Chatpun Surapong, Cabrales Pedro
Department of Bioengineering, University of California-San Diego, La Jolla, CA 92093, USA.
Biorheology. 2010;47(3-4):225-37. doi: 10.3233/BIR-2010-0574.
The purpose of this study was to investigate how plasma viscosity affects cardiac and vascular function during moderate hemodilution. Twelve anesthetized hamsters were hemodiluted by 40% of blood volume with two different viscosity plasma expanders. Experimental groups were based on the plasma expander viscosity, namely: high viscosity plasma expander (HVPE, 6.3 mPa · s) and low viscosity plasma expander (LVPE, 2.2 mPa · s). Left ventricular (LV) function was intracardiacally measured with a high temporal resolution miniaturized conductance catheter and concurrent pressure-volume results were used to calculate different LV indices. Independently of the plasma expander, hemodilution decreased hematocrit to 28% in both groups. LVPE hemodilution reduced whole blood viscosity by 40% without changing plasma viscosity, while HVPE hemodilution reduced whole blood viscosity by 23% and almost doubled plasma viscosity relative to baseline. High viscosity plasma expander hemodilution significantly increased cardiac output, stroke volume and stroke work compared to baseline, whereas LVPE hemodilution did not. Furthermore, an increase in plasma viscosity during moderate hemodilution produced a higher energy transfer per unit volume of ejected blood. Systemic vascular resistance decreased after hemodilution in both groups. Counter-intuitively, HVPE hemodilution showed lower vascular resistance and vascular hindrance than LVPE hemodilution. This result suggests that geometrical changes in the circulatory system are induced by the increase in plasma viscosity. In conclusion, an increase in plasma viscosity after moderate hemodilution directly influenced cardiac and vascular function by maintaining hydraulic power and reducing systemic vascular resistance through vasodilation.
本研究的目的是调查在中度血液稀释过程中血浆粘度如何影响心脏和血管功能。用两种不同粘度的血浆扩容剂将12只麻醉的仓鼠的血容量稀释40%。实验组基于血浆扩容剂的粘度，即：高粘度血浆扩容剂（HVPE，6.3 mPa·s）和低粘度血浆扩容剂（LVPE，2.2 mPa·s）。使用高时间分辨率的小型化电导导管心内测量左心室（LV）功能，并使用同步压力-容积结果计算不同的左心室指标。与血浆扩容剂无关，两组血液稀释均使血细胞比容降至28%。LVPE血液稀释使全血粘度降低40%，而血浆粘度不变，而HVPE血液稀释使全血粘度降低23%，且血浆粘度相对于基线几乎增加了一倍。与基线相比，高粘度血浆扩容剂血液稀释显著增加了心输出量、每搏输出量和每搏功，而LVPE血液稀释则没有。此外，中度血液稀释过程中血浆粘度的增加导致每单位射出血量的能量传递更高。两组血液稀释后全身血管阻力均降低。与直觉相反，HVPE血液稀释显示出比LVPE血液稀释更低的血管阻力和血管阻力。这一结果表明，血浆粘度的增加会引起循环系统的几何形状变化。总之，中度血液稀释后血浆粘度的增加通过维持水力功率和通过血管舒张降低全身血管阻力，直接影响心脏和血管功能。
