Effects of ventilation on reproducibility of bioimpedance spectroscopy fluid ratio measures

The aim of this study was to determine the score reproducibility of the observed extracellular-to-intracellular fluid (ECF/ICF) scores using generalizability theory across three ventilation conditions of the trunk and forearm segments. The test instrument employed was a Xitron Hydra ECF/ICF bioimpedance analyzer system Model 4200. Volunteer subjects were healthy North American males (n = 50) and females (n = 50), 18-71 years. Each segment was tested on a one-trial test, for each of the three ventilation conditions. The single trial was six continuous time measures, taken 5 s apart during a 30 s time period. The three ventilation conditions were the following: normal ventilation, regimented breathing and no ventilation. A two-facet, person-by-time, fully crossed design was used; all facets were treated as random. The ECF/ICF data for each segment were independently analyzed for each ventilation condition and each gender group. The findings were as follows. (1) The reproducibility of scores improved by using the forearm segment compared to the trunk segment, (2) breath holding improves the reproducibility of test scores compared to normal breathing on men's trunk scores, (3) breath holding was not superior to normal breathing on women's trunk scores.