Bioimpedance spectroscopy for the differential diagnosis of hyponatremia.

BACKGROUND: Hyponatremia is classified according to volume status with the help of physical examination, biochemical measures, urine and serum osmolalities, and echocardiography. Bioimpedance spectroscopy (BIS) has been getting popularity for revealing tissue compositions of various patient groups. The aim of this observational study was to investigate the role of BIS for the differential diagnosis of hyponatremia (ClinicalTrials.gov Identifier: NCT01838759). PATIENTS AND METHODS: Personal characteristics of age, sex, weight, height, and blood pressure were recorded. Body composition monitor (BCM) was used for hydration status for each individual. Primary outcome was investigated by the accuracy of volume status measured by BIS. STATISTICS: Kappa statistic (K) is a measure of agreement between two sources, which is measured on a binary scale (i.e., condition present/absent). K statistic can take values between 0 and 1: poor agreement: K < 0.20, fair agreement: 0.2.0-0.3.9, moderate agreement: 0.40-0.59, substantial: 0.60-0.79, very good agreement: 0.80-1.00. RESULTS: Fifty-eight hyponatremia-diagnosed patients, 32 (55.2%) of male with the mean age of 65.2 ± 11 (40-89) years were included. Kappa statistic (K) were very good (K = 0.925) for male (p < 0.00), substantial agreement (K = 0.601) for female (p < 0.002) with the use of BIS for the differential diagnosis of either hypo or hypervolemia in hyponatremic patients compared with gold standard tests which were the combination of echocardiography, serum, and urine osmolality biochemical tests, and physical examination. CONCLUSION: Bioimpedance spectroscopy is a practical and an inexpensive method. This is the first study in the literature showing the role of BIS for the determination of the volume status and differential diagnosis of hyponatremia when compared with echocardiography.

Hypervolemia for hypertension pathophysiology: a population-based study.

OBJECTIVES: Hypertension and hypervolemia relationship was proven among renal disease, although it is not known in normal population. Present study determines the fluid distribution defects in relation to blood pressure. MATERIAL AND METHODS: In a population-based survey in Turkey demographics, height, weight, blood pressure, urine analysis, and serum creatinine measurements were recorded. Bioimpedance measured with the Body Composition Monitor. RESULTS: Total 2034 population of 71.6% male, mean age 47 ± 12.6 (18-89) years, systolic blood pressure (SBP) 134.7 ± 20, diastolic blood pressure 77.9 ± 11.6 mmHg. Body mass index (BMI) was 28.5 ± 4.5 (15.8-50.6) kg/m(2); overhydration was 0.05 ± 1.05 L. There was a correlation between extracellular water (ECW)/height and SBP (r = 0.21, P < 0.001). Receiver operating characteristic (ROC) curve with the performance of 0.60 (P < 0.001) that showed cut-off value of ECW/height was 10.06 L/m, with the 69% sensitivity and 45% specificity for SBP: 140 mmHg values. Risk factors for high SBP were increase of ECW/Height, age, BMI and presence of diabetes. ECW/height, SBP, and fat tissue index (FTI) increased in BMI categories (low, normal, and obese) and in diabetics. SBP and FTI were lower in smokers. CONCLUSIONS: High blood pressure may be accompanied by increased extracellular volume indices. In the future volume status assessment could be of use in evaluating the effectiveness of pharmacological intervention in the treatment of hypertension.

The effects of strict salt control on blood pressure and cardiac condition in end-stage renal disease: prospective-study.

INTRODUCTION: Overhydration is the main contributory factor of left ventricular hypertrophy and closely associated with cardiovascular events in end stage renal disease (ESRD) patients. The aim of this prospective-study was to investigate the impact of strict salt and volume control on hypertension and cardiac condition in ESRD patients. METHODS: A total of 12 peritoneal dialysis (PD) and 15 prevalent hemodialysis (HD) patients were enrolled. All patients either PD or HD were allocated to intervention of strict salt restriction according to basal hydration state of empty abdomen in PD and midweek predialysis HD which were estimated by body composition monitor (BCM) and echocardiography. RESULTS: Mean ages were 48.3 ± 16.7 years for PD, and 48.8 ± 18 for HD patients. Extracellular water/height was 10.04 ± 2.70 and 10.39 ± 1.53 L/m in PD and HD groups. Systolic blood pressures decreased in PD and HD from 133.1 ± 28 and 147.3 ± 28.5 to 114.8 ± 16.5 and 119.3 ± 12.1 mmHg, respectively, (p < 0.00). IDKA/DW were decreased from 3.26 ± 1.6 to 2.97 ± 1.63 % in HD group (p > 0.05). LVMI and LAI were not increased in both groups. CONCLUSION: Strict salt and volume control in ESRD patients after assessment of hydration status with either using BCM or echocardiography provides better management of volume control leading to more precise cardiovascular protection.