Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Bilateral diffuse alveolar infiltrates are present with severe hypoxemia Pulmonary capillary wedge pressure (PCWP) is < 18 mm Hg Arterial partial pressure of oxygen/inspired oxygen concentration (PaO2/FiO2) of ≤ 200 mm Hg +++ GENERAL CONSIDERATIONS ++ Acute respiratory distress syndrome (ARDS) is the most severe form of acute lung injury ARDS may be a manifestation of several conditions, such as sepsis, aspiration, hypertransfusion, toxic inhalation, severe nonthoracic trauma, and cardiopulmonary bypass Other incompletely understood causes include high-altitude pulmonary edema, neurogenic pulmonary edema, narcotic overdose, eclampsia, and cardioversion Clinically, one-third of ARDS patients have sepsis The mechanism of lung injury varies, but the common pathway involves elevated pulmonary capillary pressure resulting in pulmonary endothelial damage with increased capillary permeability +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Tachypnea, dyspnea, labored breathing +++ PHYSICAL EXAM FINDINGS ++ Pulmonary rales Hypoxemia, tachycardia +++ DIFFERENTIAL DIAGNOSIS ++ Cardiogenic pulmonary edema (PCWP is typically > 18 mm Hg) Lymphangitic carcinomatosis (PCWP is < 18 mm Hg) Unilateral pulmonary edema after evacuation of large pleural effusion (PCWP is normal) +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ Blood cultures may be positive in sepsis Plasma B-type natriuretic peptide (BNP) may be used to distinguish heart failure and cardiogenic pulmonary edema from noncardiogenic causes +++ IMAGING STUDIES ++ Chest x-ray: – Shows diffuse patchy bilateral infiltrates initially; then confluence with air bronchograms – The costophrenic angles are spared and effusions are unusual – Heart size is normal Echocardiography: shows normal left ventricular function +++ DIAGNOSTIC PROCEDURES ++ Right heart catheterization may be necessary to exclude cardiogenic shock +++ TREATMENT +++ CARDIOLOGY REFERRAL ++ Suspected cardiogenic shock +++ HOSPITALIZATION CRITERIA ++ All patients with ARDS are hospitalized +++ MEDICATIONS ++ Treat the underlying cause if possible Give supplemental oxygen and noninvasive ventilatory support in early stages of acute lung injury Give mechanical ventilatory support with positive end-expiratory pressure and low tidal volumes (6–10 mL/kg) in established ARDS Novel ventilation strategies, including high-frequency ventilation and liquid ventilation, hold promise for improvement of outcomes +++ THERAPEUTIC PROCEDURES ++ Endotracheal intubation is almost always required +++ MONITORING ++ ECG monitoring in hospital as appropriate Routine right-heart catheter monitoring is not recommended +++ DIET AND ACTIVITY ++ Intensive care unit protocol for parenteral nutrition in the critically ill +++ ONGOING MANAGEMENT +++ HOSPITAL DISCHARGE CRITERIA... Your Access profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth