In patients with severe traumatic brain injury, there is limited evidence of the clinical effect of early orthostatic exercise, although such exercise may strengthen systemic or cerebral hemodynamic responses to head-up tilt, thereby minimizing orthostatic intolerance. We measured dynamic cerebral autoregulation (dCA) and the occurrence of orthostatic intolerance after four weeks of regular orthostatic exercise by head-up tilt using a tilt table with integrated stepping using the ERIGO® tilt-table and comparing it to standard care. Thirty-four patients with severe traumatic brain injury admitted to a neurocritical care unit were included in this randomized clinical trial. Middle cerebral artery blood flow velocity (MCAv), non-invasive mean arterial pressure, heart rate and PaCO₂ were recorded; dCA was measured by the non-invasive mean flow index (nMxa). Transition from the supine position to head-up tilt triggered a 10–16% decrease in MCAv and increased nMxa in both groups at all time points (P < 0.05), with no differences between groups. There was no difference in the number of episodes with orthostatic intolerance (5 vs 3; 1 vs 2; 1 vs 0) at baseline, two weeks and four weeks, respectively, and no association between changes in PaCO₂-adjusted nMxa and the occurrence of orthostatic reactions (P = 0.35). Early orthostatic exercise does not affect dynamic cerebral autoregulation and does not protect against orthostatic intolerance in patients with severe traumatic brain injury. Trial registration: ClinicalTrials.gov identifier: NCT02924649. Registered on 3rd October 2016.

对于严重创伤性脑损伤患者，早期直立运动的临床效果证据有限，尽管这种运动可能会加强全身或大脑对抬头倾斜的血流动力学反应，从而最大限度地减少直立不耐受。我们测量了动态大脑自动调节 (dCA) 和 4 周定期直立运动后直立不耐受的发生情况，方法是使用倾斜台抬头倾斜，使用 ERIGO® 倾斜台集成步进，并将其与标准护理进行比较。这项随机临床试验包括 34 名入住神经重症监护病房的严重创伤性脑损伤患者。大脑中动脉血流速度 (MCAv)、无创平均动脉压、心率和 PaCO ₂被记录；dCA 通过无创平均流量指数 (nMxa) 测量。在所有时间点，从仰卧位过渡到平视倾斜触发 MCAv 降低 10-16% 并增加 nMxa（P  < 0.05），组间没有差异。分别在基线、2 周和 4 周时直立不耐受的发作次数（5 对 3；1 对 2；1 对 0）没有差异，并且 PaCO ₂调整后的 nMxa变化与发生率之间没有关联直立反应 ( P = 0.35）。早期的直立性运动不影响动态大脑自动调节，也不能防止严重创伤性脑损伤患者的直立不耐受。试验注册：ClinicalTrials.gov 标识符：NCT02924649。2016 年 10 月 3 日注册。