Document Detail

Regional lung volume changes during high-frequency oscillatory ventilation.
MedLine Citation:
PMID:  20595820     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To investigate regional lung volume changes occurring during an inflation-deflation maneuver using high-frequency oscillatory ventilation.
DESIGN: Prospective animal trial.
SETTING: Animal research laboratory.
SUBJECTS: Six Yorkshire swine.
INTERVENTIONS: Electrical impedance tomography was used to quantify regional ventilation during high-frequency oscillatory ventilation. The electrical impedance tomography-derived center of ventilation was used to describe the distribution of regional ventilation, whereas spectral analysis was used to describe regional ventilation-induced impedance changes. Lung injury was induced using surfactant lavage. Animals were transitioned to high-frequency oscillatory ventilation and a slow inflation-deflation maneuver was performed by changing mean airway pressure by 5 cm H2O every 15 mins to a maximum mean airway pressure of 40 cm H2O.
MEASUREMENTS AND MAIN RESULTS: The induction of lung injury was associated with a significant shift of the center of ventilation toward nondependent areas and an increase in shunt fraction (p < .001). During the following inflation-deflation maneuver using high-frequency oscillatory ventilation, inflation was associated with a shift of the center of ventilation from nondependent to dependent areas. Center of ventilation was significantly correlated with the shunt fraction (p < .001). Analyzing different lung layers along the gravitational axis separately, nondependent lung areas showed significantly decreased regional ventilation-induced impedance changes at higher pressures, suggesting overdistension, whereas dependent lung areas showed increased impedance changes, suggesting recruitment. The reverse was observed during deflation (all p < .05).
CONCLUSIONS: The center of ventilation during high-frequency oscillatory ventilation correlated with oxygenating efficiency as measured by the shunt fraction. Lung recruitment during high-frequency oscillatory ventilation produced a significant shift of regional ventilation toward dependent areas of the lung and led to overdistension of nondependent areas.
Gerhard K Wolf; Bartłomiej Grychtol; Inez Frerichs; David Zurakowski; John H Arnold
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies     Volume:  11     ISSN:  1529-7535     ISO Abbreviation:  Pediatr Crit Care Med     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-08     Completed Date:  2011-01-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954653     Medline TA:  Pediatr Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  610-5     Citation Subset:  IM    
Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA.
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MeSH Terms
Disease Models, Animal
Electric Impedance
High-Frequency Ventilation*
Lung Volume Measurements
Ventilator-Induced Lung Injury / physiopathology*
Comment In:
Pediatr Crit Care Med. 2010 Sep;11(5):639-40   [PMID:  20823742 ]

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

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