JMIR Publications

ABSTRACT

Background:

Most people do not recognize symptoms of neurological and cardiac emergencies in a timely manner, leading to delays in hospital arrival and timely access to efficacious therapies. We created a smartphone application to help emergent symptom recognition and evaluation for stroke or myocardial infraction (MI). The ECHAS (Emergency Call for Heart Attack and Stroke) app guides users to assess their risk of stroke, MI, or related conditions through evidence-based questions and a finger-tapping test for neurological assessment.

Objective:

As an initial step in the accuracy assessment of the app, we designed this cross-sectional study to evaluate the sensitivity of the app, since the most dangerous output of the app would be failure to recognize the need for emergency evaluation. Specificity is also of importance, but the consequences of low specificity are less dangerous than those of low sensitivity. We evaluated sensitivity in a cross-sectional study performed in patients who had presented with stroke or MI symptoms to the Emergency Department (ED). A future study of specificity is planned in patients who do not require emergency ED evaluation.

Methods:

In this single-center study, we enrolled patients presenting with symptoms of possible stroke, myocardial infarction, or related conditions. The assessment by the ECHAS app consisted of a series of evidence-based questions regarding symptoms and a phone-based finger-tapping test to detect unilateral weakness. The primary outcome was the sensitivity of the ECHAS app in detecting the need for ED evaluation. The secondary outcome was the sensitivity of the ECHAS app in detecting the need for hospital admission. Two independent and blinded board-certified physicians reviewed the medical record and adjudicated the gold standard for appropriate need of ED evaluation. For evaluation of usability, we surveyed patients using open-ended prompts and Likert scales to assess opinions on ease of use, benefits, and drawbacks of the app.

Results:

We enrolled 202 patients (57 with stroke-like, 145 MI-like symptoms). The ECHAS app had a sensitivity of 0.98 for identifying patients in whom ED evaluation was appropriate. The app had a sensitivity of 1.0 for identifying patients who were admitted to the hospital because of their ED evaluation. Patients completed the evaluation on the app in an average of 111 seconds (SD 60 seconds) for the stroke pathway and 60 seconds (SD 33 seconds) for the MI pathway. Patients reported that app was easy to use and valuable for personal emergency situations at home.

Conclusions:

The ECHAS app demonstrated a high sensitivity for detection of patients who required emergency evaluation for symptoms of possible stroke or MI. This study supports the need for a study of specificity of the app, and then a prospective trial of the app in patients at increased risk of MI and stroke.