Predicting 28-Day Survival in OHCA Patients

The demographic profile of each patient was documented, including age and sex, to examine potential associations with survival and neurological outcomes.

Data on pre-existing chronic conditions were recorded, such as hypertension, diabetes mellitus, coronary artery disease, chronic kidney disease, and malignancy, in order to assess their potential impact on prognosis following OHCA.

Several prehospital factors were evaluated, including whether the cardiac arrest was witnessed, whether bystander CPR was performed, the time from collapse to the initiation of CPR, and the time from collapse to EMS arrival. Additionally, the durations of no-flow (i.e., time without any CPR) and low-flow (i.e., time with CPR but without ROSC) were noted. The initial cardiac rhythm was categorized as ventricular fibrillation or pulseless ventricular tachycardia (VF/pVT), asystole, or pulseless electrical activity (PEA). Airway management methods used in the field were documented and classified as bag-valve-mask (BVM), supraglottic airway devices (SGAs), or endotracheal intubation (ETI). Other recorded interventions included prehospital defibrillation, administration of epinephrine (including total dosage), and use of mechanical chest compression devices. Whether ROSC was achieved prior to arrival at the emergency department was also noted.

These included white blood cell count (WBC), hemoglobin level, platelet count, mean platelet volume (MPV), and differential counts such as neutrophils, monocytes, and eosinophils.

Measurements included creatinine, urea, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), sodium, potassium, chloride, calcium, and troponin-I levels.

The primary clinical outcomes recorded for each patient included return of spontaneous circulation (ROSC), 28-day survival or mortality, and neurological status, which was later assessed using the Cerebral Performance Category (CPC) scale.