Prone position is a key component to treat hypoxemia in patients with severe Acute Respiratory Distress syndrom. However, most studies evaluating it exclude patients with brain-injuries without any medical evidence.


We planned: a systematic review to determine whether brain-injured patients were excluded in studies evaluating prone position on Acute Respiratory Distress syndrom; a prospective study including consecutive brain-injured patients needing prone position. Our primary endpoint was the evaluation of cerebral blood flow using transcranial Doppler after prone positioning. Secondary outcomes were intracranial pressure, cerebral perfusion pressure and PtiO2.


From 8183 citations retrieved, 120 studies were included in the systematic review. Among them, 90 studies excluded brain-injured patients (75%) without any justification, 16 included brain-injured patients (4 randomized, 7 non-randomized studies, 5 retrospective) and 14 did not retrieve brain-injured data. Eleven patients were included in our pilot study. No reduction of cerebral blood flow surrogates was observed during prone positioning: diastolic speed values (Mean±SD) ranging from 37.7±16.2 cm/s to 45.2 ±19.3 cm/s for the right side (p=0.897), 39.6 ±18.2 cm/s to 46.5±21.3 cm/s for the left side (p=0.569), and pulsatility index ranging from 1.14 ±0.31 to 1.0 ±0.32 for the right side (p=0.145) and 1.14 ±0.31 to 1.02 ±0.2 for the left side (p=0.564) before and during Prone Position.


Brain-injured patients are largely excluded from studies evaluating prone position in Acute Respiratory Distress syndrom. However, cerebral blood flow seems not to be altered considering increasing of MAP during session. Systematic exclusion of brain-injured patients appears to be unfounded and prone position, while at risk in brain-injured patients, should be evaluated on these patients to review recommendations, considering close monitoring of neurological and haemodynamic parameters.