geographical differences, distances to hospitals and other variables may never allow this question to be adequately studied.
      So, should patient condition, and nothing else, guide usage of emergency lights and sirens? This may be a little clearer. Pennsylvania researchers studied a county-wide, single-provider, private EMS system that used 11 ALS ambulances. Annual call volume for the service area was 14,000, and the county population was approximately 90,000. A medical protocol was developed, and carried on each ambulance, that provided medical criteria for lights and siren transport. A total of 1,625 patients were entered into the study. Based on the medical protocol, 92% of patients were transported without lights and sirens, while 8% were transported with lights and sirens. No adverse outcomes were identified as being related to non-lights and siren transport.⁴
      How much time makes a difference? This remains unclear. Much EMS practice is based upon the concept of a so-called "Golden Hour." However, recent studies have shown that there is little evidence to either support or refute the concept of a "Golden Hour."^5,6 Intuitively, some emergencies may benefit from rapid response and transport; however, most probably will not. With this in mind, we must weigh the benefits of lights and siren response (which appear fairly minimal) with the potential risks (which appear to be fairly significant).
      Do the benefits of lights and siren transport outweigh the possible risks? Again, this must be a local decision. A recent study estimated that the fatality rate for EMS personnel is 12.7 fatalities per 100,000 EMS workers annually, which compares with 14.2 for police, 16.5 for firefighters, and a national average of 5.0 during the same time period. Most fatalities were due to traffic accidents.⁷ Some industry experts have estimated that there are 12,000 ambulance-related crashes annually in the United States, causing nearly 120 deaths.⁸ Numerous accidents have been attributed to use of emergency lights and sirens.⁹ But, there are several factors to consider. Many EMS and fire services poorly prepare their personnel for emergency vehicle operation, especially when compared to training of law enforcement officers. Second, in many areas, EMS provider knowledge of basic traffic safety laws pertaining to emergency vehicle operation is poor.^10,11 We need to address these issues to assure that lights and siren response is as safe as possible and used as little as possible.

Conclusion
      Based on the available scientific literature, the issue of widespread use of emergency lights and sirens boils down to a simple risk versus benefit equation. It is clear that the use of emergency lights and sirens constitutes a clear and present danger for both emergency personnel and the general public. It is true that, in most cases, time can be saved with lights and siren response. However, this rapid response may only benefit a very small number of patients. To quote the great philosopher Mr. Spock, "The needs of the many outweigh the needs of the few." A patient's medical condition, and nothing else, should determine whether lights and sirens should be used. For the response phase, dispatchers should utilize medical protocols to determine which patients should receive a lights and siren response. Likewise, EMS field providers should use a similar medical protocol to determine which patients will potentially benefit from emergency lights and siren transport. It is as simple as that. We've seen enough white "X" marks on the roadways.

References
1. Hunt RC, Brown LH, Cabinum ES, et al. Is ambulance transport time with lights and siren faster than that without? Ann Emerg Med 25(4):507–511, 1995.
2. Brown LH, Whitney CL, Hunt RC, et al. Do warning lights and sirens reduce ambulance response times? Prehosp Emerg Care 4(1):70–74, 2000.
3. Ho J, Casey B. Time saved with use of emergency warning lights and sirens during response to requests for emergency medical aid in an urban environment. Ann Emerg Med 32(5):585–588, 1998.
4. Kupas DF, Dula DJ, Pino BJ. Patient outcome using medical protocol to limit "lights and siren" transport. Prehosp Disast Med 9(4): 1994.
5. Bledsoe BE. The golden hour: fact or fiction. Emerg Med Serv 31(6):105, 2002.
6. Lerner LB, Moscati RM. The golden hour: scientific fact or medical "urban legend"? Acad Emerg Med 8(7):758–760, 2001.
7. Maguire BJ, Hunting KL, Smith GS, Levick NR. Occupational fatalities in emergency medical services: A hidden crisis. Ann Emerg Med 40(6):625–632, Dec. 2002.
8. Charalambous N. Sirens to be limited to emergencies. Anderson Independent-Mail (November 21, 2002).
9. Wolfberg D. Lights, Sirens and Liability. J Emerg Med Svcs 21(2):38–40, 1996.
10. Whiting JD, Dunn K, March JA, et al. EMT knowledge of ambulance traffic laws. Prehosp Emerg Care 2(2):136–140, 1998.
11. Chapleau W. Lights & sirens. Emerg Med Serv 31(6):59, 2002.

Bryan Bledsoe, DO, FACEP, EMT-P, is an emergency physician, author and former paramedic whose writings include: Paramedic Care: Principles and Practice and Paramedic Emergency Care.