SGEM#291: Who’s Gonna Drive you to…the ED – with Lights & Sirens?

Date: April 24th, 2020 Reference: Watanabe et al. Is Use of Warning Lights and Sirens Associated With Increased Risk of Ambulance Crashes? A Contemporary Analysis Using National EMS Information System (NEMSIS) Data. Annals of Emergency Medicine. July 2019 Guest Skeptic: Dr. Robert Edmonds is an emergency physician in the US Air Force in Virginia.  This is Bob’s eleventh visit to the SGEM. Disclaimer: The views and opinions of this podcast do not represent the United States Government or the US Air Force. Case:You are visiting with your father, a 64-year-old overweight man with hypertension.  He describes significant pain in his chest upon awakening and tells you to call an ambulance.  The EMS crew arrives and performs a 3 lead EKG that does not show an ST elevated myocardial infarction. They prepare to load your father into the ambulance, and since you’re his only child and he’s a talker, he mentions you’re an emergency physician.  The crew then asks if you want them to transport your father Code 3 with full lights and sirens. Background: The use of warning lights and sirens in ambulances is fairly widespread. Their use is associated with marginally faster response and transport times (7). Several studies have found ambulance crashes occurring while lights and sirens are used to have a higher injury rate, and a majority of fatal ambulance crashes involve their use (12-15). EMS agencies have varying guidelines on when to use lights and sirens, and the amount of time saved with lights and sirens is approximately 1-3 minutes (REF).  This means the intervention is likely unhelpful for the patient in many transports. Clinical Question: What is the association between warning lights and sirens use by EMS and crash-related delays? Reference: Watanabe et al. Is Use of Warning Lights and Sirens Associated With Increased Risk of Ambulance Crashes? A Contemporary Analysis Using National EMS Information System (NEMSIS) Data. Annals of Emergency Medicine. July 2019 Population: All dispatches of a transport-capable ground EMS vehicle to a 911 emergency scene from the 2016 National EMS Information System, both the response to the scene and the transport from the scene. Excluded: Interfacility transfers, intercepts, medical transports, and standbys; responses by nontransport or rescue vehicles, mutual aid activations, and supervisor responses; and events documented as responses or transports by rotor-wing or fixed-wing air-medical services. Intervention: Use of lights and sirens Comparison: No lights and sirens Outcome: Crash-related delay (proxy for EMS vehicle crash) Authors’ Conclusions: “Ambulance use of lights and sirens is associated with increased risk of ambulance crashes. The association is greatest during the transport phase. EMS providers should weigh these risks against any potential time savings associated with lights and sirens use.” Quality Checklist for Observational Study: Did the study address a clearly focused issue? Yes Did the authors use an appropriate method to answer their question? Yes Was the cohort recruited in an acceptable way? Yes Was the exposure accurately measured to minimize bias? Yes Was the outcome accurately measured to minimize bias? Yes/No Have the authors identified all-important confounding factors? Yes Was the follow up of subjects complete enough? Yes How precise are the results/estimate of risk? Adequate Do you believe the results? Yes Can the results be applied to the local population? Yes Do the results of this study fit with other available evidence? Yes Results: The 2016 NEMSIS database contained 20.4 million 911 dispatches of ground EMS. There was a total of 2,539 crash-related delays. Key Result: There was a greater odds ratio of crashing with the use of lights and sirens. 1) Reporting Bias: The authors mention how the study is entirely dependent on crash related...