Systemic Inflammatory Response During Lung Recruitment Maneuvers in a Newborn Animal Model

Abstract

Background:The benefits of lung recruitment maneuvers (RMs) in adult and pediatric patients undergoing anesthesia have been well documented. However, RMs may induce lung injury and proinflammatory changes. This study assesses the effects of airway pressure steps in lung RMs on the systemic inflammatory response, lung mechanics and arterial blood oxygenation in a healthy-lung porcine model, and evaluates the possibility of RMs extrapolation to human newborns. Material and Methods: Eight healthy-lung newborn male piglets received mechanical ventilation in pressure-controlled mode. The effectiveness of the RM applied was assessed by comparing oxygenation and lung mechanics among the different pressure steps. The levels of blood cytokines: TNF-α, IL-1ß, IL-6, IL-8 and IL-10 were determined before and 60 minutes after the onset of the RM. Results: Maximum positive end-expiratory pressure (PEEP) was 20cmH 2 O with a 35cmH 2 O peak pressure step. Optimum dynamic compliance-PEEP was reached in the descending branch. A significant increase in IL-1ß, IL-6, IL-8 levels was observed after the RM. Neither TNF-α nor IL-10 were elevated by the RM. There was no correlation between respiratory parameters, cardiac index and cytokine plasma levels following the RM. Conclusions: Although this ventilatory strategy induced a systemic inflammatory response, the effects of the RM did not seem to be clinically relevant. The RM applied improved arterial blood oxygenation and lung mechanics. This strategy could be useful in neonatal anesthesia however, further research is warranted before extrapolating this RM to human newborns.