Protective Ventilatory Strategy in Severe Acute Brain Injury

Acute respiratory distress syndrome (ARDS) occurs in almost 20% of patients with severe acute brain injury and is associated with increased morbidity and mortality. A massive increase in sympathetic activity and an increased production of proinflammatory cytokines released into the systemic circulation are the most important recognized mechanisms. Altered blood brain barrier after injury causes spillover of inflammatory mediators from the brain into the systemic circulation leading to peripheral organs damage. The adrenergic surge induces an increase in vascular hydrostatic pressure and lung capillary permeability, causing an alteration of alveolar capillary barrier with fluid accumulation, resulting in ARDS. The main goal of mechanical ventilation after acute brain injury are the maintenance of optimal oxygenation, and a tight control of carbon dioxide tension, although ventilatory settings to be used to obtain these targets, while avoiding secondary insults to the brain, are not clearly identified. Protective ventilatory strategy has been positively evaluated first in patients with ARDS, and then in those undergoing cardiopulmonary bypass or lung resection surgery, or in brain death organ donors, but data on the effect of protective mechanical ventilation on patients with acute brain injury are still lacking even if this is a population with recognized risk factors for ARDS. Therefore, the primary aim of this multi-center, prospective, randomized, controlled trial is to investigate whether a protective ventilatory strategy, in the early phase after severe acute brain injury, is associated with a lower incidence of ARDS, avoiding any further damage to the brain. Secondary aim is to evaluate if a protective ventilatory strategy is associated with reduced duration of mechanical ventilation, incidence of organ failure, intensive care unit length of stay, and lower concentrations of plasma inflammatory cytokines, without adversely affect in neurological outcome.