Experimental approach for clinical use of NIRS as a monitor of hepatic oxygenation

在这项研究中，我们评估了是否可能应用近红外光谱（NIRS）来监测肝氧合。此外，我们还评估了近红外光谱入路的可行性。（方法）采用多普勒血流仪测定肝血流。ⅰ组将近红外探头置于肝表面，ⅱ组将恍惚-食管入路专用探头置入胃内。脱氧血红蛋白和脱氧血红蛋白，以及细胞色素氧化酶(cyt。采用4种波长算法计算肝脏的Ox .)。（结果与讨论）ⅰ组(1)急性出血时氧血红蛋白与ShvO_2呈正相关（r = 0.97, p < 0.01）；(2)输注去甲肾上腺素时，肝总血流量和总Hb（氧-Hb +脱氧-Hb）均显著降低，细胞计数明显下降。x被还原了。(3)充血时，氧合血红蛋白和脱氧血红蛋白升高，细胞活力升高。x被还原了。(4)在内毒素输注过程中，肝血流有三种动态变化。Oxy-Hb和deoxy-Hb在II期和III期升高，而cyt。III期减少。从这些数据中，我们得出结论，局部肝氧合是由细胞氧化还原状态正确监测的。牛. .II组，(1)将放置在胃和肝脏之间的黑布取下后，插入胃内的探针测得的光密度发生明显变化。(2)门静脉闭塞时，cyt。x被还原了。这些数据表明，近红外光可以很容易地穿透胃壁，并且可以通过近红外光出神-食管入路通过胃监测肝氧合。

In this study, we evaluated whether it was possible to apply the near infrared spectroscopy (NIRS) to monitor the hepatic oxygenation. Furthermore, it was assessed the possibility of trance-esophageal approach of NIRS.(METHODS) The hepatic blood flow was measured by Doppler flowmetry. The probes of NIRS were placed on the liver surface in-group I, and the special probe for trance-esophageal approach was inserted into the stomach in-group II.Oxy-Hb and deoxy-Hb, and cytochrome oxidase (cyt. ox.) in the liver were calculated using 4 wavelength algorithms. (RESULTS AND DISCUSSION) In group I, (1) there was a positive correlation (r = 0.97, p < 0.01) between oxy-Hb and ShvO_2 during acute hemorrhage. (2) during infusion of noradrenarine, total hepatic blood flow and total Hb (oxy-Hb + deoxy-Hb) were significantly decreased, and cyt. ox. was reduced. (3) during congestion, oxy-Hb and deoxy-Hb were increased and cyt. ox. was reduced. (4) during infusion of endotoxin, there were three dynamic changes of hepatic blood flow. Oxy-Hb and deoxy-Hb were increased in stage II and III, while cyt. ox. was reduced in stage III.From these data, we concluded that the regional hepatic oxygenation was correctly monitored by the redox state of cyt. ox.. In-group II, (1) when the black sheet placed between stomach and liver was removed, the optical density measured by the probe inserted into stomach was significantly changed. (2) During occlusion of portal vein, cyt. ox. was reduced. From these data, it was suggested that NIR light is possible to penetrate easily the wall of stomach, and the hepatic oxygenation may be monitored via stomach by the trance-esophageal approach of NIRS.