Unilateral spinal anaesthesia with hyperbaric bupivacaine

Area of Science:

• Anesthesiology
• Neurosurgery
• Orthopedic Surgery

Background:

• Unilateral spinal anesthesia requires precise local anesthetic dosage and patient positioning.
• Optimal parameters for hyperbaric bupivacaine and lateral decubitus duration remain undetermined.
• This study aimed to establish ideal conditions for unilateral spinal blocks.

Purpose of the Study:

• To determine the ideal dosage of hyperbaric bupivacaine for unilateral spinal anesthesia.
• To ascertain the optimal duration for maintaining the lateral decubitus position.
• To evaluate the efficacy of unilateral spinal blocks for lower extremity surgery.

Main Methods:

• Ninety patients undergoing lower extremity surgery received spinal blocks randomized into 9 groups.
• Groups varied by hyperbaric bupivacaine volume (1.5, 2, or 2.5 ml of 0.5%) and lateral decubitus duration (5, 10, or 15 minutes).
• Sensory and motor block onset and regression were assessed on dependent and non-dependent sides.

Main Results:

• Higher bupivacaine volumes (2.5 ml) resulted in faster block progression and longer duration on the non-dependent side, with 10-20% hypotension incidence.
• 2 ml of 0.5% hyperbaric bupivacaine provided satisfactory block level and duration for surgery.
• 1.5 ml of 0.5% hyperbaric bupivacaine showed slower progression, shorter duration, and lower block levels.

Conclusions:

• For unilateral spinal anesthesia in lower extremity operations, 2ml 0.5% hyperbaric bupivacaine is appropriate for above-knee procedures.
• 1.5 ml 0.5% hyperbaric bupivacaine is suitable for below-knee procedures.
• Maintaining the lateral decubitus position for 10 minutes is recommended for both dosages.