Sebastian Wieskotten

Importance of normohydration for the long-term survival of haemodialysis patients

BACKGROUND Fluid overload and hypertension are among the most important risk factors for haemodialysis (HD) patients. The aim of this study was to analyse the impact of fluid overload for the survival of HD patients by using a selected reference population from Tassin. METHODS A positively selected HD population (n = 50) from Tassin (Lyon-France) was used as a reference for fluid status and all-cause mortality. This population was compared to one dialysis centre from Giessen (Germany) which was separated into a non-hyperhydrated (n = 123) and a hyperhydrated (n = 35) patient group. The hydration status (ΔHS) of all patients was objectively measured with whole-body bioimpedance spectroscopy in 2003. All-cause mortality was analysed after a 6.5-year follow-up. RESULTS Most of the reference patients from Tassin were normohydrated (ΔHS = 0.25 ± 1.15 L) at the start of the HD session. The hydration status of the Tassin patients was not different to the non-hyperhydrated Giessen patients (ΔHS = 0.8 ± 1.1 L) but significantly lower than in the hyperhydrated Giessen group (ΔHS = 3.5 ± 1.2 L). Multivariate adjusted all-cause mortality was significantly increased in the hyperhydrated patient group (hazard ratio = 3.41)- no difference in mortality could be observed between the Tassin and the non-hyperhydrated group from Giessen-even considering the fact that Tassin patients presented a significantly lower blood pressure. CONCLUSIONS Fluid overload has a very high predictive value for all-cause mortality and seems to be one of the major killers in the HD population. Patients might strongly benefit from active management of fluid overload.

Physical methods for evaluating the nutrition status of hemodialysis patients

This article aims to provide an overview of the different nutritional markers and the available methodologies for the physical assessment of nutrition status in hemodialysis patients, with special emphasis on early detection of protein energy wasting (PEW). Nutrition status assessment is made on the basis of anamnesis, physical examination, evaluation of nutrient intake, and on a selection of various screening/diagnostic methodologies. These methodologies can be subjective, e.g. the Subjective Global Assessment score (SGA), or objective in nature (e.g. bioimpedance analysis). In addition, certain biochemical tests may be employed (e.g. albumin, pre-albumin). The various subjective-based and objective methodologies provide different insights for the assessment of PEW, particularly regarding their propensity to differentiate between the important body composition compartments—fluid overload, fat mass and muscle mass. This review of currently available methods showed that no single approach and no single marker is able to detect alterations in nutrition status in a timely fashion and to follow such changes over time. The most clinically relevant approach presently appears to be the combination of the SGA method with the bioimpedance spectroscopy technique with physiological model and, additionally, laboratory tests for the detection of micro-nutrient deficiency.

Modell-basierte Erkennung von Mangelernährung mittels Bioimpedanzspektroskopie (Model-based Identification of Malnutrition via Bioimpedance Spectroscopy)

Protein-Energie-Mangelernährung bei Patienten reduziert die Lebensqualität, verlängert die Krankenhausverweildauer und erhöht drastisch die Mortalität. Aktuell existiert kein einfaches und objektives Verfahren zur Bestimmung des Ernährungsstatus und damit zur Erkennung von Mangelernährung. Mithilfe einer Bioimpedanzmessung kann mit einem neu entwickelten Expertensystem Mangelernährung bei Patienten erkannt werden. Die Funktionsweise des Expertensystems orientiert sich an der technischen Fehlerdiagnose. Protein-energy-malnutrition reduces the quality of life, lengthens the time in hospital and increases the mortality dramatically. Currently there is no simple and objective method available for assessing the nutritional status and thus identifying malnutrition. A newly developed expert system detects patients with malnutrition via a bioimpedance measurement. The system is based on the technical fault diagnosis.