Document Detail


Analysis of atelectasis, ventilated, and hyperinflated lung during mechanical ventilation by dynamic CT.
MedLine Citation:
PMID:  16304344     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY OBJECTIVE: To study the dynamics of lung compartments by dynamic CT (dCT) imaging during uninterrupted pressure-controlled ventilation (PCV) and different positive end-expiratory pressure (PEEP) settings in healthy and damaged lungs. DESIGN: Experimental animal investigation. SETTING: Experimental animal facility of a university department. INTERVENTIONS: In seven anesthetized pigs, static inspiratory pressure volume curves were obtained to identify the individual lower inflection point (LIP) before and after saline solution lung lavage. During PCV, PEEP was adjusted 5 millibars (mbar) below the individually determined LIP (LIP - 5), at the LIP, and 5 mbar above the LIP (LIP + 5). MEASUREMENTS AND RESULTS: Measurements were repeated before and after induction of lung damage. Hemodynamics, arterial and mixed venous blood gases, and dCT imaging in one juxtadiaphragmatic slice (effective temporal resolution of 100 ms) were assessed during uninterrupted PCV in series of three successive respiratory cycles. The mean fractional area (FA) of the hyperinflated lung (FA-H), mean FA of ventilated lung, mean FA of poorly ventilated lung, and mean FA of nonventilated lung (FA-NV), and the change in FA of the whole lung area (DeltaFA) were compared at different PEEP settings. Calculated pulmonary shunt (Qs/Qt) was compared to FA-NV. LIP + 5 decreased the amount of atelectasis (FA-NV) and increased hyperinflation (FA-H) in healthy and injured lungs. Cyclic changes of atelectasis (DeltaFA-NV) and hyperinflation (DeltaFA-H) were observed in both healthy and injured lungs. In the injured but not in the healthy lungs, the amount of cyclic changes of atelectasis and hyperinflation were independent from the adjusted PEEP level. FA-NV correlated with the calculated Qs/Qt, with a slight overestimation (mean +/- SEM, 2.1 +/- 4.1%). CONCLUSIONS: dCT imaging allows the following: (1) the quantification of the extent of atelectasis, ventilated, poorly ventilated, and hyperinflated lung parenchyma during ongoing mechanical ventilation; (2) the detection and quantification of repeated recruitment and derecruitment, as well as hyperinflation; and (3) an estimation of Qs/Qt. dCT adds promising functional information for the respiratory treatment of early ARDS.
Authors:
Matthias David; Jens Karmrodt; Carsten Bletz; Sybil David; Annette Herweling; Hans-Ulrich Kauczor; Klaus Markstaller
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Chest     Volume:  128     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-11-23     Completed Date:  2005-12-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3757-70     Citation Subset:  AIM; IM    
Affiliation:
Department of Anesthesiology, Johannes Gutenberg-University, Mainz, Germany. david@mail.uni-mainz.de
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MeSH Terms
Descriptor/Qualifier:
Animals
Carbon Dioxide
Hemodynamics
Image Processing, Computer-Assisted
Irrigation
Lung / physiopathology
Oxygen
Positive-Pressure Respiration
Pulmonary Alveoli / physiopathology
Pulmonary Atelectasis / physiopathology
Pulmonary Gas Exchange
Respiration, Artificial*
Respiratory Distress Syndrome, Adult
Swine
Tidal Volume
Tomography, X-Ray Computed / methods*
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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


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