ABSTRACT
BACKGROUND: Accurate volume measurement is important in the management of patients with congestive heart failure or renal insufficiency. A bioimpedance analyser can estimate total body water in litres and has been widely used in clinical practice due to its non-invasiveness and ease of results interpretation. To change impedance data to volumetric data, bioimpedance analysers use equations derived from data from healthy subjects, which may not apply to patients with other conditions. Bioelectrical impedance vector analysis (BIVA) was developed to overcome the dependence on those equations by constructing vector plots using raw impedance data. BIVA requires normal reference plots for the proper interpretation of individual vectors. The aim of this study was to construct normal reference vector plots of bioelectrical impedance for Koreans. METHODS: Bioelectrical impedance measurements were collected from apparently healthy subjects screened according to a comprehensive physical examination and medical history performed by trained physicians. Reference vector contours were plotted on the RXc graph using the probability density function of the bivariate normal distribution. We further compared them with those of other ethnic groups. RESULTS: A total of 242 healthy subjects aged 22 to 83 were recruited (137 men and 105 women) between December 2015 and November 2016. The centers of the tolerance ellipses were 306.3 Ω/m and 34.9 Ω/m for men and 425.6 Ω/m and 39.7 Ω/m for women. The ellipses were wider for women than for men. The confidence ellipses for Koreans were located between those for Americans and Spaniards without overlap for both genders. CONCLUSION: This study presented gender-specific normal reference BIVA plots and corresponding tolerance and confidence ellipses on the RXc graph, which is important for the interpretation of BIA-reported volume status in patients with congestive heart failure or renal insufficiency. There were noticeable differences in reference ellipses with regard to gender and ethnic groups.
Subject(s)
Adult , Female , Humans , Male , Blood Volume , Body Fluid Compartments , Body Water , Electric Impedance , Ethnicity , Healthy Volunteers , Heart Failure , Physical Examination , Renal InsufficiencyABSTRACT
Fundamento: los avances tecnológicos en el campo de la electrónica y la informática han proporcionado grandes mejoras en la seguridad y tolerancia a la hemodiálisis. La incorporación de biosensores que informan del desarrollo de la sesión de hemodiálisis en tiempo real ha supuesto una novedad relevante. Objetivo: profundizar sobre la utilidad y los principios de los biosensores aplicados a las máquinas actuales de la hemodiálisis. Método: se realizó una revisión de investigaciones publicadas en revista de nefrología biomed.uninet; asn-online.org y scielo., libros, revistas y manuales de funcionamiento de las máquinas de hemodiálisis seleccionándose 34 artículos científicos sobre los biosensores y su empleo. Desarrollo:revisión de los avances tecnológicos en las máquinas de hemodiálisis, los biosensores existentes, con las señales captadas por el sensor, su equivalente biológico y la señal clínica que nos aportan. Conclusiones: los biosensores son monitores que, a través de señales fisicoquímicas obtenidas del circuito extracorpóreo de sangre o del baño de diálisis, proporcionan datos de la eficacia de la sesión de hemodiálisis o de los cambios que produce en el medio interno del enfermo.
Background: technological advances in the fields of electronics and computer science have provided great improvements concerning safety and tolerance to haemodialysis. The incorporation of biosensors that inform about the progress of the haemodialysis session in real time has meant a significant innovation. Objective: to look in depth at the usefulness and principles of biosensors applied to current haemodialysis machines. Method: a review of researches published in nephrology journals, biomed.uninet, as-online.org, Scielo, books, other journals, and training manuals about the workings of haemodialysis machines, was made. Thirty-four scientific articles related to biosensors and the instructions for their use, were selected. Development: a review of the technological advances related to haemodialysis machines, the existing biosensors, the signals received by the sensor, the biological equivalent and the clinical signal they contribute with, was made. Conclusions: biosensors are monitors that, by means of physical-chemical signals obtained from the extracorporeal circuit of blood or of the dialysis bath, provide information of the effectiveness of the session of haemodialysis or of the changes that it produces in the organism of the patient.
ABSTRACT
Objective To investigate the abnormality of fluid distribution and its effect on blood pressure (BP) in hemodialysis patients. Methods One hundred and six healthy volunteers as normal controls were divided into two groups(male group and female group).ECV%?ICV%(% means a percentage of weight) and ECV/ICV were measured by bioelectrical impedance spectroscopy and calculated in 2 groups respectively.Sixty-seven stable HD patients who had been on HD for more than 2 months in our hospital were selected. Patients were divided into 4 groups (hypotension prone group, normotensive group, hypertensive group and refractory hypertensive group). ECV%, ICV% and ECV/ICV were measured and calculated as above immediately before and after HD session. The measurement was conducted by Xitron 4200 HYDRA ECF/ICF Bio-Impedance Spectrum Analyzer. Results In patients on HD, a significant decrease of ECV% and ECV/ICV, and a significant increase of ICV% were seen post-HD. The pre-HD ECV% and ECV/ICV were significantly higher than those of normal controls but dropped close to normal level after hemodialysis. Post-HD ECV% was still higher than that of normal controls[(31.6?1.0)% vs (25.3?1.6)%, P 0.05]and post-HD ECV% of these patients was significantly lower than that of normal controlsand post-HD ECV% of these patients was significantly lower than that of normal controls[(19.3?1.6)% vs (22.6?1.4)%,P