Using Red Lights and Sirens for Emergency Ambulance Response: How Often Are Potentially Life-Saving Interventions Performed?

Prehosp Emerg Care. 2021 Jul-Aug;25(4):549-555. doi: 10.1080/10903127.2020.1797963. Epub 2020 Aug 7.


Background: Emergency Medical Services (EMS) often respond to 911 calls using red lights and sirens (RLS). RLS is associated with increased collisions and increased injuries to EMS personnel. While some patients might benefit from time savings, there is little evidence to guide targeted RLS response strategies.

Objective: To describe the frequency and nature of 911 calls that result in potentially life-saving interventions (PLSI) during the call.

Methods: Using data from ESO (Austin, Texas, USA), a national provider of EMS electronic health records, we analyzed all 911 calls in 2018. We abstracted the use of RLS, call nature, and interventions performed. A liberal definition of PLSI was developed a priori through a consensus process and included both interventions, medications, and critical hospital notifications. We calculated the proportion of calls with RLS response and with PLSI performed, both overall and stratified by call nature.

Results: There were 5,977,612 calls from 1,187 agencies included in the analysis. The majority (85.8%) of calls utilized RLS, yet few (6.9%) resulted in PLSI. When stratified by call nature, cardiac arrest calls had the highest frequency PLSI (45.0%); followed by diabetic problems (37.0%). Glucose was the most frequently given PLSI, n = 69,036. When including multiple administrations to the same patient, epinephrine was given most commonly PLSI, n = 157,282 administrations).

Conclusion: In this large national dataset, RLS responses were very common (86%) yet potentially life-saving interventions were infrequent (6.9%). These data suggest a methodology to help EMS leaders craft targeted RLS response strategies.

Keywords: emergency medical service; interventions; prehospital; red lights and sirens; safety.

MeSH terms

  • Ambulances*
  • Emergencies
  • Emergency Medical Services*
  • Emergency Service, Hospital
  • Humans
  • Texas / epidemiology