Opening Up to Lung Recruitment. Pulmonary Contusion and Derecruitment – The Role of Inflammation

Purpose of review: It was recently reported that a lung protective ventilation strategy resulted in no fatalities in 17 patients with ARDS secondary to lung contusion. Although the efficacy of a lung protective ventilation strategy to reduce mortality in ARDS patients has been demonstrated, the underlying mechanisms for this reduction remain unclear. Recent findings: ARDS is characterized by an inflammatory state of the lung that can be aggravated by mechanical ventilation. Especially mechanical ventilation allowing cyclic opening and closing of unstable alveoli, enhances cytokine release and can even result in loss of compartmentalization. Disbalance in the cytokine response can promote bacterial colonization and result in multiorgan failure. Recent clinical trials and experimental studies have demonstrated that recruitment of collapsed alveoli and stabilization of alveoli using sufficient levels of PEEP can reduce inflammation, bacterial colonization and the number of failing organs, thereby decreasing mortality. Summary: Lung protective ventilation strategies minimizing this cyclic opening and closing by recruiting collapsed alveoli and subsequent stabilization with adequate levels of PEEP offer the clinician a tool to improve patient outcome in ARDS. This benefit is partly mediated by maintaining a ‘natural’ balance in the cytokine response. Future studies should explore this strategy in a randomized prospective study.