Faculty Collaboration Database

An implantable impedance pneumograph monitor for detection of diaphragm contraction and airway obstruction during diaphragm pacing. Med Biol Eng Comput 1999 Mar;37(2):162-8

Date

07/09/1999

Pubmed ID

10396819

DOI

10.1007/BF02513283

Scopus ID

2-s2.0-0032998229 (requires institutional sign-in at Scopus site)   1 Citation

Abstract

Impedance pneumography signals were characterised during diaphragm pacing using stimulating and recording electrodes placed on the abdominal surface of the diaphragm. These measurements were useful for the detection of muscle contraction without confounding effects from stimulus artifacts. Impedance pneumography signals were measured using 23 epimysial electrodes implanted in seven dogs with 1-5 experiments on each electrode. The polarity of the change in impedance associated with diaphragm pacing differed for each recording electrode and its configuration. Thirty-four of 57 cases produced increased impedance, 11 produced decreased impedance and the remaining 12 depended on the level of diaphragm activation. Impedance pneumography signals were useful for detecting complete airway obstruction. The mean difference between the impedance measured during open and obstructed airway conditions was 80% of the open airway impedance signal. The difference between open and obstructed airway impedance measurements was a mean of 2.3 times larger with a recording electrode on the same hemidiaphragm as the stimulating electrode, compared to an electrode placed on the opposite hemidiaphragm (p < 0.05, paired t test, four dogs). In addition, the differences between open and completely obstructed airways were a mean of 2.8 times larger when the second recording electrode was placed on the thorax at the fifth intercostal space, compared to the ninth intercostal space (p < 0.05, two-factor ANOVA, one dog, two replicates). It was concluded that impedance pneumograph circuitry could be incorporated into an existing diaphragm pacer using electrodes placed on the diaphragm to provide valuable measurements of the function of the device.

Author List

Schmit BD, Kayyali H, Makovos B, Mortimer JT

Author

Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University

MESH terms used to index this publication - Major topics in bold

Airway Obstruction
Animals
Diaphragm
Dogs
Electric Impedance
Electric Stimulation
Electrodes, Implanted
Monitoring, Physiologic
Muscle Contraction