LIDOCAINE IMPROVING THE CEREBRAL PROTECTION BY RETROGRADE CEREBRAL PERFUSION

Objective To determine whether lidocaine can improve the cerebral prot ection provided by retrograde cerebral perfusion. Methods Sixteen mong rel dogs were placed on cardiopulmonary bypass and cooled to 20 degree s C. Retrograde cerebral perfusion was then carried out for 120 minute s, with the external jugular Venous pressure kept at 3.33 kPa. Cardiop ulmonary bypass was resumed, and the animals were rewarmed to 36 degre es C. The animals were divided into two groups. In the lidocaine group (n = 8), lidocaine was administrated continuously throughout the expe riment. In the control group (n = 8), normal saline was given at the s ame rate. Results In both groups, cerebral tissue creatine phosphate a nd adenosine triphosphate concentrations and energy charge increased b y the end of hypothermic cardiopulmonary bypass, decreased continuousl y during retrograde cerebral perfusion, and recovered gradually after resuming cardiopulmonary bypass. Nevertheless, they recovered to signi ficantly higher levels in the lidocaine group than in the control grou p (creatine phosphate: 2.44 +/- 0.53 versus 1.61 +/- 0.49 mu mol/g wet weight, P = 0.006; adenosine triphosphate: 0.71 +/- 0.18 versus 0.50 +/- 0.17 mu mol/g wet weight, P = 0.029; energy charge: 0.59 +/- 0.10 versus 0.48 +/- 0.09, P = 0.044) by the end of the experiment. There w as no significant difference between the two groups in the cerebral ti ssue water content (control group: 77.6% +/- 1.9%; lidocaine group: 77 .6% +/- 1.3%). Conclusion Continuous lidocaine infusion accelerates th e recovery of cerebral tissue high energy phosphate contents after res uming cardiopulmonary bypass, but it has no effect on the formation of cerebral edema after retrograde cerebral perfusion.