Shedding Light Into The Black Box of Out-of-Hospital Respiratory Emergencies – A Retrospective Cohort Analysis of Discharge Diagnoses, Prehospital Diagnostic Accuracy, And Predictors of Mortality

Abstract

Background: Respiratory distress is one of the most common complaints of patients requiring out-of-hospital emergency services. Determining the precise discharge diagnosis in these circumstances can be challenging due to the wide range of suspected diagnoses. Moreover, these patients appear to have particularly high mortality, but little is currently known about the exact mortality rates associated with specific discharge diagnoses. Our study, therefore, aimed to determine how accurately correct diagnoses are made by EMS physicians in the out-of-hospital setting, identify examination findings that correlate with discharge diagnoses, investigate hospital mortality, and identify mortality-associated predictors.Methods: This retrospective observational study examined emergency medical service (EMS) encounters between December 2015 and May 2016 in the city of Aachen, Germany, in which an EMS physician was present at the scene. Adult patients were included if the EMS physician initially detected dyspnea, low oxygen saturation, or pathological auscultation findings at the scene (n = 719). By linking out-of-hospital data to hospital records, including initial blood gas analysis, a discharge diagnosis was assigned to each EMS encounter, and the outcome was analyzed. Binary logistic regressions were used to search for associations between pathological findings and discharge diagnoses, as well as predictors of hospital mortality.Results: The overall diagnostic accuracy was 69.9% (485/694). The highest diagnostic accuracies were observed in asthma (15/15 ≙ 100%), hypertensive crisis (28/33 ≙ 84.4%), and COPD exacerbation (114/138 ≙ 82.6%), and the lowest accuracies were observed in urinary tract infection (14/35 ≙ 40%), pulmonary embolism (8/18 ≙ 44.4%), and pneumonia (70/142 ≙ 49.3%). The overall hospital mortality rate was 13.8% (99/719). The highest hospital mortality rates were seen in pneumonia (44/142 ≙ 31%) and urinary tract infection (7/35 ≙ 20%). Potential risk factors for hospital mortality identified in this study were reduced vigilance, low oxygen saturation, increasing age, blood gas analysis (BGA) results associated with metabolic acidosis, and an incorrect out-of-hospital diagnosis by the EMS physician.Conclusions: Our data highlight the diagnostic uncertainties and high mortality in out-of-hospital emergency patients presenting with respiratory distress. The identified predictors could help in early detection of patients at risk in the future.