Selective pulmonary pulsatile perfusion with oxygenated blood during cardiopulmonary bypass attenuates lung tissue inflammation but does not affect circulating cytokine levels

Abstract

Objective: Improved respiratory outcome has been shown after selective pulsatile pulmonary perfusion (sPPP) during cardiopulmonary bypass (CPB). No contemporary study has analysed the impact of sPPP on alveolar and systemic inflammatory response in humans. Methods: Sixty-four patients undergoing a coronary artery bypass graft (CABG) were randomized to sPPP or standard CPB (32 patients each). An alveolar-arterial oxygen gradient (A-aDO. 2) was measured preoperatively (T0), at ICU arrival (T1), 3 h postoperatively (T2) and postextubation (T3). The bronchoalveolar lavage (BAL) was collected at T0, T1 and T2. White blood cells (WBCs), neutrophils, mononucleates and lymphocytes in BAL infiltrates were compared between the two groups. A cytokine assay for interleukin-1 (IL-1), IL-8, tumour necrosis factor alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), growth regulated oncogene-alpha (GRO-α) and interferon (IFN)-γ was collected from the BAL and peripheral blood at the same time-points. Repeated-measure analysis of variance and non-parametric statistics were used to assess the between-group and during time differences. Results: The two groups proved comparable for perioperative variables. A-aDO2 proved better after sPPP (group-P = 0.0001; group × time-P < 0.0001). BAL infiltrates after sPPP showed lower WBCs, neutrophils and lymphocytes (group-P = 0.0001, group × time-P = 0.0001 for all) together with higher mononucleates (group-P = 0.0001, group × time-P = 0.0001). Proinflammatory cytokines and chemokine MCP-1 were lower in BAL after sPPP (group-P = 0.005, 0.034, 0.036 and 0.005, and group × time-P = 0.001, 0.009, 0.001 and 0.0001 for IL-1, IL-8, TNF-α and MCP-1, respectively), whereas the immune modulator IFN-γ significantly augmented after sPPP (time-P = 0.0001) but remained stable after the standard CPB (time-P = 0.101, group-P = 001, group × time-P = 0.0001). Indeed, serum cytokines were not different in the two groups during the study (P = NS at single time-points and as a function of time). Conclusions: sPPP attenuates alveolar inflammation, as demonstrated by the lower neutrophilic/lymphocytic alveolar infiltration, and the secretion of anti-inflammatory rather than proinflammatory mediators. © The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.