JOURNAL HOME CME HOME THIS MONTH PAST ISSUES ETOC COLLECTIONS AUTHORS REVIEWERS EDITORIAL BOARD FEEDBACK RSS HELP
		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Tyler, D. C. Articles by Cheney, F. W. Search for Related Content PubMed PubMed Citation Articles by Tyler, D. C. Articles by Cheney, F. W.

Comparison of Positive End-Expiratory Pressure and Inspiratory Positive Pressure Plateau in Ventilation of Rabbits with Experimental Pulmonary Edema

Donald C. Tyler, MD^*, and Frederick W. Cheney, MD

*Assistant Professor of Anesthesiology and Pediatrics. Department of Anesthesiology, RN-10, University of Washington, Seattle, Washington 98195. Professor of Anesthesiology. Department of Anesthesiology, RN-10, University of Washington, Seattle, Washington 98195.

Abstract

We investigated the effects of an inspiratory positive pressure plateau produced by a high (4/ 1) inspiratory-expiratory (I/E) ratio in rabbits with pulmonary edema induced with oleic acid. With an inspiratory pressure plateau, intrapulmonary shunt was significantly reduced compared to a standard 1 /2 I/E ratio. Reduction in shunt was also obtained when positive end-expiratory pressure (PEEP) was added to the 1 /2 I/E ratio ventilatory pattern. Since the improvement in shunt could have been caused by either recruitment of alveoli or by maintenance of lung volume at end exhalation we measured tidal volume and thoracic gas volume to distinguish between the two. With both patterns, improvement in shunt was associated with an increase in thoracic gas volume. The increase in thoracic gas volume was greater with PEEP than with 4/1 for an equivalent increase in mean airway pressure. The results suggest that an inspiratory pressure plateau improves gas exchange in pulmonary edema, but that this improvement occurs because of an increase in end-expiratory lung volume. Positive end-expiratory pressure is a preferable method of increasing end expiratory lung volume because a greater increase occurs for the same change in airway pressure.

Key Words: VENTILATION: positive end-expiratory pressure • VENTILATION: shunting • LUNG: edema

Anesthesia & Analgesia® is published for the International Anesthesia Research Society® by Lippincott Williams & Wilkins with the assistance of Stanford University Libraries' HighWire Press®. Copyright 2006 by the International Anesthesia Research Society. Online ISSN: 1526-7598   Print ISSN: 0003-2999