Lights and Sirens

We all know the rush of flipping on the lights and sirens. It feels like we’re flying, but have you ever wondered if that "fast" ride is actually a dangerous gamble?

In this episode of From Science to the Scene, the National Registry Research Team dives into a massive study of over 19 million EMS calls. Host Chris Gage breaks down the math on whether "driving hot" actually helps or just hurts.

The Shocking Stats:
- The Time Myth: On average, lights and sirens only save about 1 to 3 minutes.
- The Danger Zone: Using them during a response makes a crash 50% more likely.
- The Transport Trap: When you have a patient in the back and use lights and sirens to the hospital, your risk of a crash nearly triples.

Is saving two minutes worth a 300% increase in crash risk? Tune in to hear why the data is forcing us to rethink the way we drive.

Check out the full study here: https://www.annemergmed.com/article/S0196-0644(18)31325-8/abstract

Transcript

SPEAKER_00 0:18

Hey everyone, my name is Chris Gage, and today we're going to dig into a critical question in EMS operations. Does lights and sirens actually increase the risk of ambulance crashes? It's a question that every EMS clinician, supervisor, and policymaker should care about. And one that this study, published by Annals of Emergency Medicine, answers using national data from Nensus database. So lights and sirens are standard feature that we all know about used in emergent response. They're meant to clear the path and reduce time to patients or hospitals. But there's one little thing. Previous research has shown that only they save only about a minute to three minutes on average. I mean, that's not nothing, but it's actually not that much either, especially when you start to consider the risks that involved. We've known that lights and sirenes may be tied to more injuries and even more fatal crashes, but we haven't had a large national statistically rigorous study looking directly at whether they cause more crashes until the Wantabe and team released this manuscript in 2019. This study set out to answer one core question: are ambulance crashes more likely when lights and sirens are used? So the researchers took a pretty conservative approach. Their starting hypothesis was that there was no difference in ambulance crashes based on lights and sirings use. The data would either confirm or reject that. So to do this, they used the 2016 Nempsys dataset, which included over 19 million EMS activations from nearly 10,000 agencies across the United States. They were given mask agency data to adjust for agency characteristics. So they focused only on ground 911 scene responses with transports. Importantly, here, they analyzed two phases separately, the response to the scene and the transport from the scene to the hospital. So they used reported delays due to ambulance crashes as a proxy for the actual crash itself and ran multivariable logistic regression to calculate adjusted odds ratios. So these models controlled for agency characteristics, urbanicity, time of day, and other operational factors. So what did they find? Okay, well let's start with the response phase. So getting to the scene. So the crash rate when lights and sirens were not used was about 4.6 crashes per 100,000 responses. But with lights and sirens, it only rose slightly to 5.4 crashes per 100,000 responses. Now that is an adjusted odds ratio of about one and a half, meaning a 50% increase in crash odds. But honestly, in absolute terms, it's less than one crash per 100,000 responses. So yes, there is an increased risk, but really just slightly, and not necessarily in a way that's operationally alarming. Now let's talk about the transport phase, right? So getting the patient from the scene to the hospital. So here the numbers tell a little bit of a different story. Without lights and sirens, the crash rate was about seven per 100,000 responses or transports. But with lights and sirens, it jumped to 17.1 per 100,000 transports. Now that is adjusted odds ratio of 2.9, nearly triple the odds of a crash. So in absolute terms, yes, that does make a difference. That's over 10 extra crashes per 100,000 transports. So that's roughly one additional crash per 10,000 patient transports. And honestly, that's pretty meaningful increase in this risk. Could this just be a fluke? I mean, the researchers wanted to be sure, right? You want to make sure everything's right. So they ran multiple stratified and sensitivity analysis to test the consistency of their findings. They looked at small versus large agencies, urban versus rural, different staffing models, right? Different levels of lights and siren use, and across the board, especially during the transport phase, the increased risk of crash and lights and sirings use persisted throughout. Even when they excluded some extreme cases or assumed missing data represented no lights and siren use, the results remain the same. Of course, every study has its limitations, and this one is no exception. The biggest is that they use crash-related delays as a proxy for ambulance crashes. That means some minor crashes may have been missed if they didn't delay care. Also, they couldn't really assess crash, severity, or injuries and couldn't account for other variables like weather, road conditions, or patient acuity. But the data set's huge and consistent, and the model was conservative. So despite some of these limitations, the findings are still highly credible. So what does this mean for EMS systems and clinicians? The takeaway is pretty clear. We need to use lights and sirings more judiciously, especially during the transport phase. And not every call, certainly not every transport, needs to be done with lights and sirings blaring. So this study supports what many EMS leaders and clinicians have already been pushing for: more discretion, better protocols, and greater attention to safety. It's about, you know, striking the right balance between speed and risk. So let's wrap this up. Lights and sirings can save a few minutes that might be critical for some patients. But those minutes might come at the cost of crashes, injuries, and even deaths. And the risk is greatest during transport when the driver's alone, adrenaline is high, and distractions are everywhere. This study offers the strongest national evidence yet that it's time for EMS systems to reevaluate lights and siren policies. It's not about eliminating them, just being smarter about their use. So the next time your fingers hover over those little swishes, ask yourself, is lights and sirens worth the risk with this patient? So thanks for joining us today. Until next time, whether you're hitting the books or hitting the streets, stay safe, stay curious, and keep bringing science to the scene. Thanks.