Document Detail

Influence of neurally adjusted ventilatory assist and positive end-expiratory pressure on breathing pattern in rabbits with acute lung injury.
MedLine Citation:
PMID:  16957635     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To evaluate the influence of neurally adjusted ventilatory assist (NAVA) and positive end-expiratory pressure (PEEP) on the control of breathing in rabbits with acute lung injury. DESIGN: Prospective animal study. SETTING: Experimental laboratory in a university hospital. SUBJECTS: Male White New Zealand rabbits (n = 18). INTERVENTION: Spontaneously breathing rabbits with hydrochloric acid-induced lung injury were ventilated with NAVA and underwent changes in NAVA gain and PEEP (six nonvagotomized and five vagotomized). Seven other nonvagotomized rabbits underwent 4 hrs of ventilation with hourly titration of PEEP, Fio2, and NAVA gain. MEASUREMENTS AND MAIN RESULTS: We studied diaphragm electrical activity, respiratory pressures, and breathing pattern. After lung injury, 0 cm H2O of PEEP resulted in high tonic and no discernible phasic diaphragm electrical activity in the nonvagotomized rabbits; stepwise increases in PEEP (up to 11.7 +/- 2.6 cm H2O) reduced tonic but increased phasic diaphragm electrical activity. Increasing the NAVA gain reduced phasic diaphragm electrical activity to almost half and abolished esophageal pressure swings. Tidal volume remained at 4-5 mL/kg, and respiratory rate did not change. In the vagotomized group, lung injury did not induce tonic activity, and phasic activity and tidal volume were several times higher than in the nonvagotomized rabbits. Four hours of breathing with NAVA restored breathing pattern and neural and mechanical breathing efforts to pre-lung injury levels. CONCLUSIONS: Acute lung injury can cause a vagally mediated atypical diaphragm activation pattern in spontaneously breathing rabbits. Modulation of PEEP facilitates development of phasic diaphragm electrical activity, whereupon implementation of NAVA can efficiently maintain unloading of the respiratory muscles without delivering excessive tidal volume in rabbits with intact vagal function.
Jean-Christophe Allo; Jennifer C Beck; Lukas Brander; Fabrice Brunet; Arthur S Slutsky; Christer A Sinderby
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Critical care medicine     Volume:  34     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2006-11-28     Completed Date:  2006-12-26     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2997-3004     Citation Subset:  AIM; IM    
Service d'Acceuil et de Traitement des Urgences, Hôpital Cochin, Paris, France.
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MeSH Terms
Diaphragm / innervation,  physiopathology
Hydrochloric Acid
Positive-Pressure Respiration
Respiration, Artificial / methods*
Respiratory Distress Syndrome, Adult / etiology,  physiopathology,  therapy*
Tidal Volume
Grant Support
1 R21 HD45047-01/HD/NICHD NIH HHS
Reg. No./Substance:
7647-01-0/Hydrochloric Acid
Comment In:
Crit Care Med. 2006 Dec;34(12):3055-6   [PMID:  17130707 ]

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

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