Role of Echocardiography in predicting sub-arachnoid block induced hypotension in elective lower segment cesarean section patients: a prospective observational study.

Eligible participants, i.e., term pregnant women scheduled for elective cesarean section under spinal anesthesia, will be recruited consecutively after obtaining written informed consent. Patient will be shifted into the operating theatre and placed on the table with 45 degrees back elevation. Baseline demographic details and vital signs (heart rate and blood pressure) and will be recorded in the supine position.  Echocardiography will be performed and the parasternal long axis (PLAX), parasternal short axis (PSAX) and  apical 5-chamber (A5C) views identified. Echocardiography will  be performed by the same Consultant to avoid inter-observer bias. The echocardiographic parameters namely:  LVOT(Left ventricular outflow tract) VTI, LVEDA, LVOT Diameter are measured. The patient is then placed in the supine position with wedge ( using a standard wedge ensuring 15 degrees tilt measured using a goniometer) and the parameters are recorded after resting the patient in the position for 3 min. Then the back of the patient will be made supine (Passive leg raise (PLR)) and the echo parameters recorded  after 90 seconds. These values will be used to calculate VTI% and LVEDA%, which reflect hemodynamic changes with position. MAP and HR will be continuously recorded during the USG measurements. Following ultrasound recording, the patient will be given intravenous fluid bolus of 50 mL/Kg (Ringer’s lactate or Normal Saline). Spinal anesthesia will be administered using 2 cc of 0.5% Bupivacaine hyperbaric in the left lateral position, and the patient will be placed in the supine position with a 15° left lateral tilt. Mean arterial pressure (MAP) and heart rate will be monitored at 1-minute intervals until delivery or upto 10 min following spinal anesthesia administration. Hypotension will be defined as a >20% decrease in MAP from baseline. The occurrence of hypotension, use of vasopressors (e.g., phenylephrine), and any maternal adverse effects (such as nausea or dizziness) will be recorded. All findings will be entered in a structured case record form, and participants will be categorized into hypotension and normotension groups for subsequent analysis.