The goal of this observational study is to determine the correlation between cerebral oxygenation values measured by near-infrared spectroscopy (NIRS) and other routine monitoring parameters in patients placed in the semi-sitting position.
The primary questions investigated are :
Do NIRS values correlate with heart rate, invasive mean arterial pressure, and end-tidal carbon dioxide?
Do NIRS values reflect changes observed in arterial blood gas analysis?
Are cerebral perfusion-related parameters associated with patients' comorbidities such as diabetes, obesity, and hypertension?
Researchers will compare routine noninvasive monitoring (heart rate, blood pressure, peripheral oxygen saturation) with invasive arterial monitoring and NIRS to assess whether NIRS provides additional information for evaluating cerebral perfusion.
Participants will be monitored for:
Heart rate
Invasive mean arterial pressure
End-tidal carbon dioxide
Arterial blood gas changes
Cerebral oxygenation with NIRS
Patients' comorbidities (e.g., diabetes, obesity, hypertension) will also be recorded, and their association with perfusion-related parameters will be analyzed.
Patients scheduled for orthopedic surgery in the semi-sitting position
ASA physical status I-III
Voluntary participation with informed consent
Patients younger than 18 years
Patients who do not provide consent
History of cerebral ischemia
History of head trauma