Emergency medical dispatchers’ ability to identify large vessel occlusion stroke during emergency calls

Abstract

Background In acute ischemic stroke, conjugated eye deviation (CED) is an evident sign of cortical ischemia and large vessel occlusion (LVO). We aimed to determine if an emergency dispatcher can recognise LVO stroke during an emergency call by asking the caller a binary question regarding whether the patient’s head or gaze is away from the side of the hemiparesis or not. Further, we investigated if the paramedics can confirm this sign at the scene. In the group of positive CED answers to the emergency dispatcher, we investigated what diagnoses these patients received at the emergency department (ED). Among all patients brought to ED and subsequently treated with mechanical thrombectomy (MT) we tracked the proportion of patients with a positive CED answer during the emergency call. Methods We collected data on all stroke dispatches in the city of Tampere, Finland, from 13 February 2019 to 31 October 2020. We then reviewed all patient records from cases where the dispatcher had marked ‘yes’ to the question regarding patient CED in the computer-aided emergency response system. We also viewed all emergency department admissions to see how many patients in total were treated with MT during the period studied. Results Out of 1913 dispatches, we found 81 cases (4%) in which the caller had verified CED during the emergency call. Twenty-four of these patients were diagnosed with acute ischemic stroke. Paramedics confirmed CED in only 9 (11%) of these 81 patients. Two patients with positive CED answers during the emergency call and 19 other patients brought to the emergency department were treated with MT. Conclusion A small minority of stroke dispatches include a positive answer to the CED question but paramedics rarely confirm the emergency medical dispatcher’s suspicion of CED as a sign of LVO. Few patients in need of MT can be found this way. Stroke dispatch protocol with a CED question needs intensive implementation.

Cortical symptoms described in emergency calls for patients with suspected large vessel occlusion: a descriptive analysis of 157 emergency calls

“…In the calls we studied, the CED question was either not asked or was asked but in a way that failed to elucidate the direction of the possible forced gaze. In our previous study [ 20 ] we did not have access to the emergency call recordings. We concluded in that study that the ERICA reports show that in 17% of suspected stroke dispatches the CED question is unanswered.…”

“…Our second aim of this study was to find out why the CED question did not recognize LVO patients in our previous study [ 20 ]. Therefore, we deliberately chose to listen to emergency calls in which we could easily demonstrate that the paramedics had recognized the patient as a thrombectomy candidate on the grounds of CED.…”

“…This could drastically change the EMS strategy by making it possible to activate a mobile stroke unit [ 18 ] or a helicopter [ 19 ] early in the triage and transport an LVO stroke patient directly to the comprehensive stroke centre (CSC). Unfortunately, in our previous publication [ 20 ], we concluded that the answer the dispatchers marked in the dispatch database to the CED question: ‘is the face or the gaze of the patient away from the side of the hemiparesis?’ did not recognize patients with LVO.…”

Differences between the dispatch priority assessments of emergency medical dispatchers and emergency medical services: a prospective register-based study in Finland

“…Quick response from the emergency medical dispatcher (EMD) may reduce the first EMS unit's time to reach the patient [8], but a problem may arise if the EMS units are dispatched urgently to a non-urgent incident and thus, are unable to respond immediately to other critical missions [9]. In truly time-critical situations such as cardiac arrests or strokes, rapid and correct dispatch is crucial [10][11][12][13]. This creates a situation where a certain amount of over-triage is necessary and acceptable to ensure that the patients receive immediate and proper response when needed.…”

“…However, high rates of over-triage can be harmful for the EMS in numerous ways, leading to excessive costs, inappropriate use of resources [14], increased risk of ambulance crashes [15] and overfatigue of the EMS personnel [16]. To improve the quality of emergency dispatch, a new computer-assisted emergency dispatch system called Emergency Response Integrated Common Authorities (ERICA) was introduced in Finland in 2018 [12].…”