Inflammatory response during simulated extracorporeal circulation with addition of nitric oxide

Background. Heart operations performed with extracorporeal circulation (ECC ) are associated with an inflammatory response. This response is partially due to granulocyte activation. Leukocyte derived free radicals are Involved in tissue injury, The purpose of this study was to observe whether nitric oxide influence the inflammatory response during simulated ECC. Methods. In a model of simulated extracorporeal circulation, fresh whole hu man blood mixed with Ringer's solution was circulated through a heart-lung machine for three hours. In five circuits NO was added to oxygen/air mixtur e (group N), while five other circuits were ventilated with oxygen/air mixt ure (group C). The methods for estimating the inflammatory response were de termination of oxygen free radicals production capacity, using chemilumines cence,and measurements of concentration of granulocyte derived proteins (my eloperoxidase and human neutrophil lipocalin). Results. All measured parameters were similarly independent of additional s upply of nitric oxide almost throughout extracorporeal circulation time. Th e sole significant difference between the two groups was found at an early stage of extracorporeal circulation, when luminol-enhanced chemiluminescenc e in whole blood was higher in the N group (1500, 1470-1950 vs 1038, 750-10 50 in the control group; medians with quartiles). A similar tendency was ob served in lucigenin-enhanced chemiluminescence at 60 min of extracorporeal circulation (625, 560-875 in the N group vs 400, 360-525 in the control gro up; medians with quartiles). Conclusions. Nitric oxide supply does not influence inflammatory response d uring three hours long extracorporeal circulation, although some protective effect on hydrogen peroxide production in whole blood was detected in the initial phase of extracorporeal circulation.