An Evaluation of Emergency Medical Services Stroke Protocols and Scene Times

Abstract

Background Acute stroke patients require immediate medical attention. Therefore, American Stroke Association guidelines recommend that for suspected stroke cases, emergency medical services (EMS) personnel spend less than 15 minutes (min) on-scene at least 90% of the time. However, not all EMS providers include specific scene time limits in their stroke patient care protocols. Objective We sought to determine whether having a protocol with a specific scene time limit was associated with less time EMS spent on scene. Methods Stroke protocols from the 100 EMS systems in North Carolina (NC) were collected and abstracted for scene time instructions. Suspected stroke events occurring in 2009 were analyzed using data from the NC Prehospital Medical Information System. Scene time was defined as the time from EMS arrival at the scene to departure with the patient. Quantile regression was used to estimate how the 90th percentile of the scene time distribution varied by systems with protocol instructions limiting scene time, adjusting for system patient volume and metropolitan status. Results In 2009, 23 EMS systems in NC had no instructions regarding scene time; 73 had general instructions to minimize scene time; and 4 had a specific limit for scene time (i.e. 10 or 15 min). Among 9,723 eligible suspected stroke events, mean scene time was 15.9 min (standard deviation 6.9 min) and median scene time was 15.0 min (90th percentile 24.3 min). In adjusted quantile regression models, the estimated reduction in the 90th percentile scene time, comparing protocols with a specific time limit to no instructions, was 2.2 min (95% confidence interval 1.3, 3.1 min). The difference in 90th percentile scene time between general and absent instructions was not statistically different (0.7 min (95% confidence interval -0.1, 1.4 min)). Conclusion Protocols with specific scene time limits were associated with EMS crews spending less time at the scene while general instructions were not. These findings suggest EMS systems can modestly improve scene times for stroke by specifying a time limit in their protocols.

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)

“…The projected direct-to-endovascular-capable hospital (bypass) time was calculated based on the actual driving distance from the scene directly to the endovascular-capable center combined with the actual average ambulance velocity observed during the interfacility transport and a projected average emergency medical services time on scene of 15 minutes. 15 – 17 For patients with IV-tPA, the average (mean) door–to–tissue-type plasminogen activator (tPA) time at endovascular-capable sites was then added to predict onset-to-tPA time. Any patients whose predicted bypass onset-to-tPA time exceeded guideline recommendations 15 were identified as no longer tPA-eligible.…”

Acute Stroke: Current Evidence-based Recommendations for Prehospital Care

“…That led to reductions in on-scene time over those with no instructions and those with general instructions to limit on scene time. 97 …”

Pre and intrahospital workflow for acute stroke treatment

“…In a 2009 analysis of 86 EMS systems in North Carolina, a protocol specific scene time limit of 15 min reduced scene times by 2.2 min in those systems with specified scene times compared with those without; overall mean scene time was 15.9 min [15]. The authors concluded that EMS systems can modestly reduce on-scene times with specified limits on scene time.…”