Management and weaning from mechanical ventilation in neurologic patients
In the early phase following severe brain injury (BI), mechanical ventilation (MV) is often needed to prevent airway from aspiration, control PaCO2 and PaO2 and avoid secondary brain insults. Although patients with BI are frequently hospitalized in the intensive care unit (ICU) without respiratory problems, they display longer durations of MV and a challenging weaning process compared to other ICU populations. Historically, the MV settings of BI patients associated high tidal volume with low or no positive end-expiratory pressure (PEEP), for neurological reasons. The extensive data about the beneficial effects of protective ventilation in patients without acute respiratory distress syndrome, have questioned the consequences of such management in BI patients. Recent studies suggest that protective ventilation is safe and could even bear significant impact on morbidity in these patients. The MV weaning process is also challenging, since these patients display a high rate of extubation failure. Recently, new clinical scales of successful extubation have been highlighted combining airway and neurologic operators. A minimal level of arousal should be achieved before extubation, but the Glasgow Coma Score has been inconsistently associated with successful extubation, probably owing to the challenging quantification in intubated patients. Early tracheostomy seems to bear positive effects on morbidity in BI patients. Nonetheless the level of evidence remains poor and no strong recommendations can be made on this topic. Overall, the respiratory bundle of care in BI patients could be readapted with the new data available in the literature. Even if they bear positive impact on morbidity in ICU, their consequences on neurological recovery have yet to be adequately assessed.