Document Detail


Mechanism of relief of tachypnea during pressure support ventilation.
MedLine Citation:
PMID:  8625685     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Pressure support ventilation (PSV) provides a range of ventilatory support from partial respiratory muscle unloading, where inspiratory work is shared between the patient and the mechanical ventilator, to total respiratory muscle unloading, where inspiratory work is performed solely by the ventilator. This study is designed to determine if minimizing work fully accounts for relief of tachypnea during PSV. We examined respiratory parameters over a range of PSV that includes the crossover from partial to total respiratory muscle unloading. Eight studies were obtained on seven intubated patients in respiratory failure. Ventilation, occlusion pressure (P0.1), and patient inspiratory work (WOBinsp) were measured while PSV was varied. In all patients, WOBinsp decreased as PSV increased. The level of PSV where WOBinsp was minimized was identified; this marked the crossover from partial to total respiratory muscle unloading. Frequency decreased with increasing PSV but remained elevated (range, 22 to 38 breaths/min) at the crossover. Frequency was normalized only at PSV levels 131 to 193% of the levels of pressure at the crossover. Tidal volume (VT) changed little during partial support and averaged 5.9 mL/kg at the crossover. VT increased only on PSV providing total unloading. Six of seven patients exhibited increasing static compliance with increasing VT suggesting alveolar recruitment. P0.1 tracked WOBinsp over the entire range of PSV (r = 0.95, p < 0.001). The normalization of frequency observed above the crossover coincided with increasing VT rather than decreasing work. These observations suggest that reflexes resulting from increased VT and/or alveolar recruitment may have contributed to the normalization of frequency.
Authors:
K I Berger; I B Sorkin; R G Norman; D M Rapoport; R M Goldring
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chest     Volume:  109     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  1996 May 
Date Detail:
Created Date:  1996-06-27     Completed Date:  1996-06-27     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1320-7     Citation Subset:  AIM; IM    
Affiliation:
Division of Pulmonary and Critical Care Medicine, New York University Medical Center, NY 10016, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aged, 80 and over
Female
Humans
Middle Aged
Positive-Pressure Respiration* / methods
Respiration / physiology*
Respiratory Insufficiency / physiopathology,  therapy
Respiratory Mechanics

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


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