Systemic microvascular shunting through hyperdynamic capillaries after acute physiological disturbances following cardiopulmonary bypass
Systemic microvascular shunting through hyperdynamic capillaries after acute physiological disturbances following cardiopulmonary bypass
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DOI：
10.1152/ajpheart.00397.2014
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发表时间：
2014-10-01
影响因子：
4.8
通讯作者：
Boer, Christa
中科院分区：
文献类型：
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作者：
Koning, Nick J.;Simon, Lotte E.;Boer, Christa
以前我们发现，心脏手术期间的心肺转流（CPB）与舌下微循环灌注和氧合减少有关。有研究表明，微循环灌注受损可能是由于微血管床中流动的异质性增加而导致的，可能导致动静脉分流。在这里，我们调查了我们的假设，急性血液动力学紊乱在体外循环确实导致微循环异质性与高动力毛细血管灌注和减少全身氧提取。在这项单中心前瞻性观察性研究中，纳入了接受心脏手术（n = 18）或不接受CPB（n = 13）的患者。通过侧流暗视野成像评估围手术期舌下微循环灌注，并对微循环异质性和高动力毛细血管灌注进行定量记录。分析其与血流动力学及氧合参数的关系。微循环异质性指数在CPB开始后显著增加[0.5（0.0-0.9）至1.0（0.3-1.3）; P = 0.031]，但在非体外循环手术期间没有增加。仅CPB组术中毛细血管红细胞（RBC）速度中位数增加[1，600（913- 2，500 μ m/s）vs. 380（190-480 μ m/s）; P < 0.001]，31%的毛细血管支持高RBC速度（> 2，000 μ m/s）。高动力微循环灌注与体外循环期间和之后动静脉氧差和全身氧消耗的减少有关。目前的研究提供了第一个直接的人类证据，通过高动力毛细血管的微血管分流现象后，CPB发作后的急性生理紊乱。血液动静脉氧差降低和CPB相关的全身氧摄取降低支持了由高动力毛细血管引起的全身氧卸载受损的假设。
Previously we showed that cardiopulmonary bypass (CPB) during cardiac surgery is associated with reduced sublingual microcirculatory perfusion and oxygenation. It has been suggested that impaired microcirculatory perfusion may be paralleled by increased heterogeneity of flow in the microvascular bed, possibly leading to arteriovenous shunting. Here we investigated our hypothesis that acute hemodynamic disturbances during extracorporeal circulation indeed lead to microcirculatory heterogeneity with hyperdynamic capillary perfusion and reduced systemic oxygen extraction. In this single-center prospective observational study, patients undergoing cardiac surgery with (n = 18) or without (n = 13) CPB were included. Perioperative microcirculatory perfusion was assessed sublingually with sidestream darkfield imaging, and recordings were quantified for microcirculatory heterogeneity and hyperdynamic capillary perfusion. The relationship with hemodynamic and oxygenation parameters was analyzed. Microcirculatory heterogeneity index increased substantially after onset of CPB [0.5 (0.0-0.9) to 1.0 (0.3-1.3); P = 0.031] but not during off-pump surgery. Median capillary red blood cell (RBC) velocity increased intraoperatively in the CPB group only [1,600 (913-2,500 mu m/s) vs. 380 (190-480 mu m/s); P < 0.001], with 31% of capillaries supporting high RBC velocities (>2,000 mu m/s). Hyperdynamic microcirculatory perfusion was associated with reduced arteriovenous oxygen difference and systemic oxygen consumption during and after CPB. The current study provides the first direct human evidence for a microvascular shunting phenomenon through hyperdynamic capillaries following acute physiological disturbances after onset of CPB. The hypothesis of impaired systemic oxygen offloading caused by hyperdynamic capillaries was supported by reduced blood arteriovenous oxygen difference and low systemic oxygen extraction associated with CPB.