Carotid Doppler Changes After Passive Leg Raising for Prediction of Post-Induction Hypotension in Gastrointestinal Tumor Surgery

The study will be conducted on patients scheduled for elective gastrointestinal tumor surgery. Prior to anesthesia induction, a passive leg raise maneuver will be performed. Carotid artery Doppler parameters and hemodynamic changes will be measured and recorded to evaluate their efficacy in predicting subsequent post-induction hypotension.

Inclusion criteria

• Adults aged 18 years or older
• Patients scheduled for elective gastrointestinal tumor surgery
• Surgery planned under general anesthesia
• Body mass index (BMI) <40 kg/m²
• Written informed consent provided

Exclusion criteria

• Refusal to participate or inability to obtain written informed consent
• BMI ≥40 kg/m²
• Pregnancy
• Emergency surgery
• Difficult intubation
• ASA physical status ≥IV
• Pediatric patients (<18 years)
• Inability to perform carotid Doppler measurements
• Arrhythmia other than continuous sinus rhythm or uncontrolled cardiac arrhythmia
• Severe cardiac dysfunction or left ventricular ejection fraction <40%
• Severe valvular heart disease
• Clinically significant autonomic nervous system disorders
• Inadequate noninvasive blood pressure monitoring or inability to obtain the required hemodynamic measurements
• Active sepsis or systemic inflammatory syndrome
• Severe peripheral vascular disease or significant carotid artery stenosis (>50%)
• Severe pulmonary disease or advanced respiratory failure
• Implanted cardiac device (pacemaker/ICD)
• Baseline mean arterial pressure (MAP) <65 mmHg
• Preoperative systolic blood pressure >190 mmHg or diastolic blood pressure >110 mmHg