Acute decrease in renal microvascular Po2 during acute normovolemic hemodilution
Acute decrease in renal microvascular Po2 during acute normovolemic hemodilution
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DOI：
10.1152/ajprenal.00206.2006
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发表时间：
2007-02-01
影响因子：
4.2
通讯作者：
Ince, Can
中科院分区：
文献类型：
--
作者：
Johannes, Tanja;Mik, Egbert G.;Ince, Can
器官系统对氧供应减少（如血液稀释）的耐受性存在很大差异。肾脏接收的是心输出量的25%，在正常情况下，O（2）的输送超过了氧需求。在大鼠急性等容血液稀释（ANH）模型中，我们研究了降低红细胞压积对肾脏局部和微血管氧合的影响。实验在12只麻醉雄性Wistar大鼠中进行。六只动物经历了四个阶段的ANH（红细胞压积25、15、10和< 10%）。6只动物作为时间匹配对照。监测全身和肾脏血流动力学和氧合参数。通过氧依赖性磷光猝灭法连续测定肾皮质（c）和外髓质（m）微血管PO（2）（μ PO 2）和肾静脉PO（2）（P（rv）O（2））。尽管在ANH的前两个步骤中肾血流量显著增加，但c μ PO（2）和m μ PO（2）立即下降。从第一步开始，耗氧量（VO（2）ren）依赖于氧输送量（DO（2ren））。随着红细胞压积的逐渐降低，可以观察到mu P（O2）和VO（2ren）之间的显著相关性，以及mu PO（2）和PrvO（2）之间的PO（2）间隙。此外，VO（2ren）和RBF之间有很高的相关性在很宽的流量范围。总之，在ANH的早期阶段，由于VO（2ren）增加、DO（2ren）减少和肾内O（2）分流的组合，肾组织的氧供应已经变得至关重要。这具有临床相关性，因为最近的出版物报告称，手术期间血液稀释是术后肾功能不全的风险因素。
Large differences in the tolerance of organ systems to conditions of decreased O(2) delivery such as hemodilution exist. The kidney receives similar to 25% of the cardiac output and O(2) delivery is in excess of the oxygen demand under normal circumstances. In a rat model of acute normovolemic hemodilution (ANH), we studied the effect of reduced hematocrit on renal regional and microvascular oxygenation. Experiments were performed in 12 anesthetized male Wistar rats. Six animals underwent four steps of ANH ( hematocrit 25, 15, 10, and < 10%). Six animals served as time-matched controls. Systemic and renal hemodynamic and oxygenation parameters were monitored. Renal cortical (c) and outer medullary ( m) microvascular PO(2) ( mu PO2) and the renal venous PO(2) (P(rv)O(2)) were continuously measured by oxygen-dependent quenching of phosphorescence. Despite a significant increase in renal blood flow in the first two steps of ANH, c mu PO(2) and m mu PO(2) dropped immediately. From the first step onward oxygen consumption (VO(2)ren) became dependent on oxygen delivery (DO(2ren)). With a progressive decrease in hematocrit, a significant correlation between mu P(O2) and VO(2ren) could be observed, as well as a PO(2) gap between mu PO(2) and PrvO(2). Furthermore, there was a high correlation between VO(2ren) and RBF over a wide range of flows. In conclusion, the oxygen supply to the renal tissue is becoming critical already in an early stage of ANH due to the combination of increased VO(2ren), decreased DO(2ren), and intrarenal O(2) shunt. This has clinical relevance as recent publications reporting that hemodilution during surgery forms a risk factor for postoperative renal dysfunction.