To assess the dose responsiveness of ringer lactate solution in prevention of post-induction hypotension predicted by Ultrasound guided Inferior Vena Cava diameter in patients receiving General anesthesia.

OBJECTIVES Primary - To find the optimum preloading dosage of Ringer Lactate to prevent post induction hypotension.

Secondary - To find the predictive incidence of Post-induction hypotension according to age, gender, type of surgery and comorbidities.

All patients, after Ultrasonographic Inferior vena cava collapsibility index calculation, will receive Lactated Ringer's solution as per body weight and as per their allocated group in the receiving area.

After induction inside the Operating Room, All patients will be monitored continuously using Electrocardiography, pulse oximetry, noninvasive Blood pressure measurement and capnography .

Heart rate, Systolic - Diastolic - Mean blood pressure, Oxygen saturation will be monitored as follows :

1. Baseline parameters - Prior to administration of intravenous Ringer's lactate solution
2. T0 (after administration of intravenous Ringer's lactate solution but prior to induction of anaesthesia),
3. T1-T10 (every minute for first 10 mins after induction of anaesthesia) Our institutional standard practice of induction of Anaesthesia with Fentanyl (2 μg/kg), Propofol (2 mg/kg) and Vecuronium (0.1mg/kg ) will be followed and intubation will be done only after first 10 mins post induction.

Amount of Mephentermine needed to correct hypotension despite RL infusion will also be calculated.

Inclusion Criteria:

• Age ≥ 18 years American Society of Anesthesiologists (ASA) Physical status classification system group I and II Elective surgery under General anesthesia

Exclusion Criteria:

• Age <18 and > 65 American Society of Anesthesiologists (ASA) Physical status classification system group III and IV Systolic blood pressure ≥ 180 mmHg Systolic blood pressure < 90 mmHg Pregnant women Patients with abdominal mass or ascites Emergency surgery