Inflammatory response of neutrophil granulocytes and monocytes after cardiopulmonary bypass in pediatric cardiac surgery

Abstract

Objective. To determine whether the activation state of polymorphonuclear neutrophils (PMNs) and monocytes contributes to the inflammatory response after cardiopulmonary bypass (CPB) in pediatric cardiac surgery.

Design. Observational prospective clinical study.

Setting. Pediatric intensive care unit of a university hospital.

Patients. Twenty pediatric patients before and after open heart surgery with CPB.

Measurements. Cell counts of circulating PMNs and monocytes as well as phenotypic and functional analysis of these cells, and plasma levels of myeloperoxidase.

Results. Levels of myeloperoxidase (a marker of PMN degranulation) were significantly elevated after CPB (2.9±1.6 ng/ml before CPB versus 13.7±6.5 ng/ml after CPB, p=0.0001). However, PMN function, as measured by surface expression of CD11b/CD18 and phagocytic respiratory burst, was reduced. In contrast, the phagocytic respiratory burst of circulating monocytes was increased in some patients and there was a correlation with the increase of monocyte cell count after CPB (r=0.63, p=0.015).

Conclusions. After the end of CPB, there was an ongoing inflammatory process. In particular, there was an activation of monocytes after the end of CPB.