Longitudinal bioimpedance assessments to evaluate hydration in POEMS syndrome

Capacitive-Coupling Impedance Spectroscopy Using a Non-Sinusoidal Oscillator and Discrete-Time Fourier Transform: An Introductory Study

In this study, we propose a new short-time impedance spectroscopy method with the following three features: (1) A frequency spectrum of complex impedance for the measured object can be obtained even when the measuring electrodes are capacitively coupled with the object and the precise capacitance of the coupling is unknown; (2) the spectrum can be obtained from only one cycle of the non-sinusoidal oscillation waveform without sweeping the oscillation frequency; and (3) a front-end measuring circuit can be built, simply and cheaply, without the need for a digital-to-analog (D-A) converter to synthesize elaborate waveforms comprising multiple frequencies. We built the measurement circuit using the proposed method and then measured the complex impedance spectra of 18 resistive elements connected in series with one of three respective capacitive couplings. With this method, each element's resistance and each coupling's capacitance were estimated independently and compared with their nominal values. When the coupling capacitance was set to 10 nF or 1.0 nF, estimated errors for the resistive elements in the range of 2.0-10.0 kΩ were less than 5%.

Bioelectrical impedance vector analysis and phase angle in boys with Duchenne muscular dystrophy

Background

Duchenne muscular dystrophy (DMD) is a disease characterized by progressive loss of functional muscle mass followed by changes in body composition.

Objective

This study aimed to describe and evaluate bioimpedance parameters in boys with DMD.

Design

This cross-sectional, descriptive study investigated children and adolescents diagnosed with DMD. Age, weight, height, resistance, and reactance data were collected. Phase angle and bioelectrical impedance vector analysis were calculated based on resistance and reactance values.

Results

We analyzed 43 boys aged between 2.7 and 19.8 years. Low-phase angle values were observed during the investigation of bioimpedance parameters. Bioelectrical impedance vector analysis showed that approximately 87% of the subjects presented vectors outside the tolerance ellipses, and only one patient presented vectors located within the 50% tolerance ellipse, indicating normally hydrated and a good body cell mass. Compared with the reference population, boys with DMD had lower levels of body cell mass.

Conclusion

Based on the evidence, compared with the reference population, patients with DMD had lower levels of body cell mass. This evidence points to bioimpedance parameters as useful tools for the nutritional evaluation and clinical management of patients with DMD.

Bioelectrical impedance analysis for monitoring cancer patients receiving chemotherapy and home parenteral nutrition

BACKGROUND

Home parenteral nutrition (HPN) can improve survival, quality of life, nutritional and functional status in cancer patients. Bioelectrical impedance analysis (BIA) is a non-invasive, validated method to assess body composition. The objective of this prospective single-arm study was to investigate the impact of HPN in advanced cancer patients receiving chemotherapy assessed by BIA, clinical and laboratory measures.

METHODS

Adult malnourished cancer outpatients with solid tumors receiving anticancer treatments who were candidates for daily HPN were enrolled. Patients were assessed at baseline (T0), 60 (T1) and 90 days (T2) after HPN start. Assessments included anthropometric and clinical-oncological characteristics, performance status, inflammatory response and Patient-Generated Subjective Global Assessment (PG-SGA).

RESULTS

Sixty-five advanced cancer patients were enrolled. Median overall survival was 317 days. Body weight, BMI, oral calorie and protein intake increased over time (P < 0.01). At T2 the proportion of well-nourished patients, Karnofsky performance status and modified Glasgow prognostic score were improved (P < 0.01), total body water was reduced (P = 0.04), and fat mass increased (P = 0.04). Reactance, resistance and phase angle were significantly associated with survival at T0, T1, and T2, respectively. At T2, PG-SGA category A was a predictor of survival (P < 0.0001).

CONCLUSIONS

After 90 days of HPN, patients experienced significantly improved nutritional status, performance status, prognostic score and some BIA measures. HPN may be an important therapy in oncology patients receiving chemotherapy. Longitudinal use of BIA may help track the effects of HPN and disease progression, potentially contributing to optimal global patient management.

The Association of Hydration Status with Physical Signs, Symptoms and Survival in Advanced Cancer-The Use of Bioelectrical Impedance Vector Analysis (BIVA) Technology to Evaluate Fluid Volume in Palliative Care: An Observational Study

BACKGROUND

Hydration in advanced cancer is a controversial area; however, current hydration assessments methods are poorly developed. Bioelectrical impedance vector analysis (BIVA) is an accurate hydration tool; however its application in advanced cancer has not been explored. This study used BIVA to evaluate hydration status in advanced cancer to examine the association of fluid status with symptoms, physical signs, renal biochemical measures and survival.

MATERIALS AND METHODS

An observational study of 90 adults with advanced cancer receiving care in a UK specialist palliative care inpatient unit was conducted. Hydration status was assessed using BIVA in addition to assessments of symptoms, physical signs, performance status, renal biochemical measures, oral fluid intake and medications. The association of clinical variables with hydration was evaluated using regression analysis. A survival analysis was conducted to examine the influence of hydration status and renal failure.

RESULTS

The hydration status of participants was normal in 43 (47.8%), 'more hydrated' in 37 (41.1%) and 'less hydrated' in 10 (11.1%). Lower hydration was associated with increased symptom intensity (Beta = -0.29, p = 0.04) and higher scores for physical signs associated with dehydration (Beta = 10.94, p = 0.02). Higher hydration was associated with oedema (Beta = 2.55, p<0.001). Median survival was statistically significantly shorter in 'less hydrated' patients (44 vs. 68 days; p = 0.049) and in pre-renal failure (44 vs. 100 days; p = 0.003).

CONCLUSIONS

In advanced cancer, hydration status was associated with clinical signs and symptoms. Hydration status and pre-renal failure were independent predictors of survival. Further studies can establish the utility of BIVA as a standardised hydration assessment tool and explore its potential research application, in order to inform the clinical management of fluid balance in patients with advanced cancer.