Bioelectrical impedance spectroscopy in health and disease. Correspondence between whole body and segmental bioelectrical impedance spectroscopy indices in patients with classical dengue fever.

Bioelectrical impedance spectroscopy (BIS) can provide estimates of body composition for both whole body (WB) and body segments (BS). In normal, healthy subjects, BS measurements may be expected to serve as surrogates for WB indices; however, very little is known about this correspondence in people suffering from acute illnesses. The aim of this study was to evaluate the degree of this correspondence in patients with an acute, systemic illness, such as classical dengue fever. Ten adult patients were examined upon admission to the community hospital on the Pacific Coast of Guatemala and after clinical recovery about two weeks later, and compared with a group of healthy subjects living in the same region. BIS was measured with a Xitron 4000B analyzer (Xitron Technologies Inc., San Diego, CA, USA). BS measurements were carried out using Organ et al.'s approach. The BIS data were modeled with the manufacturer's software: extra- (Recf) and intracellular- (Ricf) resistances, and the Recf/Ricf ratio. BIS BS measurements correlate closely with WB in both the acute and the recovery stages of dengue fever, with the leg showing the highest degree of correspondence and the trunk the lowest. Recf indices, per se, generally showed higher correspondence than Ricf or the Recf/Ricf ratio.