The 30° head position improves dynamic cerebral autoregulation in patients undergoing reperfusion therapy: A prospective self-controlled study

At present, the optimal head position for stroke patients undergoing reperfusion therapy remains unclear. Because different head positions may exert distinct effects on dynamic cerebral autoregulation (dCA). In this self-controlled study, the cerebral blood flow velocity (CBFV) in the middle cerebral artery and finger blood pressure at the 0° and 30° head positions was continuously recorded using transcranial Doppler combined with servo-controlled finger plethysmography at 24 h, 3 days, and 7 days after reperfusion. These data were then used to calculate the dCA parameters (phase difference [PD], gain, and coherence function) through transfer function analysis. Meanwhile, 30 healthy controls were included. Finally, 83 patients who underwent reperfusion therapy were included in the final analysis. For both sides, the phase difference in the 30° head position was significantly higher at 24 h (affected side: p = 0.047; unaffected side: p = 0.003), 3 days (affected side: p = 0.040, unaffected side: p = 0.016)), and 7 days (affected side: p < 0.001; unaffected side: p < 0.001) than that in the 0° head position. There was no significant difference in cerebral blood flow velocity between the 0° and 30° head positions on both affected and unaffected sides. Additionally, no difference of dCA and cerebral blood flow velocity was found in different head positions among healthy controls. The 30° head position for patients undergoing reperfusion therapy for acute ischemic stroke is beneficial for improving dCA.