[Hemodynamic effects of spinal anesthesia with 2% lidocaine in comparison to 0.5% isobaric bupivacaine].

Background: Our study compared the haemodynamic changes after spinal anesthesia with 2% lignocaine and 0.5% plain bupivacaine.

Methods: A controlled, randomized trial was performed on 30 patients scheduled for arthroscopic knee surgery. 2% lignocaine and 0.5% plain bupivacaine were used for spinal anaesthesia. We measured cardiac output (electrical bioimpedance cardiography), blood pressure and development of sensory blockade before and for 25 minutes after spinal anaesthesia.

Results: In patients developing a sensory block below T6 there were no differences between both anaesthetics in haemodynamic parameters. But in patients developing a sensory block at or above T6 there was a greater drop in mean arterial pressure and cardiac output and a faster decrease in heart rate for bupivacaine compared to patients receiving Lignocaine.

Conclusion: In patients developing a sensory block at or above the T6 dermatome, the decrease in cardiac output and mean arterial pressure in the first 25 min after spinal anaesthesia is smaller when 2% lignocaine rather than 0.5% bupivacaine is used for blockade.