Prehospital identification and priority of acute stroke

University dissertation from Stockholm : Karolinska Institutet, Dept of Clinical Science and Education, Södersjukhuset

Abstract: Treatment of acute ischemic stroke is time critical and early initiated reperfusion treatment increases the chances of good recovery. However, in 2007, only 3% of ischemic stroke patients were treated with thrombolysis in Sweden. Patients’ late arrival to hospital was considered to be one of the reasons for the low treatment rate. The aim of the first study was to evaluate if delay to treatment could be decreased with high priority dispatch of ambulance and thus increase the number of patients eligible for thrombolytic treatment. As high priority of suspected stroke patients is dependent on identification of stroke, the following studies aimed to evaluate identification of stroke. Study I: Patients (n 942) with suspected stroke within 6 h, aged 18-85 were randomized from EMCC or ambulance to intervention, Priority 1 alarm or control, Priority 2. The intervention group randomized from EMCC arrived to hospital 13 minutes (p <0.001) earlier, and 26 minutes (p <0.001) earlier to stroke unit compared to the control group. Furthermore, twice as many patients in the intervention group (35%, p <0.001) were treated with thrombolysis compared to the patients in the control group (17%). The conclusion of the study was that higher priority, both pre- and in-hospital is favorable for patients with acute stroke. Study II was a descriptive study of the use of the Face-Arm-Speech-Time test (FAST) in identification of stroke by the EMCC and the ambulance in the patients included in Study I. In all, 52% of the patients were correctly identified as stroke/TIA. The EMCC included 71% of the patients with stroke/TIA diagnosis and the ambulance included another 29%. At least one FAST symptom was positive in 64% of the included patients. The positive predictive value, PPV, for FAST was 56% in the EMCC included patients and 74% in the ambulance included patients. The conclusion was that FAST is not enough to support identification of stroke in emergency calls. The study demonstrated that more information of how stroke is expressed in emergency calls concerning stroke is needed to improve identification. Study III was a descriptive study of symptoms expressed by the caller in emergency calls concerning stroke of the 179 emergency calls included 64% were dispatched as stroke. Speech disturbance (54%), fall or lying position (38%) and altered mental status (27%) were the most common symptoms in calls. FAST symptoms were presented in 64% of the calls and were more commonly presented in calls dispatched as stroke. The FAST symptoms were presented spontaneously by the caller in 90 %. Fall or the patient being in a lying position (66%) was the most dominating problem presented in the stroke calls dispatched as non-stroke. These result show that FAST is rarely asked for and that the calls dispatched as non-stroke often were presented as a fall or the patient being in a lying position. Questions about FAST symptoms in emergency calls with fall/lying position or altered mental status presented may improve identification of stroke. Study IV was a qualitative study of obstacles and facilitators in communication and interaction of the participants in emergency calls concerning stroke using interpretive phenomenology. Of the 68 emergency calls from Study III where fall/lying position were presented, 29 calls were analyzed. The dispatch codes were blinded in the first step of analysis, 13 calls were dispatched as stroke and 16 as non-stroke. The nurses’ expertise skills were the identified aspect that could be decisive in identification of stroke. Other important findings were aspects of the first call-taker and nurse that can be influenced to improve identification, such as authority, competence and coaching strategies. The result indicated need of education and training to improve identification of stroke and to support the process of developing expertise skills.

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