BACKGROUND An association between spontaneous hyperventilation, delayed cerebral ischemia, and poor clinical outcomes has been reported in subarachnoid hemorrhage. We evaluated the relationship between early pCO2 changes, ischemic lesions and outcomes in patients with intracerebral hemorrhage (ICH). METHODS Consecutive patients with spontaneous ICH were enrolled in an observational cohort study conducted between 2006 and 2019. Patient characteristics and discharge outcome were prospectively recorded. Arterial blood gas (ABG) measurements and mechanical ventilation settings in the first 72 h of admission were retrospectively collected. MRI images were adjudicated for diffusion-restricted lesions consistent with ischemia and distant from the hematoma. We examined the associations between pCO2 changes, ischemic lesions, and discharge outcomes by univariate and adjusted analyses. RESULTS ABG data were available for 220 patients. Hyperventilation occurred in 52 (28%) cases and was not associated with clinical severity. Lower initial pCO2 was associated with greater risk of in-hospital death (OR 0.94 per mmHg, 95%CI [0.89, 0.996], p = 0.042) after adjustment for ICH Score, pneumonia and mechanical ventilation requirements. MRI data were available for 33 patients. Lower pCO2 was associated with a higher risk of ischemic lesions, except in patients with low initial systolic blood pressure (p < 0.05 for main and blood pressure interaction effects), after adjustment for other predictors. CONCLUSIONS In ICH patients with spontaneous ventilation, lower pCO2 was independently associated with greater risk of in-hospital death. In patients with elevated initial blood pressure, who undergo blood pressure reduction per guideline recommendations, lower pCO2 was associated with increased risk to develop ischemic lesions.

中文翻译：

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脑出血后低碳酸血症、缺血性病变和结果

背景已报道蛛网膜下腔出血与自发过度换气、迟发性脑缺血和不良临床结果之间存在关联。我们评估了早期 pCO2 变化、缺血性病变和脑出血 (ICH) 患者预后之间的关系。方法 在 2006 年至 2019 年间进行的一项观察性队列研究中，连续招募了自发性 ICH 患者。前瞻性地记录了患者特征和出院结果。回顾性收集入院前 72 小时的动脉血气 (ABG) 测量值和机械通气设置。MRI 图像被判定为与缺血一致且远离血肿的弥散受限病变。我们检查了 pCO2 变化、缺血性病变、通过单变量和调整分析得出出院结果。结果 可获得 220 名患者的 ABG 数据。52 例 (28%) 发生过度换气，且与临床严重程度无关。在调整 ICH 评分、肺炎和机械通气要求后，较低的初始 pCO2 与较高的院内死亡风险相关（OR 0.94/mmHg，95%CI [0.89, 0.996]，p = 0.042）。可获得 33 名患者的 MRI 数据。在调整其他预测因素后，较低的 pCO2 与较高的缺血性病变风险相关，但初始收缩压较低的患者除外（主要和血压相互作用的影响 p < 0.05）。结论 在自主通气的 ICH 患者中，较低的 pCO2 与较高的院内死亡风险独立相关。