Skip to Main 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

  • Resolution of ARDS

  • Correction of the underlying problem

FOLLOW-UP

  • Depends on the cause

COMPLICATIONS
...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.