The volatile anesthetic sevoflurane inhibits activation of neutrophil granulocytes during simulated extracorporeal circulation

Abstract

Extracorporeal circulation (ECC) is an essential tool for the execution of cardiac operations. However, ECC is also associated with undesirable side effects. These include the induction of a systemic inflammatory response associated with leukocyte activation and cytokine release as well as potentially life-threatening complications. The volatile anesthetic sevoflurane has been reported to exert anti-ischemic and anti-inflammatory effects. We therefore investigated whether sevoflurane modulates the ECC-triggered inflammatory response.Heparinized human blood was circulated for 90min in a normothermic (37°C) ex vivo ECC circuit. An air–oxygen mixture was administered via an oxygenator in controls (n=5). Sevoflurane (2vol.%) was added to the gas mixture in a second group (n=5). At baseline and after 30, 60 and 90min of ECC, blood samples were taken. In each sample whole blood counts were determined. Expression of the activation-indicating Mac-1 receptor on granulocytes and monocytes as well as leukocyte–platelet aggregate formation was measured in flow cytometry. Levels of the granulocyte activation marker PMN-elastase and of the cytokines IL-1β, IL-8 and TNF-α were analyzed using ELISA.ECC induced significant increases in Mac-1 expression on granulocytes (p<0.001) and PMN-elastase release (p<0.001). Sevoflurane decreased granulocyte Mac-1 expression during ECC (p<0.05) and inhibited the ECC-induced PMN-elastase release (p<0.05). Sevoflurane had no effect on whole blood cell counts, leukocyte–platelet aggregate formation and cytokine release during ECC.Sevoflurane inhibits granulocyte activation during ex vivo ECC and therefore has the potential to decrease the ECC-triggered inflammatory response. This promising finding warrants further investigation under clinical conditions.