Document Detail

Electrical impedance tomography can monitor dynamic hyperinflation in dogs.
MedLine Citation:
PMID:  9475886     Owner:  NLM     Status:  MEDLINE    
We assessed in eight dogs the accuracy with which electrical impedance tomography (EIT) can monitor changes in lung volume by comparing the changes in mean lung conductivity obtained with EIT to changes in esophageal pressure (Pes) and to airway opening pressure (Pao) measured after airway occlusion. The average volume measurement errors were determined: 26 ml for EIT; 35 ml for Pao; and 54 ml for Pes. Subsequently, lung inflation due to applied positive end-expiratory pressure was measured by EIT (delta VEIT) and Pao (delta VPAO) under both inflation and deflation conditions. Whereas delta VPAO was equal under both conditions, delta VEIT was 28 ml greater during deflation than inflation, indicating that EIT is sensitive to lung volume history. The average inflation delta VEIT was 67.7 +/- 78 ml greater than delta VPAO, for an average volume increase of 418 ml. Lung inflation due to external expiratory resistance was measured during ventilation by EIT (delta VEIT,vent) and Pes (delta VPes,vent) and at occlusion by EIT (delta VEIT,occl), Pes, and Pao. The average differences between EIT estimates and delta VEIT,occl were 5.8 +/- 44 ml for delta VEIT,vent and 49.5 +/- 34 ml for delta VEIT,occl. The average volume increase for all dogs was 442.2 ml. These results show that EIT can provide usefully accurate estimates of changes in lung volume over an extended time period and that the technique has promise as a means of conveniently and noninvasively monitoring lung hyperinflation.
A Adler; N Shinozuka; Y Berthiaume; R Guardo; J H Bates
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  84     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-03-24     Completed Date:  1998-03-24     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  726-32     Citation Subset:  IM    
Meakins-Christie Laboratories, McGill University, Montreal, Qeubec, Canada.
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MeSH Terms
Airway Resistance / physiology
Electric Impedance
Esophagus / physiology
Lung Volume Measurements
Monitoring, Physiologic / instrumentation,  methods*
Positive-Pressure Respiration / adverse effects*
Respiratory Mechanics / physiology*
Tomography / methods

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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