title: Usefulness of segmental bioimpedance ratio to determine dry body weight in new hemodialysis patients: a pilot study.
abstract: BACKGROUND
  The ratio of bioimpedance in the right leg (rl-RBI) may be helpful in adjusting dry body weight (DBW) in new hemodialysis (HD) patients.
  
  
  METHODS
  rl-RBI was calculated as follows: rl-RBI = impedance at 50 kHz/impedance at 500 kHz, as measured by bioimpedance spectroscopy (BIS). Theoretically, rl-RBI is inversely related to extracellular water. A reference range of rl-RBI was obtained from 137 chronic but stable HD patients already achieving DBW. In 34 new HD patients (females:males = 16:18; age 49 +/- 12 years), DBW(s) were stepwise adjusted under the guidance of rl-RBI by modifying the amount of ultrafiltration.
  
  
  RESULTS
  The target range of rl-RBI was defined as 1.106-1.150. rl-RBI before the first HD was 1.115 +/- 0.027. At the study endpoint, when the target range of rl-RBI was achieved, pretibial pitting edema and pulmonary edema were resolved without any episode of muscle cramping or intradialytic hypotension. Along with an increase in rl-RBI, pre-HD blood pressure tended to decrease at systole (p = 0.072) and diastole (p = 0.005). The cardiothoracic ratio also decreased significantly (p = 0.004).
  
  
  CONCLUSIONS
  The measurement of rl-RBI by BIS is worthy of further evaluation as an objective and applicable index for determining DBW in new HD patients.
authors.affiliation: Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Jongha
authors.initials: J
authors.lastname: Park
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Yang
authors.forename: Soon Bae
authors.initials: SB
authors.lastname: Kim
authors.forename: Su-Kil
authors.initials: SK
authors.lastname: Park
authors.forename: Sang Koo
authors.initials: SK
authors.lastname: Lee
authors.forename: Jung Sik
authors.initials: JS
authors.lastname: Park
authors.forename: Jai Won
authors.initials: JW
authors.lastname: Chang
mesh_terms: D000328:Adult; D001823:Body Composition; D001825:Body Fluid Compartments / Q000502:physiology; D001835:Body Weight; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011654:Pulmonary Edema / Q000473:pathology; D012044:Regression Analysis; D006435:Renal Dialysis / Q000379:methods* / Q000592:standards