Brain-lung interaction: a vicious cycle in traumatic brain injury.

The brain-lung interaction can seriously affect patients with traumatic brain injury, triggering a vicious cycle that worsens patient prognosis. Although the mechanisms of the interaction are not fully elucidated, several hypotheses, notably the "blast injury" theory or "double hit" model, have been proposed and constitute the basis of its development and progression. The brain and lungs strongly interact via complex pathways from the brain to the lungs but also from the lungs to the brain.