Acute respiratory failure

Last reviewed: 3 Jun 2022
Last updated: 30 Mar 2022

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • direct trauma to the thorax and neck
  • dyspnoea
  • confusion
  • tachypnoea
  • accessory breathing muscle use
  • stridor
  • inability to speak
  • retraction of intercostal spaces
  • cyanosis
  • loss of airway/gag reflex
More key diagnostic factors

Other diagnostic factors

  • anxiety
  • headache
  • hypoventilation
  • cardiac rhythm disturbances
  • underlying neuromuscular disorder
  • drug use
  • seizure
  • coma
  • asterixis
  • papilloedema
Other diagnostic factors

Risk factors

  • cigarette smoking
  • young age
  • older age
  • pulmonary infection
  • chronic lung disease
  • upper airway obstruction
  • lower airway obstruction
  • alveolar abnormalities
  • perfusion abnormalities
  • cardiac failure
  • peripheral nerve abnormalities
  • muscle system abnormalities
  • opioid and sedative medicines
  • toxic fumes and gases
  • traumatic spinal injury
  • traumatic thoracic injury
  • central nervous system (CNS) disorders
  • acute vascular occlusion
  • pulmonary effusion
  • pneumothorax
  • hypercoagulable states
More risk factors

Diagnostic investigations

1st investigations to order

  • pulse oximetry
  • arterial blood gases
More 1st investigations to order

Investigations to consider

  • FBC
  • D-dimer
  • serum bicarbonate (HCO₃)
  • ECG
  • chest x-ray
  • pulmonary function tests
  • Urine or serum toxicology
  • chest CT
  • CT pulmonary angiography (CTPA)
  • ventilation/perfusion lung scan
  • capnometry
  • cardiothoracic ultrasound
More investigations to consider

Emerging tests

  • transcutaneous CO₂ monitoring

Treatment algorithm

ACUTE

airway obstruction

no acute upper airway obstruction: stable

no acute upper airway obstruction: unstable

Contributors

Authors

Samuel J. Stratton, MD, MPH
Samuel J. Stratton

Professor

Fielding School of Public Health

David Geffen School of Medicine at UCLA

Los Angeles

Deputy Health Officer

Orange County Health Care Agency

Health Disaster Management/Emergency Medical Services

Santa Ana

CA

Disclosures

SJS declares that he has no competing interests.

Peer reviewers

C. Michael Roberts, MA, MD, FRCP

Consultant Physician

Barts Health

London

UK

Disclosures

CMR declares that he has no competing interests.

Ken Miller, MD, PhD

University of California

Irvine and Orange County Fire Authority

Irvine

CA

Disclosures

KM declares that he has no competing interests.

Christopher Kahn, MD, MPH

Assistant Professor of Clinical Emergency Medicine

Department of Emergency Medicine

University of California

Irvine and Orange County Fire Authority

Irvine

CA

Disclosures

CK declares that he has no competing interests.

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