Effect of Patient Position on Bupivacaine Dose Requirement and Hemodynamic Stability in Spinal Anesthesia

University of Health Sciences Balikesir Hospital Eduation and Research

Status: Not yet enrolling

Conditions: Bupivacaine; Hemodynamic Changes; Spinal Anesthesia; Patient Positions

Treatments: Drug: Bupivacaine %0.5 (hyperbaric)

Study type: Interventional

Funder types: Other

Identifiers

NCT07376798

hduman

Details and patient eligibility

About

This study compares different combinations of local anesthetic doses and patient positions during spinal anesthesia for urogenital surgery. Spinal anesthesia is a common and safe technique where medication is injected into the lower back to numb the body during surgery.

The study will test two different doses of bupivacaine (a numbing medication): a lower dose (8 mg) and a standard dose (12 mg). It will also test two different patient positions after the spinal injection: lying flat (neutral position) and lying with the head slightly lower than the feet (Trendelenburg position).

Participants will be randomly assigned to one of four groups:

• Group 1: Lower dose + lying flat
• Group 2: Lower dose + head-down position
• Group 3: Standard dose + lying flat
• Group 4: Standard dose + head-down position

The study will measure how well the anesthesia works, how high the numbness spreads in the body, and how it affects blood pressure and heart rate. The goal is to find the best combination of dose and position that provides good anesthesia while keeping blood pressure stable.

This research may help doctors choose the safest and most effective anesthesia approach for each patient based on their individual needs.

Enrollment: 100 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age 18-70 years
• American Society of Anesthesiologists (ASA) physical status classification I-II
• Scheduled for elective urogenital surgery
• Suitable candidate for spinal anesthesia
• Able to read, understand, and provide written informed consent
• Body Mass Index (BMI) less than 35 kg/m²
• Willing to participate in the study

Exclusion criteria

• Contraindications to spinal anesthesia (coagulopathy, infection at injection site, patient refusal)
• History of neurological disease
• Spinal deformity or previous spinal surgery
• History of allergic reaction to local anesthetics (amide-type)
• ASA physical status classification III or higher
• Emergency surgery
• Pregnancy
• Psychiatric illness preventing effective communication
• Refusal to participate in the study
• Unable to understand or provide informed consent

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Factorial Assignment

Masking: Single Blind

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100 participants in 4 patient groups

8 mg Bupivacaine + Neutral Position

Active Comparator group

Description:

Participants will receive 8 mg of 0.5% hyperbaric bupivacaine via spinal anesthesia at L3-4 or L4-5 interspace in sitting position. Immediately after injection, participants will be positioned supine in neutral (horizontal, 0°) position and maintained in this position throughout the procedure. Standard hemodynamic monitoring and management protocols will be applied.

Treatment:

Drug: Bupivacaine %0.5 (hyperbaric)

8 mg Bupivacaine + 10° Trendelenburg

Experimental group

Description:

Participants will receive 8 mg of 0.5% hyperbaric bupivacaine via spinal anesthesia at L3-4 or L4-5 interspace in sitting position. Immediately after injection, participants will be positioned in 10° Trendelenburg position (head-down tilt) and maintained in this position throughout the procedure. Standard hemodynamic monitoring and management protocols will be applied.

Treatment:

Drug: Bupivacaine %0.5 (hyperbaric)

12 mg Bupivacaine + Neutral Position

Active Comparator group

Description:

Participants will receive 12 mg of 0.5% hyperbaric bupivacaine via spinal anesthesia at L3-4 or L4-5 interspace in sitting position. Immediately after injection, participants will be positioned supine in neutral (horizontal, 0°) position and maintained in this position throughout the procedure. Standard hemodynamic monitoring and management protocols will be applied.

Treatment:

Drug: Bupivacaine %0.5 (hyperbaric)

12 mg Bupivacaine + 10° Trendelenburg

Experimental group

Description:

Participants will receive 12 mg of 0.5% hyperbaric bupivacaine via spinal anesthesia at L3-4 or L4-5 interspace in sitting position. Immediately after injection, participants will be positioned in 10° Trendelenburg position (head-down tilt) and maintained in this position throughout the procedure. Standard hemodynamic monitoring and management protocols will be applied.

Treatment:

Drug: Bupivacaine %0.5 (hyperbaric)