: Comparative evaluation of incidence of hypotension in unilateral versus bilateral spinal anaesthesia in patients undergoing percutaneous nephrolithotomy.

**Study Title:**Comparative evaluation of efficacy of unilateral versus bilateral spinal anaesthesia in patients undergoing percutaneous nephrolithotomy.

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Study Design:

• Type Randomized controlled trial
• Location ESIC Medical College and Hospital, Faridabad, Haryana
• Duration October 2025 to March 2027

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Participants:

• Inclusion

• Adults aged 18–60 years

• ASA physical status I or II

• Scheduled for elective percutaneous nephrolithotomy

• Exclusion

• Contraindications to spinal anaesthesia (e.g., coagulation disorders, infection, allergy, increased intracranial pressure)

• Pregnant/lactating females

• BMI > 30 kg/m²

• Expected surgery duration > 2 hours

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Sample Size

• Total of 80 patients

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Group Allocation

• Group U Unilateral spinal anaesthesia (n=40)
• Group BBilateral spinal anaesthesia (n=40)

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Objectives

• Primary Objective

• Compare incidence of hypotension between the two groups

• Secondary Objectives

• Incidence of bradycardia

• Spinal block characteristics:

• Sensory onset, level, duration

• Motor onset, level, duration

• Total dose of mephentermine required

• Duration of anaesthesia

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Assessment & Analysis

• Data will be compiled and analyzed statistically to evaluate outcomes.