This prospective observational study aims to evaluate whether non-invasive hemodynamic parameters, including the plethysmographic variability index (PVI) and perfusion index (PI), can predict post-induction hypotension in patients undergoing diagnostic direct laryngoscopy under general anesthesia. Patients aged 18-75 years with ASA physical status I-III scheduled for elective direct laryngoscopy will be included. PVI and PI values will be recorded before anesthesia induction and in the early post-induction period. The relationship between these indices and the decrease in mean arterial pressure after induction will be analyzed to determine their predictive value for hypotension.
Scheduled to undergo elective direct laryngoscopy under general anesthesia Body mass index (BMI) between 18 and 40 kg/m² ASA physical status classification I-III Provision of written informed consent after being informed about the study
Severe arrhythmias Advanced heart failure Severe valvular heart disease Preoperative shock or hemodynamic instability requirement for continuous vasopressor or inotropic infusion Significant peripheral vascular disease affecting peripheral circulation