Summary
Definition
History and exam
Key diagnostic factors
- low oxygen saturation
- acute respiratory failure
Other diagnostic factors
- critically ill patient
- dyspnea
- increased respiratory rate
- pulmonary crepitations
- low lung compliance
- fever, cough, pleuritic chest pain
- frothy sputum
Risk factors
- sepsis
- aspiration
- pneumonia
- severe trauma
- blood transfusions
- lung transplantation
- pancreatitis
- history of alcohol misuse
- burns and smoke inhalation
- drowning
- e-cigarette and vaping product use
- drug overdose
- cigarette smoking
Diagnostic investigations
1st investigations to order
- chest x-ray
- arterial blood gases
- sputum culture
- blood culture
- urine culture
- amylase and lipase
Investigations to consider
- brain natriuretic peptide (BNP)
- echocardiogram
- pulmonary artery catheterization
- bronchoalveolar lavage or endotracheal aspirate
- CT scan of the thorax
- viral testing
- open lung biopsy
Treatment algorithm
all patients
Contributors
Authors
Lorraine Ware, MD

Professor of Medicine and Pathology, Microbiology and Immunology
Director
Vanderbilt Medical Scholars Program
Division of Allergy, Pulmonary and Critical Care Medicine
Department of Medicine
Vanderbilt University School of Medicine
Nashville
TN
Disclosures
LW has received research contract support from CSL Behring, Boehringer Ingelheim and Genentech. She has received consulting fees and/or scientific advisory board fees from CSL Behring, Merck, Foresee, Citius, and Boehringer Ingelheim.
Acknowledgements
Dr Lorraine Ware would like to gratefully acknowledge Dr Richard Fremont, a previous contributor to this topic.
Disclosures
RF declares that he has no competing interests.
Peer reviewers
Michael A. Matthay, MD
Director of Medicine Critical Care Fellowship
Department of Anesthesia and Perioperative Care
University of California San Francisco
CA
Disclosures
MAM declares that he has no competing interests.
Timothy Evans, MBBS
Professor of Intensive Care Medicine
Royal Brompton Hospital
London
UK
Disclosures
TE declares that he has no competing interests.
Differentials
- Coronavirus disease 2019 (COVID-19)
- Acute heart failure
- Bilateral pneumonia
More DifferentialsGuidelines
- Symptom assessment for mechanically ventilated patients: principles and priorities
- Guidelines on the management of acute respiratory distress syndrome
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