Accession Number:

AD0429938

Title:

THORACIC CAGE IMPEDANCE MEASUREMENTS. CANCELLATION OF RESPIRATION EFFECTS ON TRANSTHORACIC IMPEDANCE,

Descriptive Note:

Corporate Author:

MINNESOTA UNIV MINNEAPOLIS

Personal Author(s):

Report Date:

1963-12-01

Pagination or Media Count:

7.0

Abstract:

Monitoring transthoracic electrical imedance related to cardiac activity has been hampered by changes in the measured impedance due to respiration. It is necessary to nullify respiration effects if a relatively undistorted cardiac activity waveform is to be recorded continuously during respiration. Both direct filtering and subraction of the respiration signal from the composite respiration-cardiac waveform were considered. Methods used to obtain a respiration signal for subtraction purposes were based on 1 a chest circumference measurement obtained with a bellows and pressure transducer, 2 the detection of an impedance change due solely to respiration, and 3 the utilization of the phase-angle signal associated with the transthoracic impedance. Promising results were obtained when the phase-angle signal was combined with the composite respiration-cardiac waveform. The effect of repiration impedance change on the resulting waveform was less than 50 of the cardiac activity signal under restingbreathing conditions. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE