CAROTID DOPPLER AND CEREBRAL OXIMERY IN POST CARDIAC ARREST ICU PATIENTS

Out-of-hospital cardiac arrest (OHCA) is one of the most critical conditions in emergency medicine, causing high mortality and severe neurological sequelae due to the sudden cessation of circulation. Among the hundreds of thousands of patients affected worldwide, a significant proportion die or face permanent neurological impairment from hypoxic-ischemic brain injury, even after return of spontaneous circulation (ROSC). Therefore, early and reliable assessment of brain injury after cardiac arrest is of great importance both for clinical decision-making and for the effective use of treatment resources. Various methods are currently used to predict neurological prognosis after cardiac arrest, including computed tomography, magnetic resonance imaging, electroencephalography, and biochemical markers (NSE, S100B). However, some of these methods are expensive, have limited availability, or can be difficult to apply in the management of critically ill patients. In this context, bedside ultrasonography and cerebral oximetry, being applicable at the bedside, non-invasive, and repeatable, stand out as valuable alternative tools for clinicians. Carotid Doppler ultrasonography provides indirect information about cerebral perfusion by measuring parameters such as peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV), pulsatility index (PI), and resistive index (RI) in the common carotid arteries. High PI and RI values indicate increased intracranial pressure or impaired cerebral vasomotor response, and these findings may be associated with poor neurological outcome. Similarly, transcranial Doppler (TCD) performed via the transtemporal approach reflects the integrity of cerebral autoregulation and cerebral perfusion pressure through middle cerebral artery (MCA) flow velocities and pulsatility values. Optic nerve sheath diameter (ONSD) measurement is an increasingly widespread ultrasound application serving as a non-invasive indicator of elevated intracranial pressure. The optic nerve sheath is known to widen in the presence of cerebral edema, and this finding is thought to be associated with neurological deterioration. Non-invasive cerebral oximetry (rSO2) continuously monitors frontal cerebral oxygen saturation, allowing early detection of periods of cerebral hypoxia. Inadequate cerebral oxygenation after cardiac arrest has been shown to be directly associated with poor prognosis. However, comprehensive studies interpreting this parameter together with Doppler ultrasonography findings are still lacking. The primary aim of this study is to prospectively investigate the predictive value of carotid Doppler (internal, external, and common carotid arteries), TCD-MCA, and ONSD measurements, together with non-invasive cerebral oximetry values, for 60-day mortality and neurological outcome (Cerebral Performance Category, CPC scale) in patients admitted to the ICU due to OHCA. Secondary aims include examining the correlations between these parameters and determining the earliest and most reliable prognostic cut-off values. The results of this study are expected to contribute to early neurological prognostication and patient management in ICU patients after OHCA

Inclusion Criteria: * Age 18 years or older Admitted to the ICU after out-of-hospital cardiac arrest Hemodynamically stable PaCO2 35-45 mmHg Exclusion Criteria: * Age under 18 years In-hospital cardiac arrest Anatomical abnormalities or skin lesions preventing carotid or cerebral ultrasonographic measurement Hemodynamic instability