Document Detail

Lung recruitment during small tidal volume ventilation allows minimal positive end-expiratory pressure without augmenting lung injury.
MedLine Citation:
PMID:  10507622     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Ventilation with positive end-expiratory pressure (PEEP) above the inflection point (P(inf)) has been shown to reduce lung injury by recruiting previously closed alveolar regions; however, it carries the risk of hyperinflating the lungs. The present study examined the hypothesis that a new strategy of recruiting the lung with a sustained inflation (SI), followed by ventilation with small tidal volumes, would allow the maintenance of low PEEP levels (<P(inf)) without inducing additional lung injury. DESIGN: Prospective, randomized, controlled ex vivo study. SETTING: An animal laboratory in a university setting. SUBJECTS: Isolated nonperfused lungs of adult Sprague-Dawley rats. INTERVENTIONS: We studied the effect on compliance and lung injury in four groups (n = 10 per group) of lavaged rat lungs. One group (group 1) served as a control; their lungs were inflated at PEEP < P(inf) but not ventilated. The other three groups were ventilated with small tidal volumes (5 to 6 mL/kg) for 2 hrs with the following interventions: group 2, PEEP < P(inf) without SI; group 3, PEEP < P(inf) after a SI to 30 cm H2O for 30 secs; and group 4, PEEP > P(inf). MEASUREMENTS AND MAIN RESULTS: In groups 2 and 4, static compliance decreased after ventilation (p < .01). Histologically, group 2 (PEEP < P(inf) without SI) showed significantly greater injury of small airways, but not of terminal respiratory units, compared with group 1. Group 3 (PEEP < P(inf) after a SI), but not group 4, showed significantly less injury of small airways and terminal respiratory units compared with group 2. CONCLUSIONS: We conclude that small tidal volume ventilation after a recruitment maneuver allows ventilation on the deflation limb of the pressure/volume curve of the lungs at a PEEP < P(inf). This strategy a) minimizes lung injury as well as, or better than, use of PEEP > P(inf), and b) ensures a lower PEEP, which may minimize the detrimental consequences of high lung volume ventilation.
P C Rimensberger; G Pristine; B M Mullen; P N Cox; A S Slutsky
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Critical care medicine     Volume:  27     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  1999 Sep 
Date Detail:
Created Date:  1999-10-15     Completed Date:  1999-10-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1940-5     Citation Subset:  AIM; IM    
Department of Critical Care, The Hospital for Sick Children, University of Toronto, Ontario, Canada.
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MeSH Terms
Analysis of Variance
Intermittent Positive-Pressure Ventilation / methods*
Lung Compliance
Positive-Pressure Respiration
Prospective Studies
Random Allocation
Rats, Sprague-Dawley
Respiratory Distress Syndrome, Adult / pathology,  therapy*
Respiratory Mechanics*
Total Lung Capacity
Comment In:
Crit Care Med. 2001 Apr;29(4):915   [PMID:  11373501 ]

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