Xenon and the Inflammatory Response to Cardiopulmonary Bypass in the Rat

Objective: The purpose of this study was to investigate the effect of xenon on the inflammatory response to cardiopulmonary bypass. Design: Prospective, randomized experimental study. Setting: University research laboratory. Participants: Sprague-Dawley rats. Interventions: After surgical preparation, rats were randomly divided into 4 groups: (1) SHAM rats were cannulated but did not undergo cardiopulmonary bypass; (2) cardiopulmonary bypass rats were subjected to 60 minutes of cardiopulmonary bypass using an oxygenator receiving a 30% O 2, 65% N 2, and 5% CO 2 gas mixture; (3) MK801 rats received MK801 (0.15 mg/kg intravenous) 15 minutes before 60 minutes of cardiopulmonary bypass with the same gas mixture; and (4) xenon rats underwent 60 minutes of cardiopulmonary bypass receiving a 30% O 2, 60% xenon, 5% N 2, and 5% CO 2 gas mixture. Measurements and Main Results: All bypass groups showed elevations in both cytokines compared with the SHAM-operated group. However, the inflammatory response to cardiopulmonary bypass in the group receiving xenon was no different from the other bypass groups. Conclusions: Xenon appears to have no effect on the inflammatory response to cardiopulmonary bypass, making its previously described neuroprotective effect during cardiopulmonary bypass likely independent of any inflammation modulation.