FP518HYDRATION STATUS: NOT JUST A MATTER OF NUMBERS

Abstract

Introduction and Aims: The optimization of dry weight estimation with reliable tools in patients treated with hemodialysis is mandatory to reduce cardiovascular (CV) risk and increase survival. In the last decade, several studies underscored the importance of minimizing interdialytic weight gain in order to reduce the occurrence of major CV events (acute myocardial infarction, acute pulmonary edema) and hospitalization rate (Kalantar‐Zadeh K et al. Circulation 2009;119:671‐679 ,Foley RN et al. N Engl J Med 2011;365:1099‐1107,Lee MJ et al. Am J Nephrol 2014;39:427‐435). The aim of this study was to compare two different techniques, bioelectrical impedance vectorial analysis (BIVA) and the assessment of B‐lines by pulmonary ultrasonography (US) for the detection of cardio‐pulmonary congestion in hemodialysis patients. Methods: Fifty‐four patients, 31 females and 23 males; age 67 years referring to the Hemodialysis outpatient clinic at the Hospital of Perugia were enrolled. Forty‐four patients were treated with three‐times a week hemodialysis (4 hours each) and 10 with daily hemodialysis (2 hours each). Clinical, BIVA and US assessment were performed after the last hemodialysis of week and before the first hemodialysis of the subsequent week. BIVA was performed with Akern Bia 101® bioimpedenziometer and US scan with Hitachi® ALOKA and 7.5MHz linear probe. According to BIVA, hyperhydration status was defined under the 75% tolerance ellipse plot. Concerning pulmonary US, hyperhydration status was defined by the presence of more than 15 B‐lines in 28 intercostal spaces.We assessed the differences in Kg with bed scale and derived by bioimpedance. Results: According to BIVA, hyperhydration status was present in 21 out of 51 patients (41.2%) but only in 6 this was confirmed by pulmonary US. According to pulmonary B‐lines, hyperhydration status was present in 7 out of 51 patients (13.7%) and only in 1 this was confirmed by BIVA. No significant correlation was observed between interdialitic weight gain evaluated by bed scale and water increase in liters estimated with BIVA. There was a significantly differences in Kg between bedscale and bioimpedance. These means that bioimpedance is not useful for detection of body fluid changes. Conclusions: Our results suggest that BIVA is reliable, time‐saving and easy to employ in clinical practice to evaluate hydration status of hemodialysis patients. Pulmonary B‐lines failed to correctly estimate systemic hyperhydration but efficiently reflected heart‐related pulmonary congestion. BIVA graphical approach, rather than its quantitative value, is useful and not misleading in the quantitative estimation of hydration status. (Figure presented).