Comparison of differential blockade during spinal anesthesia using isobaric vs. hyperbaric lidocaine 2%

Area of Science:

• Anesthesiology
• Pharmacology
• Neurosurgery

Background:

• Spinal anesthesia is a common technique for lower limb surgeries.
• Lidocaine is a widely used local anesthetic for spinal anesthesia.
• The baricity of anesthetic solutions can influence the spread and density of the block.

Purpose of the Study:

• To compare the sensory, motor, and sympathetic blockade of hyperbaric versus isobaric 2% lidocaine (60 mg) administered intraspinally.
• To evaluate the effect of baricity on the extent and characteristics of spinal anesthesia.

Main Methods:

• A randomized, double-blind study involving 40 patients undergoing elective surgery.
• Patients received either hyperbaric or isobaric 2% lidocaine (60 mg) intraspinally.
• Sensory, motor, and sympathetic blockade levels were assessed at multiple time points.

Main Results:

• No significant difference in the maximal cephalad spread of sensory or sympathetic blockade between hyperbaric and isobaric lidocaine.
• Hyperbaric lidocaine resulted in a more pronounced sensory (pinprick, cold) and motor block on the dependent side compared to the non-dependent side.
• No differences in sympathetic block height were observed between the two groups.

Conclusions:

• The baricity of 60 mg of spinal lidocaine does not influence the cephalad spread of sensory or sympathetic blockade.
• Hyperbaric lidocaine demonstrates a localized effect, enhancing sensory and motor blockade on the dependent side.
• These findings have implications for optimizing spinal anesthesia techniques based on patient positioning and desired block characteristics.