Matthie J, Zarowitz B, De Lorenzo A, Andreoli A, Katzarski K, Pan G, Withers P
Medical Department, Xitron Technologies, San Diego, California 92121, USA.
J Appl Physiol (1985). 1998 May;84(5):1801-16. doi: 10.1152/jappl.1998.84.5.1801.
Knowledge of patient fluid distribution would be useful clinically. Both single-frequency (SF) and impedance modeling approaches are proposed. The high intercorrelation between body water compartments makes determining the best approach difficult. This study was conducted to evaluate the merits of an SF approach. Mathematical simulation was performed to determine the effect of tissue change on resistance and reactance. Dilution results were reanalyzed, and resistance and parallel reactance were used to predict the intracellular water for two groups. Results indicated that the amount of intracellular and extracellular water conduction at any SF can vary with tissue change, and reactance at any SF is affected by all tissue parameters. Modeling provided a good prediction of dilution intracellular and extracellular water, but an SF method did not. Intracellular, extracellular, and total body water were equally predicted at all frequencies by SF resistance and parallel reactance. Extracellular and intracellular water are best measured through modeling, because only at the zero and infinite frequencies are the results sensitive only to extracellular and intracellular water. At all other frequencies there are other effects.
了解患者的体液分布在临床上会很有用。有人提出了单频（SF）和阻抗建模方法。由于身体水室之间的高度相互关联，很难确定最佳方法。本研究旨在评估SF方法的优点。进行了数学模拟以确定组织变化对电阻和电抗的影响。重新分析了稀释结果，并使用电阻和并联电抗来预测两组的细胞内水。结果表明，在任何单频下，细胞内和细胞外水传导的量会随组织变化而变化，并且任何单频下的电抗都会受到所有组织参数的影响。建模能很好地预测稀释后的细胞内和细胞外水，但单频方法则不行。单频电阻和并联电抗在所有频率下对细胞内、细胞外和总体水的预测效果相同。细胞外和细胞内水最好通过建模来测量，因为只有在零频率和无限频率下，结果才仅对细胞外和细胞内水敏感。在所有其他频率下都存在其他影响。
