高血容量血液稀释对老年患者围术期血流动力学的影响

Transesophageal Doppler monitoring of acute hypervolemic hemodilution tolerance in elderly patients without cardiac disease

目的:观察高血容量血液稀释(hypervolemic hemodilution,HHD)对老年患者围术期血流动力学的影响。方法:选取20名无心脏病史的麻醉手术患者;10名患者>65周岁,10名<55周岁。所有入试患者在术前接受相同的HHD处理(60 g/L羟乙基淀粉静脉输注,15 ml/kg)。在血液稀释后不同时间使用经食管多普勒超声监测(transesophageal Doppler monitoring,TDM)患者的血流动力学变化,同时监测患者血细胞比容(Hct)、血红蛋白、血气及心电变化。结果:所有患者手术期间均未发生任何并发症。两组患者间的一般资料、生化检查数据、Hct、血气等均无统计学差异。HHD后对照组(<55周岁)的心排出量(cardiac output,CO)升高,老年组(>65周岁)降低。对照组的心率(heart rate,HR)下降和心搏指数(stroke index,SI)升高(P<0.05),而老年组HR无明显改变,SI轻微下降。血液稀释后对照组患者的外周血管阻力值有明显下降(P<0.05),而老年患者出现了升高的趋势。结论:无心脏病史的老年患者并不能很好耐受术前急性高容量血液稀释。HHD可以导致由SI下降所致的CO下降。

AIM： To assess the influence of hypervolemic hemodilution （HHD） on hemodynamics in elderly patients without cardiac disease. METHODS： We examined 20 anesthetized patients without evidence of heart disease （10 patients 〉65 years and 10 patients 〈 55 years）. All patients underwent HHD hemodilution. Hematocrit （Hct）, hemoglobin, blood gas and ECG were also monitored during hemodilution. RESULTS： No complications occurred in the patients during surgery and no differences in biometric data, Hot, and blood gases were observed between groups. After HHD, cardiac output （CO） increased in the control group but decreased in the elderly patients （ I〉65 years）. The change of CO was solely the result of changes in stoke volume （SV） as the heart rate （HR） decreased in the control group but remained unchanged in the elderly patients. The stroke index （SI） increased in the control group （P 〈 0. 05 vs. before HHD） but no marked changes were seen in the elderly patients. The systemic vascular resistance （TSVR） decreased in the younger patients （P 〈0.05） but increased about 19% in the elderly patients after hemodilution. No statistically significant changes in any variables were found in the elderly patients after HHD. No correlation was found between changes in hemodynamics and patient ages. CONCLUSIONS：Acute HHD is not well tolerated during anesthesia by elderly patients without heart diseases. HHD leads to a decrease in cardiac output that is generated initially from a decrease in SV. The results indicate that elderly patients have a limited compensatory cardiovascular capacity during HHD.