title: Whole-body and thoracic bioimpedance measurement: hypertension and hyperhydration in hemodialysis patients.
abstract: Mono-frequency (50 kHz) and multi-frequency (3 kHz - 1 MHz) whole-body and thoracic segment bioimpedance measurement were doing before and after hemodialysis session in 20 patients. The patients were classified in hypertensive or non-hypertensive according to the mean blood pressure, BPmean. The relation between hyper-hydration in thorax segment through real part of impedance and mean blood pressure was analyzed. Also the bioelectrical impedance vector analysis method was used to analyze the displacement of Z/H vector in order to establish the relation with hyper-hydration (edema). Finally we made multi-frequency measurements with the objective to find a significative change in high and low frequency. We obtained a significant difference (P < 0.05) in impedance parameters before and after HD session. Some patients are located in hyper-hydration zone, below the inferior pole of the 75% tolerance ellipse, whereas others patients were within the tolerance ellipses. The real part of the impedance in thorax region can identify over-hydrated patients with an increased risk for cardiovascular disease associate to hypertension. Multi-frequency bioimpedance measurement show an important change at low and high frequency and indicate that is possible to obtain more information about extra-cellular or intra-cellular fluid status, to find the relation between fluid loads, bioimpedance parameters, extra-cellular water, and blood pressure.
authors.forename: L
authors.initials: L
authors.lastname: Nescolarde
authors.forename: P
authors.initials: P
authors.lastname: Bogónez
authors.forename: J
authors.initials: J
authors.lastname: Calpe
authors.forename: R
authors.initials: R
authors.lastname: Hernández
authors.forename: T
authors.initials: T
authors.lastname: Doñate
authors.forename: J
authors.initials: J
authors.lastname: Rosell
mesh_terms: D002307:Cardiography, Impedance / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004487:Edema / Q000175:diagnosis* / Q000209:etiology; D017097:Electric Impedance; D005260:Female; D006801:Humans; D006977:Hypertension, Renal / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D010993:Plethysmography, Whole Body / Q000379:methods*; D006435:Renal Dialysis / Q000009:adverse effects*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000209:etiology