Evaluation of respiratory acidosis

Last reviewed: 10 Jun 2025
Last updated: 08 Jul 2025

Summary

Differentials

Common

  • COPD
  • Multilobar pneumonia
  • Foreign body aspiration
  • Drug use (narcotics, alcohol, sedatives, anesthetics)
  • Oxygen therapy in COPD
  • CNS infarction or hemorrhage
  • Head trauma
  • CNS infection
  • Hypoventilation syndrome in obesity
  • Pleural effusion
  • Pneumothorax
  • Obesity
  • Kyphoscoliosis
  • Hypokalemia
  • Hypophosphatemia
  • Inadequate mechanical ventilation
Full details

Uncommon

  • Cardiogenic pulmonary edema
  • Acute lung injury/acute respiratory distress syndrome
  • Pulmonary fibrosis
  • Status asthmaticus
  • Laryngospasm
  • Angioedema
  • Primary alveolar hypoventilation
  • Empyema
  • Hemothorax
  • Flail chest
  • Scleroderma
  • Ankylosing spondylitis
  • Fibrothorax
  • Hypothyroidism
  • Paralytic agents and organophosphates
  • High cord trauma/lesions (above C4)
  • Guillain-Barre syndrome
  • Multiple sclerosis
  • Myasthenia gravis
  • Muscular dystrophy
  • Amyotrophic lateral sclerosis
  • Polymyositis and dermatomyositis
  • Phrenic nerve trauma
  • Tetanus
  • Botulism
  • Poliomyelitis
  • Sepsis
  • Fever/malignant hyperthermia
  • Insufflation of CO₂ into body cavity (e.g., laparoscopic surgery)
Full details

Contributors

Authors

Rajiv Dhand, MD

Professor of Medicine

Department of Medicine

University of Tennessee Graduate School of Medicine

Knoxville

TN

Disclosures

RD declares that he has received grants/contracts from Mylan/Theravance and Viatris. RD receives royalties from UpToDate and Taylor and Francis. RD has been a consultant for Verona Pharma and is a member of the American Association for Respiratory Care Clinical Practice Guidelines for Aerosol Therapy. RD has received drugs from Theravance and Viatris for research in clinical trials.

Ghassan Jamal Wadi, MBBS

Pulmonary and Critical care fellow

Department of Medicine

University of Tennessee Graduate School of Medicine

Knoxville

TN

Disclosures

GJW declares that he has no competing interests.

Acknowledgements

Dr Rajiv Dhand and Dr Ghassan Jamal Wadi would like to gratefully acknowledge Dr M. Bradley Drummond and Dr Eddy Fan, previous contributors to this topic.

Disclosures

MBD declares that he has no competing interests. EF has received fees from MC3 Cardiopulmonary and ALung Technologies, Baxter, Getinge, Inspire, Vasomune, and Zoll Medical.

Peer reviewers

Guy Soo Hoo, MD, MPH

Director

Intensive Care Unit

West Los Angeles VA Healthcare Center

Clinical Professor of Medicine

Geffen School of Medicine

UCLA

Los Angeles

CA

Disclosures

GSH declares that he has no competing interests.

Harman Paintal, MBBS

Division of Pulmonary and Critical Care Medicine

Veterans Affairs Palo Alto Health Care System (VAPAHCS)

Palo Alto

CA

Disclosures

HP declares that he has no competing interests.

Patrick J. Neligan, MA, MB BCh, FCARCSI, FJFICM

Consultant in Anaesthesia and Intensive Care

Galway University Hospitals

Senior Lecturer in Anaesthesia

National University of Ireland

Galway Department of Anaesthesia and Intensive Care

University College Hospitals

Galway

Ireland

Disclosures

Not disclosed.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

British Thoracic Society. BTS guideline for oxygen use in adults in healthcare and emergency settings. May 2017 [internet publication].Full text

British Thoracic Society. BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults. Mar 2016 [internet publication].Full text

Global Initiative for Chronic Obstructive Lung Disease. ​Global strategy for prevention, diagnosis and management of COPD: 2025 report​. 2024 [internet publication].Full text

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

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