Eleveld Nick, Hoedemaekers Cornelia W E, van Kaam C Ruud, Leijte Guus P, van den Brule Judith M D, Pickkers Peter, Aries Marcel J H, Maurits Natasha M, Elting Jan Willem J
Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.
Department of Intensive Care Medicine, Radboud University Medical Center, Radboud University, Nijmegen, Netherlands.
Front Neurol. 2021 Sep 10;12:695705. doi: 10.3389/fneur.2021.695705. eCollection 2021.
Cerebral perfusion may be altered in sepsis patients. However, there are conflicting findings on cerebral autoregulation (CA) in healthy participants undergoing the experimental endotoxemia protocol, a proxy for systemic inflammation in sepsis. In the current study, a newly developed near-infrared spectroscopy (NIRS)-based CA index is investigated in an endotoxemia study population, together with an index of focal cerebral oxygenation. Continuous-wave NIRS data were obtained from 11 healthy participants receiving a continuous infusion of bacterial endotoxin for 3 h (ClinicalTrials.gov NCT02922673) under extensive physiological monitoring. Oxygenated-deoxygenated hemoglobin phase differences in the (very)low frequency (VLF/LF) bands and the Tissue Saturation Index (TSI) were calculated at baseline, during systemic inflammation, and at the end of the experiment 7 h after the initiation of endotoxin administration. The median (inter-quartile range) LF phase difference was 16.2° (3.0-52.6°) at baseline and decreased to 3.9° (2.0-8.8°) at systemic inflammation ( = 0.03). The LF phase difference increased from systemic inflammation to 27.6° (12.7-67.5°) at the end of the experiment ( = 0.005). No significant changes in VLF phase difference were observed. The TSI (mean ± SD) increased from 63.7 ± 3.4% at baseline to 66.5 ± 2.8% during systemic inflammation ( = 0.03) and remained higher at the end of the experiment (67.1 ± 4.2%, = 0.04). Further analysis did not reveal a major influence of changes in several covariates such as blood pressure, heart rate, PaCO, and temperature, although some degree of interaction could not be excluded. A reversible decrease in NIRS-derived cerebral autoregulation phase difference was seen after endotoxin infusion, with a small, sustained increase in TSI. These findings suggest that endotoxin administration in healthy participants reversibly impairs CA, accompanied by sustained microvascular vasodilation.
脓毒症患者的脑灌注可能会发生改变。然而，在接受实验性内毒素血症方案（脓毒症全身炎症的替代模型）的健康参与者中，关于脑自动调节（CA）的研究结果存在矛盾。在当前研究中，我们在内毒素血症研究人群中研究了一种新开发的基于近红外光谱（NIRS）的CA指数以及局灶性脑氧合指数。在广泛的生理监测下，从11名接受连续3小时细菌内毒素输注的健康参与者（ClinicalTrials.gov NCT02922673）获取连续波NIRS数据。在基线、全身炎症期间以及内毒素给药开始后7小时实验结束时，计算（极）低频（VLF/LF）波段的氧合血红蛋白与脱氧血红蛋白相位差以及组织饱和度指数（TSI）。基线时，LF相位差的中位数（四分位间距）为16.2°（3.0 - 52.6°），在全身炎症时降至3.9°（2.0 - 8.8°）（P = 0.03）。实验结束时，LF相位差从全身炎症时升高至27.6°（12.7 - 67.5°）（P = 0.005）。未观察到VLF相位差有显著变化。TSI（均值±标准差）从基线时的63.7 ± 3.4%升高至全身炎症期间的66.5 ± 2.8%（P = 0.03），并在实验结束时保持较高水平（67.1 ± 4.2%，P = 0.04）。进一步分析未发现血压、心率、动脉血二氧化碳分压和体温等多个协变量变化的主要影响，尽管不能排除一定程度的相互作用。内毒素输注后，NIRS衍生的脑自动调节相位差出现可逆性降低，同时TSI有小幅持续升高。这些发现表明，健康参与者接受内毒素给药会可逆性损害CA，并伴有微血管持续扩张。
