Fiorotto M L, Klish W J
Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston.
Clin Perinatol. 1991 Sep;18(3):611-27.
TOBEC measurements are based on the premise that a conductive object will interact with an electromagnetic field and result in the dissipation of a small quantity of the field's energy. TOBEC instruments provide a measure of this energy loss, which for a given conductor varies according to its size. The conductive component of the body is that part that contains water with dissolved electrolytes, i.e., essentially the FFM. Fat, by definition, is anhydrous and does not contribute to a TOBEC measurement. To interpret TOBEC readings in terms of the quantity of FFM in the body requires the use of a calibration equation that is generated by measuring the FFM of a reference population using an alternative technique and relating this to each individual's TOBEC value. Because no alternative method exists to estimate the FFM of an infant, a calibration equation is used that was generated from measurements of young miniature piglets. The body composition of infants thus derived is consistent with our general understanding of the changes in fat and FFM in human infants in early life. Whether TOBEC can be used as described in premature or older children has yet to be determined. Variations in the composition of the FFM do not seem to compromise the accuracy of the technique. TOBEC measurements are precise, rapid, noninvasive, and safe and cause the subject no discomfort. These features not only make TOBEC a useful tool for the nutritional assessment of a pediatric patient but they also may be a useful diagnostic tool for the clinician.
全身体液导电率（TOBEC）测量基于这样一个前提：导电物体与电磁场相互作用会导致少量场能的耗散。TOBEC仪器可测量这种能量损失，对于给定导体，该能量损失会因其大小而异。身体的导电成分是含有溶解电解质的水的部分，即基本上是去脂体重（FFM）。根据定义，脂肪是无水的，对TOBEC测量没有贡献。要根据体内FFM的量来解释TOBEC读数，需要使用校准方程，该校准方程是通过使用另一种技术测量参考人群的FFM并将其与每个人的TOBEC值相关联而生成的。由于不存在估计婴儿FFM的替代方法，因此使用的校准方程是根据幼年小型仔猪的测量结果生成的。由此得出的婴儿身体成分与我们对人类婴儿早期脂肪和FFM变化的一般理解是一致的。TOBEC是否能如所述用于早产儿或大龄儿童，还有待确定。FFM组成的变化似乎并未影响该技术的准确性。TOBEC测量精确、快速、无创且安全，不会给受试者带来不适。这些特性不仅使TOBEC成为儿科患者营养评估的有用工具，对临床医生而言它也可能是一种有用的诊断工具。
