动脉瘤性蛛网膜下腔出血病人Lindegaard比值与脑组织氧分压的相关性

目的 探讨动脉瘤性蛛网膜下腔出血（aSAH）病人经颅多普勒超声（TCD）检测Lindegaard比值（LR）与脑组织氧分压（PbtO2）的相关性。方法 2019年8月至2022年2月前瞻性收集aSAH共46例。使用LICOX-Ⅱ型脑组织氧分压监测系统，采用氧分压探针（Clark型微型电极）记录大脑中动脉供血脑组织PbtO2，其中PbtO2<20 mmHg且持续时间≥10 min定义为局部组织缺氧。TCD检测PbtO2探针同侧MCA和颈内动脉（ICA）颅外段，LR指同侧MCA与ICA颅外段平均血流速度比值，LR≥3存在脑血管痉挛。结果 根据PbtO2监测结果，16例出现脑组织缺氧（缺氧组），30例无脑组织缺氧（非缺氧组）；与非缺氧组相比，缺氧组入院GCS评分较低（P=0.041），脑血管痉挛发生率呈增高趋势（P=0.057）。LR判断存在脑血管痉挛37例，无脑血管痉挛9例。LR与PbtO2呈显著负相关（r=-0.305，P=0.039）。LR≥3预测脑组织缺氧的特异性很高（93.3%），但敏感性较低（56.3%）；LR对脑组织缺氧的阳性预测值和阴性预测值分别为81.8%和80.0%。结论 aSAH病人在预防性迟发性脑缺血监测时，TCD检测LR是预测脑组织缺氧较好的非侵入性方法，但其敏感性低，不能单纯通过LR结果正常而排除发生迟发性脑缺血的可能。

Relationship between Lindegaard ratio and brain tissue oxygen tension in patients with aneurysmal subarachnoid hemorrhage

Objective To investigate the relationship between Lindegaard ratio (LR) and brain tissue oxygen tension (PbtO2) in the patients with aneurysmal subarachnoid hemorrhage (aSAH). Methods Forty-six patients with aSAH were prospectively recruited between August 2019 and February 2022. The PbtO2 were recorded using Clark type oxygen microelectrodes in the cerebral tissues supplied by the middle cerebral artery (MCA), and local cerebral hypoxia was defined as PbtO2<20 mmHg and duration ≥10 min. The ipsilateral MCA and the extracranial segment of the internal carotid artery (ICA) with the PbtO2 probe were detected by transcranial Doppler ultrasound (TCD), and LR was the ratio of the mean velocity between the ipsilateral MCA and the extracranial segment of the ICA. Cerebral vasospasm was defined as LR ≥3. Results According to the monitoring results of PbtO2, local cerebral hypoxia occurred in 16 patients (hypoxia group), and did not in 30 (non-hypoxia group). Compared with the non-hypoxia group, the GCS score on admission significantly decreased in the hypoxia group (P=0.041), and the incidence of cerebral vasospasm increased in the hypoxia group (P=0.057). According to the LR results, cerebral vasospasm occurred in 37 patients and did not in 9. LR was significantly negatively correlated with PbtO2 (r=-0.305, P=0.039). The specificity and sensitivity of LR ≥3 in predicting cerebral hypoxia were 93.3% and 56.3%, respectively. The positive and negative predictive values of LR ≥3 in predicting cerebral hypoxia were 81.8% and 80.0%, respectively. Conclusions LR detection using TCD is a good non-invasive method to assess cerebral hypoxia in the patients with aSAH, but its sensitivity is low, and delayed cerebral ischemia cannot be excluded simply by normal LR results.