Document Detail

Effects of inspiratory pause on CO2 elimination and arterial PCO2 in acute lung injury.
MedLine Citation:
PMID:  18801962     Owner:  NLM     Status:  MEDLINE    
A high respiratory rate associated with the use of small tidal volumes, recommended for acute lung injury (ALI), shortens time for gas diffusion in the alveoli. This may decrease CO(2) elimination. We hypothesized that a postinspiratory pause could enhance CO(2) elimination and reduce Pa(CO(2)) by reducing dead space in ALI. In 15 mechanically ventilated patients with ALI and hypercapnia, a 20% postinspiratory pause (Tp20) was applied during a period of 30 min between two ventilation periods without postinspiratory pause (Tp0). Other parameters were kept unchanged. The single breath test for CO(2) was recorded every 5 min to measure tidal CO(2) elimination (VtCO(2)), airway dead space (V(Daw)), and slope of the alveolar plateau. Pa(O(2)), Pa(CO(2)), and physiological and alveolar dead space (V(Dphys), V(Dalv)) were determined at the end of each 30-min period. The postinspiratory pause, 0.7 +/- 0.2 s, induced on average <0.5 cmH(2)O of intrinsic positive end-expiratory pressure (PEEP). During Tp20, VtCO(2) increased immediately by 28 +/- 10% (14 +/- 5 ml per breath compared with 11 +/- 4 for Tp0) and then decreased without reaching the initial value within 30 min. The addition of a postinspiratory pause significantly decreased V(Daw) by 14% and V(Dphys) by 11% with no change in V(Dalv). During Tp20, the slope of the alveolar plateau initially fell to 65 +/- 10% of baseline value and continued to decrease. Tp20 induced a 10 +/- 3% decrease in Pa(CO(2)) at 30 min (from 55 +/- 10 to 49 +/- 9 mmHg, P < 0.001) with no significant variation in Pa(O(2)). Postinspiratory pause has a significant influence on CO(2) elimination when small tidal volumes are used during mechanical ventilation for ALI.
Jérôme Devaquet; Björn Jonson; Lisbet Niklason; Anne-Gaëlle Si Larbi; Leif Uttman; Jérôme Aboab; Laurent Brochard
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-09-18
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  105     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-12-03     Completed Date:  2009-02-06     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:  1944-9     Citation Subset:  IM    
Medical Intensive Care Unit, AP-HP, INSERM Unit 841, Centre Hospitalier Albert Chenevier-Henri Mondor, Créteil, France.
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MeSH Terms
Aged, 80 and over
Blood Gas Analysis
Carbon Dioxide / blood*,  metabolism*
Lung Diseases / metabolism*,  physiopathology*
Middle Aged
Pneumonia / metabolism,  physiopathology
Positive-Pressure Respiration
Respiration, Artificial
Respiratory Dead Space / physiology
Respiratory Distress Syndrome, Adult / metabolism,  physiopathology
Respiratory Mechanics / physiology*
Tidal Volume / physiology
Reg. No./Substance:
124-38-9/Carbon Dioxide

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

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