Ventilation according to the open lung concept attenuates pulmonary inflammatory response in cardiac surgery

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response, which is correlated with outcome. We hypothesized that ventilation according to the open lung concept (OLC) attenuates cytokine release.

A prospective, single center randomized controlled clinical study containing 62 patients scheduled for elective coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. Before surgery, patients were randomly assigned to three groups: (1) conventional mechanical ventilation (CV), (2) OLC started after arrival on the ICU (late open lung, LOL), and (3) OLC started directly after intubation (early open lung, EOL). In both OLC groups, recruitment maneuvers were applied until PaO(2)/FiO(2)>50. The CV group received no recruitment maneuvers. Interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma were measured preoperatively, immediately after cessation of CPB, and 3h, 5h, 24h, 2, and 3 days after cessation of CPB.

CPB caused a significant increase of IL-6, IL-8, and IL-10 in all groups. Thereafter, IL-8 decreased significantly more rapidly in both OLC groups compared to CV. IL-10 decreased significantly more rapidly after CPB only in the EOL group, compared with CV. Three hours after cessation of the CPB, IL-10 was already comparable with preoperative levels in the EOL group, but not in the LOL or CV group. IL-6, TNF-alpha, and IFN-gamma did not differ significantly between groups.

OLC ventilation leads to an attenuated inflammatory response, presumably by reducing additional lung injury after cardiac surgery. Studies on cytokines after cardiac surgery should take these findings into account.