Impedance to transthoracic direct current discharge: A model for testing interface material

G. A. Ewy, D. Taren

Research output: Contribution to journalConference articlepeer-review

18 Scopus citations


An in vitro method for screening the relative impedance of gels has been developed. A nonconductive chamber was built with 1-cm-diameter electrodes placed 1 cm apart. This chamber is filled with electrode gel to be tested. The defibrillator used delivers a half-sinusoidal waveform. When the same stored energy is discharged by this defibrillator into increasing impedance, the resultant delivered current wave decreases while the voltage wave increases. Thus, with increasing impedance, the delivered volt-time interval increases. Twelve electrode gels were studied; 10 measurements were made on each gel. There is a marked variation in the impedance to direct current discharge of commercially available electrode gels. A large number of commercially available electrode gels are not suitable for use as the interface between the paddle electrodes and the chest wall during elective cardioversion and emergency defibrillation.

Original languageEnglish (US)
Pages (from-to)47-48
Number of pages2
JournalMedical Instrumentation
Issue number1
StatePublished - Jan 1978
EventPurdue Card Defibrillation Conf, 2nd, Proc - Lafayette, LA, USA
Duration: Sep 19 1977Sep 21 1977

ASJC Scopus subject areas

  • Bioengineering
  • Medicine (miscellaneous)


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