Abstract 292: Accuracy of a Dispatch-Directed Breathing Verification Diagnostic Tool as Assessed by Data From Electronic Patient Care Records and Emergency Dispatch Systems

Abstract

Introduction: Identification of sudden out-of-hospital cardiac arrest (OHCA) and delivery of bystander emergency medical dispatcher (EMD)-directed pre-arrival instructions are key elements in the chain of survival. In order to provide instructions, dispatchers must formulate a clinical impression (rather than a definitive diagnosis) after an abbreviated history and dispatcher-directed examination of the scene. Thus, fast and accurate identification tools are imperative in the treatment of OHCA. Hypothesis: A dispatch-directed breathing verification diagnostic tool (BVDxT) accurately identifies inadequate breathing from OHCA. Methods: A retrospective design using EMD data matched to electronic patient care records (ePCRs) from the Salt Lake City Fire Department. The BVDxT, an embedded interface within the dispatch system, allows dispatchers to count breaths as reported by callers and record the rate of 4 consecutive patient breaths. OHCA was defined as non-trauma cases that had paramedic primary impression of cardiac arrest, respiratory arrest, or overdose or a Glasgow Coma Score of 3. Results: A total of 45,007 emergency dispatch cases were matched with the paramedic impressions of 38,258 ePCRs. Of the matched cases, 2660 cases included some use of the BVDxT, 1,365 (51.3%) had used the BVDxT to completion (i.e. breathing rate was recorded during the call) and, of those, 1,248 (91.4%) had complete on-scene paramedic primary or secondary impressions to match to the BVDxT outcomes. Median time using the tool was 28 seconds (IQR: 21-39). Overall, BVDxT identified 68.6% (n = 856/1,248) callers with disordered breathing and paramedics recorded 16.4% (205/1,248) cases of OHCA. BVDxT demonstrated a 70.7% (145/205) sensitivity, and 31.8% specificity for OHCA. Conclusions: Preliminary evidence suggest the BVDxT does well in predicting abdominal breathing condition. Although, by design, emergency dispatch tools tend to have high sensitivity, the low specificity of the tool may over-triage the number of abnormal breathing issues in the field - which may result in a substantial proportion of possible false positives. Changes in patient condition between call receipt and EMS arrival may also impact these findings.