Résumé
BACKGROUND: severe brain-injured patients are traditionally maintained in half-seated position (HSP). However, the temporary transitions from the HSP to the lying position (LP) are necessary during management of these patients. We sought to assess in patients with a severe TBI, the impact of the LP on cerebrovascular dynamics and global as well as regional cerebral oxygenation within first week.METHODS: 24 patients with a severe closed TBI and managed with an ICP monitoring were included in our study. For each patient, a positioning manoeuvre of 30 minutes in LP was daily performed during the first week. Cerebral perfusion parameters (ICP, CPP, Vm, PI) and cerebral oxygenation parameters (rScO2, SvjO2) were compared in HSP (30°) and LP (0°). Mixed models were performed to highlight the effect of position on these variables. RESULTS: on day 1 after the trauma, following 30 minutes in LP, ICP and CPP were increased compared to HSP (respectively +6 mmHg [4-7] and +10mmHg [5-14]). A raising of Vm was also observed in LP (+6 cm/s [0–11]; P=0.01) in association with a decrease of PI in LP (-0.1 point [-0.3-0]; P=0.02). Similarly, rScO2 was increased in LP (+3 points [2-5 points]; p<0,001). Mixed models analysis confirms the association between the position and the value of CPP, Vm, rScO2, PI, with more favourable conditions in the LP. There was no influence of cerebral autoregulation status or neurologic outcome. CONCLUSION: moderate increasing of ICP during routine nursing care in LP did not reflect an impairment of cerebral hemodynamic and cerebral oxygenation conditions in the first week after TBI.