Fuller H D
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Ann Biomed Eng. 1991;19(2):123-9. doi: 10.1007/BF02368464.
To evaluate the role of plasma chemistry in the genesis of electrical impedance of blood, a laboratory simulation was performed using solutions prepared so as to mimic plasma chemistry abnormalities that are seen in the critically ill. There was a 15% increase of impedance due to decrease in sodium chloride concentration from 140 mmol/L to 120 mmol/L, and a 12% decrease of impedance due to increase in sodium chloride to 160 mmol/L. Impedance changes secondary to other chemistry abnormalities were small and probably not significant, with the exception of a change of albumin concentration from 80 gm/L to 50 gm/L, which induced a 6% increase in impedance. Using this data, a model was constructed to predict changes in whole blood resistivity, and this was extrapolated in two simulations of plasma chemistry abnormalities to predict alterations of calculated impedance stroke volume in excess of 5%.
为评估血浆化学成分在血液电阻抗产生中的作用，我们进行了一项实验室模拟，使用的溶液是为模拟危重症患者中出现的血浆化学成分异常而配制的。由于氯化钠浓度从140 mmol/L降至120 mmol/L，阻抗增加了15%；而由于氯化钠浓度增至160 mmol/L，阻抗降低了12%。除白蛋白浓度从80 g/L降至50 g/L导致阻抗增加6%外，其他化学成分异常引起的阻抗变化较小且可能不显著。利用这些数据构建了一个模型来预测全血电阻率的变化，并在两个血浆化学成分异常模拟中进行外推，以预测计算的阻抗心搏量变化超过5%。
