ARDS in the brain-injured patient: what’s different?

Excerpt

Management of ARDS in patients with acute brain injury (ABI) differs in several ways from non-neurological subjects. Ventilation must be doubly protective, for the lung and the brain. Adjustment of ventilator settings is dictated by the interactions of positive-pressure ventilation with intracranial circulation, brain compliance, and cerebral autoregulatory reserve, aiming to avoid intracranial pressure (ICP) increase and inadequate cerebral blood flow (CBF). Established therapies of refractory hypoxemia such as prone positioning appear feasible but require rigorous control of ICP. Clinical data on the use of extracorporeal decarboxylation to control hypercapnia in patients with ABI and intracranial hypertension and to manage refractory hypoxemia with extracorporeal membrane oxygenation (ECMO) remain limited. ABI-related ARDS has distinct mechanisms, determined by a cross talk between neuroinflammation, sympathetic activation, and systemic immune response, and may be exacerbated by specific neurointensive care interventions, such as CBF augmentation (Fig. 1). These differences justify a different approach to ARDS after ABI and explain why brain-injured patients are generally excluded from randomized controlled trials of ARDS.

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