Differentiating between comatose patients resuscitated from acute coronary syndrome-associated and subarachnoid hemorrhage-associated out-of-hospital cardiac arrest.

BACKGROUND: Upon initial evaluation in the emergency department (ED), it is often difficult to differentiate between comatose patients resuscitated following acute coronary syndrome (ACS)-associated and subarachnoid hemorrhage (SAH)-associated out-of-hospital cardiac arrest (OHCA). We assessed the clinical differences between resuscitated comatose ACS-OHCA and SAH-OHCA patients during initial evaluation in the ED.
METHODS: Data of 1259 consecutive OHCA patients were analyzed retrospectively. Of these, 23 resuscitated comatose ACS-OHCA patients and 20 resuscitated comatose SAH-OHCA patients were included in the final analysis. Clinical data obtained during initial evaluation in the ED were compared between groups.
RESULTS: Pulseless electrical activity (PEA) or asystole as the initial cardiac rhythm, female gender, and preserved left ventricular ejection fraction (≥50%) on the echocardiogram were significantly more common in the SAH-OHCA group (p<0.05 each). Although ST-T abnormalities suggesting myocardial damage (ST elevation and/or ST depression) were noted in most patients in both groups via 12-lead electrocardiogram (95%, ACS-OHCA group; 85%, SAH-OHCA group, p=0.50), reciprocal ST depression was significantly more often absent in the SAH-OHCA group (p=0.025). Initial PEA/asystole and presence of 1 other factor was sufficient to differentiate SAH-OHCA patients from ACS-OHCA patients (100% sensitivity, 91% specificity, 95% accuracy).
CONCLUSIONS: Initial ED evaluation is sufficient to differentiate between comatose ACS-OHCA and SAH-OHCA patients prior to further diagnostic work-up (e.g. emergent coronary angiography and head computed tomography).