Drobin D, Hahn R G
Department of Anesthesia, South Hospital, Stockholm, Sweden.
Anesthesiology. 1999 Jan;90(1):81-91. doi: 10.1097/00000542-199901000-00013.
The amount of Ringer's solution needed to restore normal blood volumes is thought to be three to five times the volume of blood lost. This therapy can be optimized by using a kinetic model that takes accounts for the rates of distribution and elimination of the infused fluid.
The authors infused 25 ml/kg Ringer's acetate solution into 10 male volunteers who were 23 to 33 yr old (mean, 28 yr) when they were normovolemic and after 450 ml and 900 ml blood had been withdrawn. One-volume and two-volume kinetic models were fitted to the dilution of the total venous hemoglobin and plasma albumin concentrations.
Withdrawal of blood resulted in a progressive upward shift of the dilution-time curves of both markers. The two-volume model was statistically justified in 56 of the 60 analyzed data sets. The hemoglobin changes indicated that the body fluid space expanded by the infused fluid had a mean total volume of 10.7 l(+/-0.9 SEM). The elimination rate constant (kr) decreased with the degree of hypovolemia and was 133 ml/min (22 ml/min [SEM]), 100 ml/min (39 ml/min [SEM]), and 34 ml/min (7 ml/min [SEM]), respectively (P < 0.01). Plasma albumin indicated a slightly larger body fluid space expanded by the infused fluid, but kr was less (P < 0.02). Hypovolemia reduced the systolic and diastolic blood pressures by approximately 10 mmHg (P < 0.05).
The dilution of the blood and the retention of infused Ringer's solution in the body increases in the presence of hypovolemia, which can be attributed chiefly to a reduction of the elimination rate constant.
恢复正常血容量所需的林格氏液量被认为是失血量的三到五倍。通过使用考虑输注液体分布和消除速率的动力学模型，可以优化这种治疗方法。
作者将25ml/kg的醋酸林格氏液输注到10名年龄在23至33岁（平均28岁）的男性志愿者体内，这些志愿者在血容量正常时以及分别失血450ml和900ml后接受输注。单室和双室动力学模型被用于拟合总静脉血红蛋白和血浆白蛋白浓度的稀释情况。
失血导致两种标志物的稀释时间曲线逐渐向上移动。在60个分析数据集中，有56个数据集在统计学上支持双室模型。血红蛋白的变化表明，输注液体所扩张的体液空间平均总体积为10.7升（±0.9标准误）。消除速率常数（kr）随着低血容量程度的增加而降低，分别为133ml/min（22ml/min[标准误]）、100ml/min（39ml/min[标准误]）和34ml/min（7ml/min[标准误]）（P<0.01）。血浆白蛋白表明输注液体所扩张的体液空间略大，但kr较小（P<0.02）。低血容量使收缩压和舒张压降低约10mmHg（P<0.05）。
在低血容量情况下，血液稀释和输注的林格氏液在体内的潴留增加，这主要归因于消除速率常数的降低。
