Evaluation de l’état hydrique chez les patients hémodialysés chroniques : une étude transversale monocentrique: Assessment of the hydration status in chronic hemodialysis patients: a single-center cross-sectional study

Context and objective. For many practitioners, blood pressure is the main indicator of the hydration status of the chronic hemodialysis patient. The objective of this study was to assess the extent to which bioimpedance analysis (BIA) can assist in determining acute changes in fluid volume during the hemodialysis session. Methods. This was a 9-week longitudinal study. The total body water (TBW) was measured with a BIA analyzer, before and after 6 successive sessions. The ΔWeight was compared to the ΔTBW by calculating the P/V ratio (ΔWeight/ΔTBW) with the assumption that the dry weight is reached when P/V = 1. Results. The measurements made in 22 patients (46.6 years, 54.5% men, 92.3 months on dialysis) were reproducible. There was no statistically significant difference between ΔTBW and ΔWeight. However, at the individual level, significant differences had been observed. Using hypertension as a marker for a state of hyperhydration, a 31.8% agreement was noted between the P/V ratio and hypertension. Conclusion. Although the loss of water predicted by the BIA did not always correspond to the weight loss, BIA is a technique that can be used to assess the variations in TBW during the hemodialysis session in patients. Contexte et objectif. La pression artérielle est pour de nombreux praticiens, l’indicateur principal du statut hydrique du patient hémodialysé chronique. L’objectif de la présente étude était d’évaluer dans quelle mesure l’analyse d’impédance bioélectrique (BIA) pourrait aider à la détermination des variations aigues du volume hydrique au cours de la séance d’hémodialyse. Méthodes. Il s’agissait d’une étude de suivi longitudinal sur 9 semaines. Le volume total d’eau (VTE) a été mesuré par BIA, avant et après 6 séances. Le ΔPoids a été comparé au ΔVTE par le calcul du ratio P/V (ΔPoids / ΔVTE) dans l’hypothèse que le poids sec est atteint lorsque P/V = 1. Résultats. Les mesures faites chez 22 patients (46,6 ans, 54,5% hommes, 92,3 mois en dialyse) étaient reproductibles. Il n’y avait pas de différence statistiquement significative entre le ΔVTE et le ΔPoids. Cependant à l’échelon individuel des différences importantes étaient observées. En utilisant l’hypertension artérielle (HTA) comme marqueur d’un état d’hyperhydratation, une concordance de 31,8% était notée entre le ratio P/V et l’HTA. Conclusion. Bien que la perte d’eau prédite par la BIA ne corresponde pas toujours à celle du poids, la BIA est une technique qui peut être utilisée pour évaluer les variations du VTE au cours de la séance d’hémodialys

Usefulness of foot-to-foot bioimpedance analysis for assessing volume status in chronic hemodialysis patients at the Aristide Le Dantec University Hospital (Senegal)

Introduction: Determination of dry weight is one of the daily goals to achieve in hemodialysis. The aim of this study was to validate the use of bioelectrical impedance analysis (BIA) in estimation of dry weight in a population of Senegalese chronic hemodialysis patients. Patients and methods: A 9-week cross-sectional study was carried out at the hemodialysis unit of Aristide Le Dantec University Hospital. Adult patients with no previous hospital history were included. The total body water (TBW) was measured with a single frequency bioelectric impedance foot-to-foot analyzer, before and after six successive hemodialysis sessions. These results were compared with those from clinical measurements with the Watson equation using a Student’s t-test and Bland-Altman analysis. Results: 264 measurements were made in 22 patients (46.6 years, 54.5% men, 92.3 months on dialysis, 62.7 kg mean dry weight). A significant reduction in weight (ΔWeight = 2.0 ± 1.1 kg; p < 0.0001) and in TBW measured by the BIA (ΔTBWBIA = 3.3 ± 1.0 liters; p < 0.0001)) or calculated by Watson’s equation (ΔTBWWatson = 0.5 ± 0.2 liter; p = 0.0001) was observed. There was a strong linear correlation and agreement between the 2 TBW measurements in pre-dialysis. In post-dialysis the concordance diagram indicated a bias = –2.2 and wide agreement limits. Conclusion: The BIA allows reproducible and reliable measurements and a fair estimate of the TBW in pre-dialysis