Bioimpedance Analysis: A Guide to Simple Design and Implementation

Aroom, Kevin R.; Harting, Matthew T.; Cox, Charles S.; Radharkrishnan, Ravi S.; Smith, Carter; Gill, Brijesh S.

doi:10.1016/j.jss.2008.04.019

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Volume 153, Issue 1 , Pages 23-30, 1 May 2009

Bioimpedance Analysis: A Guide to Simple Design and Implementation

Kevin R. Aroom, M.S.
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas
Matthew T. Harting, M.D.
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas
Charles S. Cox Jr., M.D.
- Department of Pediatric Surgery, University of Texas Health Science Center at Houston, Houston, Texas
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas
Ravi S. Radharkrishnan, M.D.
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas
Carter Smith, M.D.
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas
Brijesh S. Gill, M.D.
- Department of Surgery, University of Texas Health Science Center at Houston, Houston, Texas
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas
- To whom correspondence and reprint requests should be addressed at Department of Surgery, University of Texas–Houston, 6431 Fannin St., MSB 4.268, Houston, TX 77030

Received 17 December 2007 published online 12 May 2008.

Background

Bioimpedance analysis has found utility in many fields of medical research, yet instrumentation can be expensive and/or complicated to build. Advancements in electronic component design and equipment allow for simple bioimpedance analysis using equipment now commonly found in an engineering lab, combined with a few components exclusive to impedance analysis.

Materials and methods

A modified Howland bridge circuit was designed on a small circuit board with connections for power and bioimpedance probes. A programmable function generator and an oscilloscope were connected to a laptop computer and were tasked to drive and receive data from the circuit. The software then parsed the received data and inserted it into a spreadsheet for subsequent data analysis. The circuit was validated by testing its current output over a range of frequencies and comparing measured values of impedance across a test circuit to expected values.

Results

The system was validated over frequencies between 1 and 100 kHz. Maximum fluctuation in current was on the order of micro-Amperes. Similarly, the measured value of impedance in a test circuit followed the pattern of actual impedance over the range of frequencies measured.

Conclusions

Contemporary generation electronic measurement equipment provides adequate levels of connectivity and programmability to rapidly measure and record data for bioimpedance research. These components allow for the rapid development of a simple but accurate bioimpedance measurement system that can be assembled by individuals with limited knowledge of electronics or programming.

Key Words: Bioimpedance, Instrumentation, Current source, Design