Abstract:

Objective: To investigate sex difference of dynamic cerebral autoregulation (dCA) in different body positions. Methods: A total of 130 healthy adults (65 males and 65 females) who underwent physical examination in Xuanwu Hospital Capital Medical University from August 2021 to November 2022 were included. Non-invasive continuous blood pressure monitor and transcranial Doppler ultrasonography (TCD) were used to monitor beat-to-beat blood pressure and middle cerebral artery (MCA) cerebral blood flow velocity (CBFV), respectively. Transfer function analysis (TFA) was used to compare and analyze the dCA parameters (absolute gain value and percentage gain, phase, coherence) in the range of very low frequency (0.02-0.07 Hz), low frequency (0.07-0.20 Hz) and high frequency (0.20-0.50 Hz) of different positions and sex. Results: The phase in very low frequency and low frequency were significantly lower in the standing position than in the supine position[(57.37 ±12.45)° vs. (66.72 ±16.64)°, t=-6.428, P=0.000; (36.82 ±11.59)° vs. (43.02 ±11.51)°, t=-6.052, P=0.000], while the coherence in very low frequency and low frequency were significantly higher in the standing position than in the supine position (0.73 ±0.06 vs. 0.66 ±0.06, t=-8.947, P=0.000; 0.76 ±0.06 vs. 0.73 ±0.07, t=-2.693, P=0.007). In both supine and standing positions, absolute gain value of male in the low frequency[(0.91 ±0.23) cm/(s·mm Hg) vs. (1.04 ±0.23) cm/(s·mm Hg), t=3.075, P=0.003; (0.84 ±0.19) cm/(s·mm Hg) vs. (0.95 ±0.21) cm/(s·mm Hg), t=3.102, P=0.002] and high frequency[(0.94 ±0.25) cm/(s·mm Hg) vs. (1.11 ±0.27) cm/(s·mm Hg), t=3.740, P=0.000; (0.91 ±0.21) cm/(s·mm Hg) vs. (1.05 ±0.23) cm/(s·mm Hg), t=3.747, P=0.000] was lower than those of female, while the phase in the low frequency was higher than that of female[(45.25 ±10.21)° vs. (40.81 ±12.37)°, t=-2.239, P=0.027; (38.90 ±12.25)° vs. (34.74 ±10.57)°, t=-2.072, P=0.040]. Conclusions: Postural changes can also affect the cerebral autoregulation, and dCA can be improved in the supine position; there is no significant difference in dCA between male and female in the very low frequency, but there is a certain difference between the sex in the low frequency and high frequency.

Key words: Ultrasonography, Doppler, transcranial, Middle cerebral artery, Blood pressure, Hemodynamics, Posture, Gender identity

摘要：

目的: 探讨不同体位下动态脑血流自动调节（dCA）的性别差异。方法: 纳入2021年8月至2022年11月在首都医科大学宣武医院行体格检查的130名健康成人（男性65名和女性65名），应用无创连续血压测量仪和经颅多普勒超声检测无创逐波血压和大脑中动脉血流速度，传递函数分析法对比分析不同体位和性别在超低频（0.02~0.07 Hz）、低频（0.07~0.20 Hz）和高频（0.20~0.50 Hz）频域内的dCA参数（包括增益绝对值和百分比、相位差、一致性）。结果: 超低频和低频频域内直立位相位差均低于仰卧位[（57.37 ±12.45）°对（66.72 ±16.64）°，t=-6.428，P=0.000；（36.82 ±11.59）°对（43.02 ±11.51）°，t=-6.052，P=0.000]，一致性则高于仰卧位（0.73 ±0.06对0.66 ±0.06，t=-8.947，P=0.000；0.76 ±0.06对0.73 ±0.07，t=-2.693，P=0.007）。无论仰卧位还是直立位，男性在低频[（0.91 ±0.23）cm/（s·mm Hg）对（1.04 ±0.23）cm/（s·mm Hg），t=3.075，P=0.003；（0.84 ±0.19）cm/（s·mm Hg）对（0.95 ±0.21）cm/（s·mm Hg），t=3.102，P=0.002]和高频[（0.94 ±0.25）cm/（s·mm Hg）对（1.11 ±0.27）cm/（s·mm Hg），t=3.740，P=0.000；（0.91 ±0.21）cm/（s·mm Hg）对（1.05 ±0.23）cm/（s·mm Hg），t=3.747，P=0.000]频域内大脑中动脉增益绝对值均低于女性，低频频域内相位差高于女性[（45.25 ±10.21）°对（40.81 ±12.37）°，t=-2.239，P=0.027；（38.90 ±12.25）°对（34.74 ±10.57）°，t=-2.072，P=0.040]。结论: 体位变化可影响脑血流自动调节能力，仰卧位dCA得以改善；低频和高频频域内男性与女性dCA存在一定差异。

关键词: 超声检查，多普勒，经颅, 大脑中动脉, 血压, 血流动力学, 体位, 性别特征