Fluid Management in Haemodialysis : Studies on current practices and new methods

Abstract: Chronic fluid overload has been identified as an independent predictor of mortality in haemodialysis patients, and 30% remain fluid overloaded at dry weight. The use of bioimpedance spectroscopy (BIS) in fluid management may improve blood pressure control and cardiovascular status. However, the importance of regular and careful clinical assessment of fluid balance is repeatedly emphasised.This thesis is based on five papers and the overall aim was to investigate current practices and new methods for fluid management in haemodialysis, and to develop a management tool for dry weight determination, based on multiple complementary methods. The purpose was to contribute to reduced prevalence of fluid overload and intradialytic symptoms in haemodialysis patients, by providing the healthcare team and the patient with a tool, that facilitates communication and enables informed decision-making in dry weight determination.In the initial, cross-sectional study, clinical praxis for dry weight assessment in Sweden and Denmark was investigated. A wide variation in routines was found. Despite high access, BIS was sparsely used. Instead, nurses’ authorisation to adjust haemodialysis patients’ dry weight was associated with improved fluid status. The second study had a qualitative approach. Focus group interviews, with healthcare professionals, were carried out to achieve a deeper understanding of the factors preventing or facilitating the use of BIS. In the third study, the usefulness of a biomarker, brain natriuretic peptide (BNP), for assessing fluid status in haemodialysis patients, was investigated. An association between BNP and fluid overload was established. The between-individual variation in BNP levels was greater than the within-individual variation over time. Therefore, if BNP is to be used as a marker for fluid overload, repeated measurements are required. In the fourth study, we developed and validated a multifactorial decision aid, Recova®, that incorporates BIS in dry weight determination. Recova® is based on physiological parameters routinely measured in haemodialysis and provides guidance on when and how to respond to recognised fluid alterations. In the fifth study, the decision aid’s effect on volume status was tested in a cohort of haemodialysis patients. Implementation of Recova® had effect on fluid status symptoms, BIS-measured hydration status and NT-proBNP levels.