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bioimpedance vector analysis (BIVA)
Indications:
- non-invasive, quick & inexpensive technique to estimate body composition, including total body water
- evaluation of heart failure [1]
- assessment of risk for contrast nephropathy [2]
Principle:
- fat-free tissues & fluids are good conductors, while bone & fat tissues are poor conductors
- resistance is inversely related to the total body water
Procedure:
- measures the opposition of body tissues to the flow of an alternating current of 800 micro Amps at an operating frequency of 50 kHz (bioelectrical impedance
- performed with a portable battery-operated device
- subject must be supine with inferior limbs at 45 degrees & superior limbs abducted at 30 degrees to avoid skin contacts with the trunk and with stretcher
- 4 cutaneous electrodes, 2 on wrist & 2 on ipsilateral ankle, are applied with an inter-electrode distance of at least 5 cm to prevent interaction between electrodes
- bioelectrical impedance is measured in about 30 sec
- reference values are adjusted for patient's age, BMI, gender & height
- results are plotted resistance vs reactance* to provide a vector proportional to total body water
* reactance (Xc) is considered proportional to body mass
Related
impedance
General
bioimpedance
analysis
References
- Di Somma S, Vetrone F, Maisel AS
Bioimpedance Vector Analysis (BIVA) for Diagnosis and Management
of Acute Heart Failure.
Curr Emerg Hosp Med Rep (2014) 2: 104
https://link.springer.com/article/10.1007/s40138-014-0043-9
- Maioli M et al.
Bioimpedance-guided hydration for the prevention of contrast-
induced kidney injury: The HYDRA Study.
J Am Coll Cardiol 2018 Jun 26; 71:2880.
PMID: 29929610
- Brar SS.
Protocol-driven CI-AKI prevention in the cath lab.
J Am Coll Cardiol 2018 Jun 26; 71:2890.
PMID: 29929611