Abstract

Purpose: Accurate assessments of body fluid balance and nutritional status in patients with critical illness are challenging to clinicians. Because existing parameters have some limitations, this study was designed to evaluate the usefulness of bioelectrical impedance as an assessment tool for body fluid balance and nutritional status.
Materials and Methods: We retrospectively reviewed the medical records of 17 patients treated in surgical intensive care units, which included 16 patients for postoperative care and one patient for medical treatment. Body water status, basal metabolic rate, body cell mass, and fat free mass were examined serially by bioelectrical impedance. Based on body mass index and mortality, we determined whether there were differences among the measured results.
Results: There were 3 mortality cases. According to body mass index, the underweight, normoweight, overweight, and mild obese groups included 2, 7, 2, and 6 patients, respectively. The mixed effects model revealed significant differences within individual extracellular water/total body water (ECW/TBW) (P=0.009), total body water (P=0.025), extracellular water (P=0.033), and intracellular water (P=0.022). The variation of ECW/TBW revealed there was a significant difference between the survival and non-survival patients (P=0.034). Basal metabolic rate (BMR), fat free mass (FFM), and body cell mass (BCM) were directly proportional to arm muscle circumference with high Pearson’s coefficiency (BMR, r=0.727; FFM, r=0.727, BCM, r=0.651).
Conclusion: Bioelectrical impedance analysis is a noninvasive and simple bedside method to assess changes in body fluid balance and nutrition status. Future research should prospectively investigate more patients and compare bioelectrical impedance analysis results with classical assessment tools to validate these results. (SMN 2010;1:30-35)

• Keywords: Body fluid, Nutrition status, Bioelectrical impedance analysis