Department of Gastroenterology and Hepatology, St George's Hospital, London, UK.
Liver Int. 2010 Mar;30(3):463-71. doi: 10.1111/j.1478-3231.2009.02157.x. Epub 2009 Nov 16.
The circulatory dysfunction associated with cirrhosis is well described. Reduced systemic vascular resistance and high cardiac output are the main features of the hyperdynamic state, but involvement of the peripheral microcirculation in this process is poorly understood. Near infrared spectroscopy (NIRS) has been used to assess muscle tissue oxygenation (StO(2)) in haemorrhagic and septic shock. Vascular occlusion testing (VOT) can produce dynamic changes in StO(2) which represent tissue oxygen extraction, delivery, and hence, surrogate markers of microvascular function.
We aimed to investigate dynamic StO(2) changes in the peripheral microcirculation of patients with cirrhosis.
Thirty-five subjects were examined (25 cirrhosis, 10 healthy volunteers) with an InSpectra 650 StO(2) monitor and 15 mm thenar probe. Brachial VOT was applied at systolic blood pressure +50 mmHg for 3 min, in triplicate. Dynamic StO(2) parameters are reported for baseline, downslope, upslope, area over ischaemic curve, overshoot, area under recovery curve and recovery time.
Patients with cirrhosis demonstrated significantly larger post-occlusive hyperaemic variables compared with volunteers: overshoot (17 vs 15%, P=0.009), area under recovery curve (25.1 vs 16.3 %/min, P<0.001) and recovery time (3.0 vs 2.2 min, P<0.001). Magnitude of change was also seen to increase with disease stage as defined by Child-Pugh score. Serial VOT revealed microcirculatory ischaemic adaptation in volunteers, which was absent in cirrhosis.
NIRS can identify dynamic changes in muscle tissue oxygenation in cirrhosis which are compatible with microcirculatory vasodilatation. Ischaemic adaptation was seen in controls but not in patients with cirrhosis. NIRS techniques offer a novel approach to the assessment of peripheral vascular dysfunction in cirrhosis.
肝硬化相关的循环功能障碍已有详细描述。全身血管阻力降低和心输出量增加是高动力状态的主要特征，但外周微循环在此过程中的参与情况了解甚少。近红外光谱（NIRS）已用于评估失血性和感染性休克患者的肌肉组织氧合（StO₂）。血管闭塞试验（VOT）可使 StO₂产生动态变化，代表组织氧摄取、输送，因此是微血管功能的替代标志物。
我们旨在研究肝硬化患者外周微循环的动态 StO₂变化。
使用 InSpectra 650 StO₂监测仪和 15mm 大鱼际探头检查了 35 名受试者（25 名肝硬化患者，10 名健康志愿者）。在收缩压+50mmHg 下对肱动脉进行 3 分钟的 VOT，重复 3 次。报告基线、下坡、上坡、缺血曲线下面积、超射、恢复曲线下面积和恢复时间的动态 StO₂参数。
与志愿者相比，肝硬化患者的闭塞后充血变量明显更大：超射（17% vs 15%，P=0.009）、恢复曲线下面积（25.1% vs 16.3%/min，P<0.001）和恢复时间（3.0 分钟 vs 2.2 分钟，P<0.001）。根据 Child-Pugh 评分定义的疾病阶段，变化幅度也有所增加。志愿者的 VOT 呈系列变化，提示存在微循环缺血适应，而肝硬化患者则没有。
NIRS 可识别肝硬化患者肌肉组织氧合的动态变化，与微循环血管扩张一致。在对照组中观察到缺血适应，但在肝硬化患者中未观察到。NIRS 技术为评估肝硬化患者的外周血管功能障碍提供了一种新方法。
