The Burden of Brain Hypoxia and Optimal Mean Arterial Pressure in Patients With Hypoxic Ischemic Brain Injury After Cardiac Arrest
The Burden of Brain Hypoxia and Optimal Mean Arterial Pressure in Patients With Hypoxic Ischemic Brain Injury After Cardiac Arrest
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DOI：
10.1097/ccm.0000000000003745
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发表时间：
2019-07-01
影响因子：
8.8
通讯作者：
Griesdale, Donald E. G.
中科院分区：
文献类型：
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作者：
Sekhon, Mypinder S.;Gooderham, Peter;Griesdale, Donald E. G.
目的：在心脏骤停后存在缺氧缺血性脑损伤风险的患者中，我们试图：1)表征脑氧合并确定脑缺氧的患病率；2)利用压力反应性指数表征自身调节并确定最佳平均动脉压；3)评估最佳平均动脉压与脑组织氧合之间的关系。设计：前瞻性介入研究。单位：第四系ICU。患者：心脏骤停72小时内，自发循环恢复时间大于10分钟，复苏后格拉斯哥昏迷评分低于9分的成年患者。干预措施：所有患者均接受多模式神经监测，包括：1)脑组织氧合，2)颅内压，3)颈静脉连续血氧测定，4)近红外光谱区域血氧饱和度，5)基于压力反应性指数确定最佳平均动脉压，自动调节下限和上限。我们还收集了平均动脉压、潮末二氧化碳和温度。所有数据均使用ICM+ (Cambridge Enterprise, Cambridge, uk)脑监测软件在300 Hz下采集。测量和主要结果：纳入10例患者（7名男性），中位年龄47岁（范围20-71岁），恢复自然循环22分钟（12-36分钟）。中位监测时间为47小时（15-88小时），从心脏骤停到纳入的中位持续时间为15小时（6-44小时）。脑组织氧合平均为23 mm Hg (sd为8 mm Hg)，脑组织氧合低于20 mm Hg的平均时间百分比为38%（6-100%）。平均压力反应性指数为0.23(0.27)，压力反应性指数大于0.3的时间占50%（12-91%）。平均最佳平均动脉压、自动调节下限和上限分别为89 mm Hg（11）、82 mm Hg(8)和96 mm Hg(9)。平均动脉压与脑氧合指数之间的关系在患者之间存在明显的差异。当患者实际平均动脉压接近最佳平均动脉压时，脑组织氧合增加（p < 0.001）。当实际平均动脉压高于最佳平均动脉压时，这种正相关关系不存在。结论：缺氧缺血性脑损伤的脑缺氧发作是频繁的，在最佳平均动脉压附近的灌注与脑组织氧合增加有关。压力反应性指数可以得出心脏骤停患者的最佳平均动脉压、自动调节的下限和上限。
Objectives: In patients at risk of hypoxic ischemic brain injury following cardiac arrest, we sought to: 1) characterize brain oxygenation and determine the prevalence of brain hypoxia, 2) characterize autoregulation using the pressure reactivity index and identify the optimal mean arterial pressure, and 3) assess the relationship between optimal mean arterial pressure and brain tissue oxygenation. Design: Prospective interventional study. Setting: Quaternary ICU. Patients: Adult patients with return of spontaneous circulation greater than 10 minutes and a postresuscitation Glasgow Coma Scale score under 9 within 72 hours of cardiac arrest. Interventions: All patients underwent multimodal neuromonitoring which included: 1) brain tissue oxygenation, 2) intracranial pressure, 3) jugular venous continuous oximetry, 4) regional saturation of oxygen using near-infrared spectroscopy, and 5) pressure reactivity index-based determination of optimal mean arterial pressure, lower and upper limit of autoregulation. We additionally collected mean arterial pressure, end-tidal CO2, and temperature. All data were captured at 300 Hz using ICM+ (Cambridge Enterprise, Cambridge, United Kingdom) brain monitoring software. Measurements and Main Results: Ten patients (7 males) were included with a median age 47 (range 20-71) and return to spontaneous circulation 22 minutes (12-36 min). The median duration of monitoring was 47 hours (15-88 hr), and median duration from cardiac arrest to inclusion was 15 hours (6-44 hr). The mean brain tissue oxygenation was 23 mm Hg (sd 8 mm Hg), and the mean percentage of time with a brain tissue oxygenation below 20 mm Hg was 38% (6-100%). The mean pressure reactivity index was 0.23 (0.27), and the percentage of time with a pressure reactivity index greater than 0.3 was 50% (12-91%). The mean optimal mean arterial pressure, lower and upper of autoregulation were 89 mm Hg (11), 82 mm Hg (8), and 96 mm Hg (9), respectively. There was marked between-patient variability in the relationship between mean arterial pressure and indices of brain oxygenation. As the patients' actual mean arterial pressure approached optimal mean arterial pressure, brain tissue oxygenation increased (p < 0.001). This positive relationship did not persist when the actual mean arterial pressure was above optimal mean arterial pressure. Conclusions: Episodes of brain hypoxia in hypoxic ischemic brain injury are frequent, and perfusion within proximity of optimal mean arterial pressure is associated with increased brain tissue oxygenation. Pressure reactivity index can yield optimal mean arterial pressure, lower and upper limit of autoregulation in patients following cardiac arrest.