Do warning lights and sirens reduce ambulance response times?
OBJECTIVE
To determine the time saving associated with lights and siren (L&S) use during emergency response in an urban EMS system.


METHODS
This prospective study evaluated ambulance response times from the location at time of dispatch to the scene of an emergency in an urban area. A control group of responses using L&S was compared with an experimental group that did not use L&S. An observer was assigned to ride along with ambulance crews and record actual times for all L&S responses. At a later date, an observer and an off-duty paramedic in an identical ambulance retraced the route--at the same time of day on the same day of the week--without using L&S and recorded the travel time. Response times for the two groups were compared using paired t-test.


RESULTS
The 32 responses with L&S averaged 105.8 seconds (1 minute, 46 seconds) faster than those without (95% confidence interval: 60.2 to 151.5 seconds, p = 0.0001). The time difference ranged from 425 seconds (7 minutes, 5 seconds) faster with L&S to 210 seconds (3 minutes, 30 seconds) slower with L&S.


CONCLUSIONS
In this urban EMS system, L&S reduce ambulance response times by an average of 1 minute, 46 seconds. Although statistically significant, this time saving is likely to be clinically relevant in only a very few cases. A large-scale multicenter L&S trial may help address this issue on a national level.
Brown
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LH
Department of Emergency Medicine, State University of New York Health Science Center at Syracuse, 13210, USA. brownl@mailbox.hscsyr.edu
Whitney
C L
CL
Hunt
R C
RC
Addario
M
M
Hogue
T
T
D000552:Ambulances; D001334:Automobile Driving; D017598:Efficiency, Organizational / Q000706:statistics & numerical data*; D006801:Humans; D008029:Lighting; D009518:New York; D009622:Noise; D011446:Prospective Studies; D011482:Protective Devices / Q000706:statistics & numerical data*; D013996:Time and Motion Studies