Prehospital ETI in OHCA

This prospective observational cohort study was conducted in the ED of Haseki Training and Research Hospital between July 1, 2025, and December 31, 2025. Patients presenting to the ED with cardiac arrest during the study period were screened for eligibility. All patients received advanced cardiac life support (ACLS) in accordance with the 2025 European Resuscitation Council (ERC) guidelines.

Data collected for each patient encompassed demographic characteristics (age, sex, and body mass index [BMI]) and comorbid conditions, including hypertension, diabetes mellitus, coronary artery disease, chronic kidney disease, and malignancy. Prehospital variables included witnessed arrest, bystander CPR, bystander automated external defibrillator (AED) use, no-flow duration, time from collapse to initiation of advanced life support (ALS), time from collapse to hospital arrival, hyperventilation, and initial cardiac rhythm (asystole/pulseless electrical activity [PEA] or ventricular fibrillation/pulseless ventricular tachycardia [VF/pVT]). Prehospital airway data were recorded in two ways: the airway device present on ED arrival (endotracheal tube in place, bag-valve-mask ventilation, or supraglottic airway) and prehospital ETI attempt status (successful ETI, failed ETI attempt, or no ETI attempt). ETI success and the reasons for failed ETI attempts were also recorded, as was the occurrence of prehospital ROSC.

Upon arrival at the ED, body temperature, Glasgow Coma Scale (GCS) score (when assessable), and vasopressor use within the first hour were recorded. Arterial blood gas parameters, including pH, partial pressure of oxygen (PaO2), and partial pressure of carbon dioxide (PaCO2), were also documented. Clinical outcomes included ROSC, 28-day survival status, and neurological outcome.

Patients were classified as survivors or non-survivors according to 28-day survival status. Demographic characteristics, comorbidities, prehospital time intervals, initial rhythm, blood gas parameters, and airway management variables were compared across these groups to identify factors associated with 28-day survival. For airway-specific analyses, patients were further categorized into three groups according to ETI status: successful ETI, failed ETI attempt, and no ETI attempt. Comparisons among these groups were performed to assess differences in demographic and clinical characteristics, prehospital resuscitation variables, ROSC, 28-day survival, and favorable neurological outcome according to ETI status.

Inclusion criteria

• Age ≥18 years
• Out-of-hospital cardiac arrest (OHCA)
• Transport to the emergency department by emergency medical services (EMS)
• Initiated resuscitation/advanced cardiovascular life support (ACLS) by EMS
• Enrollment period between July 1, 2025, and December 31, 2025

Exclusion criteria

• Age <18 years
• In-hospital cardiac arrest
• Cardiac arrest due to major trauma, drowning, drug overdose, or known terminal illness
• Tracheostomy present
• Missing data on primary outcomes or admission laboratory parameters