Alveolar Recruitment in Brain Injury

Patients with severe brain injury comprise a significant portion of admissions to critical care units. These patients are unable to adequately protect their airways and are usually intubated and mechanically ventilated. The goal of mechanical ventilation in patients with brain injury is to optimize blood gas exchange while minimizing intrathoracic pressure to avoid interference with cerebral venous drainage.Over the last 20 years, a plethora of experimental and clinical data have shown that mechanical ventilation can cause or aggravate lung damage in patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). The aim of this pilot study was to assess the effects of a single standardized recruitment maneuver (RM) on oxygenation and on systemic and cerebral hemodynamics in severe brain injury patients with ALI/ARDS.

Only patients with brain injury, as defined by a Glasgow Coma Score <13, admitted into the Trauma and Surgical intensive care unit (ICU) will be studied.

After obtaining informed consent, a RM will be performed by switching the ventilator from assist/control ventilation to continuous positive airway pressure (CPAP) and applying a pressure of 40 cmH2O for 40 sec (11). After the RM, patients have been ventilated in pressure control ventilation and PEEP will be gradually reduced in decremental steps every 3 respiratory cycles starting with PEEP at 30 cm H2O, maintaining a maximum peak pressure of 40 cmH2O during this procedure until pre-RM PEEP levels are achieved. The RM will be discontinued if any of the following changes developed during the procedure: (i) ≥20% changes in baseline systemic blood pressure, (ii) ICP ≥20 mmHg, or (iii) SaO2 ≤90%. After the RM is performed, respiratory mechanics, arterial and SjO2 blood samples and systemic and cerebral hemodynamics will be obtained at 30 min and 8 hours.