Neutrophil extracellular traps are not produced in pediatric patients with one-lung ventilation: a prospective, single-center, observational study

Background: One-lung ventilation (OLV) may cause lung injury and induce pulmonary pro-inflammation; this ventilator-induced lung injury is associated with neutrophil infiltration. The infiltrated neutrophils release neutrophil extracellular traps (NETs), which are associated with tissue damage. It is not known whether NETs are involved in the pathogenesis of one-lung injury and if they could be a potential therapeutic target. In the present study, we quantified NETs in bronchoalveolar lavage fluid from pediatric patients who underwent OLV and assessed their relationship with prognosis. Methods: Eighteen patients with congenital pulmonary cysts or pulmonary sequestration were enrolled in this prospective monocentric study. Myeloperoxidase (MPO) levels, NET markers [i.e., citrullinated histone-3 (CH-3) and free double-stranded DNA (dsDNA)], and inflammatory cytokine levels in bronchoalveolar lavage fluid were assessed. Continuous variables were compared using the paired t-test. The association of NET concentration in bronchoalveolar lavage fluid and clinical parameters was assessed using linear regression analyses. Results: dsDNA concentration in bronchoalveolar lavage fluid was higher after OLV than before OLV in both the affected lung (0.23 +/- 0.30 vs. 0.97 +/- 1.05, P<0.05) and the healthy lung (0.28 +/- 0.19 vs. 2.45 +/- 2.23, P<0.05). However, there were no significant differences in concentrations of MPO, CH-3, and inflammatory cytokines before and after OLV. Serum interleukin (IL)-6 concentration was higher after OLV than before (t=-3.222, P=0.007). Moreover, no associations between dsDNA concentration in bronchoalveolar lavage fluid and the duration of postoperative mechanical ventilation, postoperative hospital stay, and chest high-resolution computed tomography score were observed. The durations of OLV, anesthesia, and operation, as well as the amount of blood loss, had no significant influence on postoperative dsDNA concentration in bronchoalveolar lavage fluid. Conclusions: NETs in bronchoalveolar lavage fluid are not involved in patients who undergo OLV.