急性高容量血液稀释对血液动力学及血液流变学的影响

目的探讨不同速率输注6%羟乙基淀粉(HES)进行急性高容量血液稀释(AHH)对血液动力学及血液流变学的影响.方法20例ASAⅠ级的吸入全麻患者分为2组,每组10例.输注速率Ⅰ组10ml@kg@h-1,Ⅱ组20ml@kg-1@h-1.监测Ⅱ导联ECG、HR、SP、MAP、DP、CO、CI、CVP、PAP、PCWP、SpO2、PETCO2以及N2O和异氟醚呼末浓度,并行动脉血气分析和血液流变学检查.结果输注HES30和60min时,Ⅱ组HR降幅与Ⅰ组降幅比较无显著性差异(P＞0.05).Ⅰ组和Ⅱ组CI增幅基本相同(P＞0.05).60min时Ⅰ组动脉血压稍有升高,而Ⅱ组呈下降趋势(P＜0.05).输注期间2组CVP、PAP和PCWP均明显升高,60min时的升幅比30min时更大(P＜0.05);Hct、血沉方程K值和Hb浓度均明显下降,60min时降幅比30min时更大(P＜0.05).结论增加HES输注量,提高输注速率能有效加快血液扩容、稀释,但血液动力学受影响程度将加重.手术期间有血容量下降的情况下,以20ml@kg-1@h-1速率输注HES是安全的.

Hemodynamic and hemorheological effects of hypovolemic hemodilution with hydroxyethyl starch

Objective To investigate the hemodynamic and rheological effects of acute hypovolemic hemodilution with 6% hydroxyethyl starch (HES) at different infusion rates. Methods 20 ASA Ⅰ adult patients undergoing elective surgery were randomized to one of two groups with 10 patients each. The patients were premedicated with intramuscular midazolam 0.06 mg/kg and atropine 0.01 mg/kg 30 min before anesthesia. Before anesthesia an intravenous line was established and lacted ringer solution was infused at a rate of 5 ml. kg-1. h-1 . Anesthesia was induced with midazolam 0.2mg/kg , fentanyl 5μg/kg and vecuronium 0. lmg/kg and maintained with inhalation of 50 % N2O and 1% isoflurane. After tracheal intubation the patients were mechanically ventilated and PET CO2 was maintainted between 4.6-6.0 kPa.Swan-Ganz catheter was inserted via right internal jugular vein. The dorsalis pedis artery was cannulated for direct measurement of arterial pressure. 6% HES infusion rates were 10 ml.kg-1.h-1 in group Ⅰ and 20ml.kg-1 .h-1 in group Ⅱ respectively. ECG, heart rate (HR), arterial blood pressure (SBP, DBP and MAP), CO, CL, CVP, PAP, PCWP, SpO2, PET CO2 and inhalation concentrations of N2O and isoflurane were monitored before and 30, and 60 min after infusion was started. Arterial and venous blood samples were taken for blood gas analysis and rheological studies. Results The two groups were comparable with respect to demographic data. During HES infusion HR decreased and CL increased in both groups and there was no significant difference between the two groups. BP increased slightly at 60 min in group Ⅰ , whereas in group Ⅱ it tended to decrease. CVP, PAP and PCWP increased significantly in both groups especially at 60 min. Hct decreased from 36.2% ±4.5% to 30.4% ±4.1% in group Ⅰ and from 39.6%±8.0 % to 30.8% ± 5.9 % in group Ⅱ at 60 min. Hb and K value of erythrocyte sedimentation rate (ESR) equation decreased significantly in both groups especially at 60 min. Conclusions Intravascular volume expansion ismore efficient with increased infusion rate of HES but the influences on hemodynamics would be more significant. HES infused at 20 ml. kg-1 . h -1 is safe in healthy patient during operation with blood loss.[Key Words] Hemodilution; Hydroxyethyl starch; Hemodynamics; Hemorheology