Falla respiratoria

aSevere Hypoxemic Respiratory Failure : Part 1 −−Ventilatory Strategies
Adebayo Esan, Dean R. Hess, Suhail Raoof, Liziamma George and Curtis N. Sessler Chest 2010;137;1203-1216 DOI 10.1378/chest.09-2415 The online version of this article, along with updated information and services can be found online on the World Wide Web at: http://chestjournal.chestpubs.org/content/137/5/1203.full.htmlCHEST is the official journal of the American College of Chest Physicians. It has been published monthly since 1935. Copyright 2010 by the American College of Chest Physicians, 3300 Dundee Road, Northbrook, IL 60062. All rights reserved. No part of this article or PDF may be reproduced or distributed without the prior written permission of the copyright holder.(http://chestjournal.chestpubs.org/site/misc/reprints.xhtml) ISSN:0012-3692

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Postgraduate Education Corner
CONTEMPORARY REVIEWS IN CRITICAL CARE MEDICINE

Severe Hypoxemic Respiratory Failure
Part 1—Ventilatory Strategies
Adebayo Esan, MD; Dean R. Hess, PhD, RRT, FCCP; Suhail Raoof, MD, FCCP; Liziamma George, MD, FCCP; and Curtis N. Sessler, MD, FCCP

Approximately 16% of deaths in patients with ARDS results fromrefractory hypoxemia, which is the inability to achieve adequate arterial oxygenation despite high levels of inspired oxygen or the development of barotrauma. A number of ventilator-focused rescue therapies that can be used when conventional mechanical ventilation does not achieve a specific target level of oxygenation are discussed. A literature search was conducted and narrative review written tosummarize the use of high levels of positive end-expiratory pressure, recruitment maneuvers, airway pressure-release ventilation, and high-frequency ventilation. Each therapy reviewed has been reported to improve oxygenation in patients with ARDS. However, none of them have been shown to improve survival when studied in heterogeneous populations of patients with ARDS. Moreover, none of the therapieshas been reported to be superior to another for the goal of improving oxygenation. The goal of improving oxygenation must always be balanced against the risk of further lung injury. The optimal time to initiate rescue therapies, if needed, is within 96 h of the onset of ARDS, a time when alveolar recruitment potential is the greatest. A variety of ventilatory approaches are available to improveoxygenation in the setting of refractory hypoxemia and ARDS. Which, if any, of these approaches should be used is often determined by the availability of equipment and clinician bias. CHEST 2010; 137(5):1203–1216
Abbreviations: ALI 5 acute lung injury; APRV 5 airway pressure-release ventilation; CPAP 5 continuous positive airway pressure; HFOV 5 high-frequency oscillatory ventilation; HFPV 5high-frequency percussive ventilation; IBW 5 ideal body weight; mPaw 5 mean airway pressure; OI 5 oxygenation index; DP 5 pressure amplitude of oscillation; PCIRV 5 pressure-controlled inverse-ratio ventilation; PCV 5 pressure-controlled ventilation; PEEP 5 positive endexpiratory pressure; Pplat 5 plateau pressure; RCT 5 randomized controlled trial; VCV 5 volume-controlled ventilation

lung injury(ALI) and ARDS on the basis of the following clinical parameters: acute onset of severe respiratory distress; bilateral infiltrates on frontal chest radiograph; absence of left atrial hypertension, a pulmonary capillary wedge pressure 18 mm Hg, or no clinical signs of left heart failure; and severe hypoxemia (ALI, PaO2 FIO2 ratio 300 mm Hg; ARDS, PaO2 FIO2 ratio 200 mm Hg). The definition does nottake into consideration, however, the etiology (pulmonary or extrapulmonary) or the level of positive end-expiratory pressure (PEEP) required. More than 80% of patients with ARDS require intubation and mechanical ventilation.2 A lung-protective ventilation strategy should be used with a tidal volume of 4 to 8 mL kg ideal body weight (IBW), a plateau pressure (Pplat) of 30 cm H2O, and modest levels...