Document Detail


Neurally adjusted ventilatory assist increases respiratory variability and complexity in acute respiratory failure.
MedLine Citation:
PMID:  20179505     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Neurally adjusted ventilatory assist (NAVA) is a partial ventilatory support mode where positive pressure is provided in relation to diaphragmatic electrical activity (EAdi). Central inspiratory activity is normally not monotonous, but it demonstrates short-term variability and complexity. The authors reasoned that NAVA should produce a more "natural" or variable breathing pattern than other modes. This study compared respiratory variability and complexity during pressure support ventilation (PSV) and NAVA. METHODS: Flow and EAdi were recorded during routine PSV (tidal volume approximately 6-8 ml/kg) and four NAVA levels (1-4 cm H2O/microVEAdi) in 12 intubated patients. Breath-by-breath variability of flow and EAdi-related variables was quantified by the coefficient of variation (CV) and autocorrelation analysis. Complexity of flow and EAdi was described using noise titration, largest Lyapunov exponent, Kolmogorov-Sinai entropy, and three-dimensional phase portraits. RESULTS: Switching from PSV to NAVA increased the CV and decreased the autocorrelation for most flow-related variables in a dose-dependent manner (P < 0.05, partial eta for the CV of mean inspiratory flow 0.642). The changes were less marked for EAdi. A positive noise limit was consistently found for flow and EAdi. Largest Lyapunov exponent and Kolmogorov-Sinai entropy for flow were greater during NAVA than PSV and increased with NAVA level (P < 0.05, partial eta 0.334 and 0.312, respectively). Largest Lyapunov exponent and Kolmogorov-Sinai entropy for EAdi were not influenced by ventilator mode. CONCLUSIONS: Compared with PSV, NAVA increases the breathing pattern variability and complexity of flow, whereas the complexity of EAdi is unchanged. Whether this improves clinical outcomes remains to be determined.
Authors:
Matthieu Schmidt; Alexandre Demoule; Christophe Cracco; Alexandre Gharbi; Marie-No?lle Fiamma; Christian Straus; Alexandre Duguet; Stewart B Gottfried; Thomas Similowski
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  112     ISSN:  1528-1175     ISO Abbreviation:  Anesthesiology     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-24     Completed Date:  2010-03-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  670-81     Citation Subset:  AIM; IM    
Affiliation:
Assistance Publique-H?pitaux de Paris, Service de Pneumologie et R?animation, Groupe Hospitalier Piti?-Salp?tri?re, and Universit? Paris 6-Pierre et Marie Curie, Paris, France.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aged, 80 and over
Air Pressure
Blood Gas Analysis
Data Interpretation, Statistical
Diaphragm / physiology
Dose-Response Relationship, Drug
Electromyography*
Entropy
Esophagus / innervation,  physiology
Female
Humans
Intensive Care
Male
Middle Aged
Respiration, Artificial*
Respiratory Distress Syndrome, Adult / physiopathology*,  therapy*
Respiratory Mechanics / physiology*
Ventilator Weaning

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


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