Document Detail

Positive end-expiratory pressure delays the progression of lung injury during ventilator strategies involving high airway pressure and lung overdistention.
MedLine Citation:
PMID:  12847394     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: Many studies have investigated the protective role of positive end-expiratory pressure (PEEP) on ventilator-induced lung injury. Most assessed lung injury in protocols involving different ventilation strategies applied for the same length of time. This study, however, set out to investigate the protective role of PEEP with respect to the time needed to reach similar levels of lung injury. DESIGN: Prospective, randomized laboratory animal investigation. SETTING: The University Laboratory of Ospedale Maggiore, Milano, IRCCS. SUBJECTS: Anesthetized, paralyzed, and mechanically ventilated Sprague-Dawley rats. INTERVENTIONS: Three groups of five Sprague-Dawley rats were ventilated using zero end-expiratory pressure ZEEP (PEEP of 0 cm H(2)O) and PEEP of 3 and 6 cm H(2)O and a similar index of lung overdistension (Paw(p)/P(100) congruent with 1.1; where Paw(p) is peak airway pressure and P(100) is the pressure corresponding to total lung capacity). To obtain this, tidal volume was reduced depending on the PEEP. To reach similar levels of lung injury, we measured respiratory system elastance while ventilating the animals and killed them when respiratory system elastance was 150% of baseline. Once target respiratory system elastance was reached, the lung wet-to-dry ratio was obtained. RESULTS: Rats were ventilated with comparable high airway pressure (Paw(p) of 42.8 +/- 3.1, 43.5 +/- 2.6, and 46.2 +/- 4.4, respectively, for PEEP 0, 3, and 6) obtaining similar overdistension (Paw(p)/P(100) - index of overdistension: 1.17 +/- 0.2, 1.06 +/- 0.1, and 1.19 +/- 0.2). The respiratory system elastance target was reached and wet-to-dry ratio was not different in the three groups, suggesting a similar degree of lung damage. The time taken to achieve the target respiratory system elastance was three times longer with PEEP 3 and 6 (55 +/- 14 mins and 60 +/- 17) as compared with zero end-expiratory pressure (18 +/- 3 mins, p <.001). CONCLUSION: These findings confirm that PEEP is protective against ventilator-induced lung injury and may enable the clinician to "buy time" in the progression of lung injury.
Franco Valenza; Massimiliano Guglielmi; Manuela Irace; Giuliana Anna Porro; Silvio Sibilla; Luciano Gattinoni
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Critical care medicine     Volume:  31     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-08     Completed Date:  2003-08-12     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1993-8     Citation Subset:  AIM; IM    
Istituto di Anestesia e Rianimazione, Ospedale Maggiore di Milano, Italy.
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MeSH Terms
Air Pressure*
Barotrauma / physiopathology*,  prevention & control
Disease Progression
Lung / physiopathology
Lung Compliance / physiology*
Lung Injury*
Organ Size / physiology
Positive-Pressure Respiration*
Pulmonary Edema / physiopathology*,  prevention & control
Rats, Sprague-Dawley
Respiration, Artificial / adverse effects*
Respiratory Distress Syndrome, Adult / physiopathology,  prevention & control
Tidal Volume / physiology

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

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