Identifying Key Words in 9-1-1 Calls for Stroke: A Mixed Methods Approach

Abstract

Objectives Identifying stroke during a 9–1-1 call is critical to timely prehospital care. However, emergency medical dispatchers (EMDs) recognize stroke in less than half of 9–1-1 calls, potentially due to the words used by callers to communicate stroke signs and symptoms. We hypothesized that callers do not typically use words and phrases considered to be classical descriptors of stroke, such as focal neurologic deficits, but that a mixed-methods approach can identify words and phrases commonly used by 9–1-1 callers to describe acute stroke victims. Methods We performed a mixed-methods, retrospective study of 9–1-1 call audio recordings for adult patients with confirmed stroke who were transported by ambulance in a large urban city. Content analysis, a qualitative methodology, and computational linguistics, a quantitative methodology, were used to identify key words and phrases used by 9–1-1 callers to describe acute stroke victims. Because a caller’s level of emotional distress contributes to the communication during a 9–1-1 call, the Emotional Content and Cooperation Score was scored by a multidisciplinary team. Results A total of 110 9–1-1 calls, received between June and September 2013, were analyzed. EMDs recognized stroke in 48% of calls, and the emotional state of most callers (95%) was calm. In 77% of calls in which EMDs recognized stroke, callers specifically used the word “stroke”; however, the word “stroke” was used in only 38% of calls. Vague, non-specific words and phrases were used to describe stroke victims’ symptoms in 55% of calls, and 45% of callers used distractor words and phrases suggestive of non-stroke emergencies. Focal neurologic symptoms were described in 39% of calls. Computational linguistics identified 9 key words that were more commonly used in calls where the EMD identified stroke. These words were concordant with terms identified through qualitative content analysis. Conclusions Most 9–1-1 callers used vague, non-specific, or distractor words and phrases and infrequently provide classic stroke descriptions during 9–1-1 calls for stroke. Both qualitative and quantitative methodologies identified similar key words and phrases associated with accurate EMD stroke recognition. This study suggests that tools incorporating commonly used words and phrases could potentially improve EMD stroke recognition.

Stroke mimics: incidence, aetiology, clinical features and treatment

“…Emergency medical dispatch services (MDS) is very often the first point of contact for patients with suspected stroke or their attendant and plays an important role in the optimization of delivery of care. Frequently the caller uses vague, non-specific or potentially distractor words making it difficult for the dispatcher to recognize the diagnosis [ 22 ]. The dispatchers are very exposed to a wide variety of incoming calls and have a difficult task to rapidly identify stroke symptoms and prioritize ambulance dispatch.…”

Symptoms presented during emergency telephone calls for patients with spontaneous subarachnoid haemorrhage

“…In ischaemic stroke, improved recognition by EMDs has resulted in a shorter ambulance response times, shorter on-scene times, earlier arrival to stroke centers, and faster inhospital responses through pre-arrival notifications. The EMDs are crucial in this process, as any information obtained may be forwarded to the EMS to assist them in choosing the appropriate hospital [ 20 – 23 ]. This is also very likely to be the case with SAH.…”

Utstein recommendation for emergency stroke care

“…Some identification strategies are insensitive, detecting between 40 % and 65 % of acute strokes with variable specificity. 25 – 27 There is no evidence favoring any one particular diagnostic scale or strategy by emergency call takers to identify stroke. 28 However, using a tool to facilitate rapid recognition seems obvious and recently the American Heart Association/American Stroke Association has recommended new time process indicators for emergency call-taking and dispatch.…”