急性超容性血液稀释对机体循环的影响

Effects of acute hypervolemic hemodilution on circulation

目的：观察急性超容性血液稀释（AHHD）对机体循环的影响和扩容率的变化，评价AHHD的安全性和有效性。方法：临床选择14例择期行耳鼻喉科和颌面外科手术患者。ASAⅠ～Ⅱ级，全麻诱导和气管插管后20～30min内以林格氏注射液10ml／kg和6％羟乙基淀粉溶液按公式[输注量=估计血容量×（初始Hct-稀释后Hct）／稀释后Hct]进行AHHD。于AHHD前、AHHD完成、AHHD后40min记录心率（HR）、平均动脉压（MAP）和中心静脉压（CVP），并计算CVP升幅和扩容率。结果：（1）CVP在AHHD完成即刻显著升高（P〈0．05），但AHHD后40min又恢复至AHHD前水平。HR及MAP在AHHD完成即刻无显著变化，但于AHHD后40min有所升高（P〈0．05）。（2）红细胞压积（Hct）、血红蛋白（Hb）在AHHD完成后显著下降：Hct为（25．85±2．51）％、Hb为（8．78±0．87）g／L（P〈0．05）．扩容率为（20±6．6）％。（3）CVP升幅为（0．73±0．78）cmH2O，与扩容率相关性较差（r=0．504）。结论：应用公式估计扩容量输注血浆代用品行AHHD是安全有效的，可以维持机体循环的稳定；CVP的升高不能完全反映血容量的变化。不能作为判断前负荷的唯一指标。

Objextive： To investigate the effects of acute hypervolemic hemodilution （AHHD） on circulation and to evaluate the correlation of the changes in CVP and hemodilution rate. Methods： Fourteen ASA Ⅰ-Ⅱ patients （6 male, 8 female） undergoing selective orthopedic surgery were entered in this study. After induction of anesthesia the patients received 10 ml/kg Ringer＇s solution and 6% HES [predicted volume of infusion： predicted blood volume × （ Hctbefore AHHD- Hctafter AHHD）/Hctafter AHHD] within 20 - 30 min. The heart rate （HR）, mean arterial blood pressure （MAP） and central vein pressure （CVP） were continuousely monitored and recorded before AHHD,after AHHD and 40 minutes later. The changes of CVP and hemodilution rate were calculated [hemodilution rate ： （ Hctbefore AHHD-hct after AHHD）/Hctbefore AHHD]. Results ： （1） After AHHD the CVP increased （P≤0.05）,but 40 minutes later it returned to the beginning. The HR and MAP increased after AHHD 40 minutes later （P≤0.05）. （2） Hct, Hb decreased （P≤0.05）significantly after AHHD. The hemodilution rate was （20±6.6） % . （3） There was no relationship between the changes in CVP and hemodilution rate. The correlation ratio was 0. 504. Conclusion： AHHD with the formula [predicted volume of infusion = predicted blood volume × （ Hctbefore AHHD-hct after AHHD）/Hctbefore AHHD] was effective and safe in terms of hemodynamic changes. The changes in CVP could only partly reflect the changes in the circulatory volume. CVP was not the only factor to determine preload.