How accurately can the aetiology of cardiac arrest be established in an out-of-hospital setting? Analysis by “Concordance in Diagnosis Crosscheck Tables”

IntroductionSeveral previous studies have focused on establishing the cause of cardiac arrest (CA) during cardiopulmonary resuscitation (CPR) provided in an out-of-hospital setting.ObjectivesTo analyze the ability of professional advanced life support providers to correctly establish the aetiology of cardiac arrest during out-of-hospital CPR.Study designA retrospective cohort study analysing 211 cases of out-of-hospital cardiac arrest.MethodThe aetiology assumed by out-of-hospital physicians was compared with the diagnosis that was later established by clinicians or pathologists.ResultsCases were sorted into five diagnostic groups and the overall diagnostic concordance was 74.4% (157 of 211 cases). The cardiac aetiology was presumed in 132 out of 211 patients and confirmed in 135 out of 211 patients.However, an analysis of individual cases of the cardiac causes of cardiac arrest revealed diagnostic matches in only 112 cases. Acute myocardial infarction (AMI) or pulmonary embolism (PE), both of which represent cases that can be potentially influenced by thrombolytic therapy, were presumed in 74 (53 + 21) and confirmed in 97 (77 + 20) cases, however with individual diagnostic matches in only 55 cases.ConclusionThis study demonstrates the importance of analysing concordance in presumed and definitive diagnosis of individual cases, since an overall comparison in a cohort of cases may be highly misleading. It introduces the method of the crosscheck table for visualization and comparison of presumed and final diagnoses. The two alternative approaches of inclusion rule for applying the thrombolytic therapy in out-of-hospital care were discussed with regard to the recent TROICA study.