Role of subclavian vein collapsibility index in predicting post spinal hypotension in geriatric patients undergoing below umbilical surgery - A prospective observational study.

The study will be conducted in the Department of Anesthesiology at Sri Manakula Vinayagar Medical College and Hospital as a prospective observational study. All patients will undergo a preoperative examination to check eligibility based on inclusion and exclusion criteria. After explaining the study procedure, informed written consent will be obtained. Patient demographic data such as age, gender, height, weight, and BMI will be recorded. Pre-medication with tablet pantoprazole 40 mg and tablet alprazolam 0.5 mg will be given the night before surgery, and patients will remain nil per oral overnight. On the day of surgery, eligible patients meeting ASA fasting guidelines will be enrolled in the study.

Preoperative ultrasound examination will be done using a Sono Site M-Turbo portable machine with curvilinear and linear probes. The right subclavian vein will be assessed with a linear probe placed in the sagittal plane at the deltopectoral triangle. The subclavian vein collapsibility index (CI) will be calculated as the difference between maximum and inspiratory diameters divided by the maximum diameter, expressed as a percentage. CI measurements will be taken during spontaneous and deep inspiration. Baseline vitals will be recorded before spinal anesthesia is administered per standard protocol. Post-spinal, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate will be recorded every five minutes for 30 minutes. Hypotension, defined as SBP < 90 mmHg, MAP < 60 mmHg, or a 20% fall from baseline, will be managed with IV fluids and vasopressors.

This study aims to evaluate the role of the subclavian vein collapsibility index (SCVCI) in predicting intravascular volume status and the risk of post-spinal hypotension. The subclavian vein is easier to visualize with ultrasound, especially in obese patients and those undergoing abdominal surgeries. Early prediction of hypotension using SCVCI may aid in optimizing perioperative fluid management and improving hemodynamic stability. Additionally, SCVCI assessment could help predict hospital stay duration and recovery, potentially leading to better outcomes in geriatric patients.