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Identification of pH Disturbances on the ABG

In this course, you will learn how to recognize and categorize acid-base disturbances detected on the arterial blood gas (ABG). You will learn how values measured on a venous blood gas (VBG) compare to those reported on the ABG.

1.0 x AMA PRA Category 1 Credits™
Available on the Pro Plan



Based on the underlying causative mechanism, acid-base disturbances are divided into one of four categories. In this course, we teach you a simple method to recognise and categorize acid-base disturbances detected on the arterial blood gas (ABG).  We explain the meaning of the terminology used in this field. We explain the definition of ‘metabolic’ acid-base disturbances and ‘respiratory’ acid-base disturbances. We teach you how to distinguish between metabolic and respiratory pH disorders. In the quiz, we give you the opportunity to apply what you have learned to clinical cases. In recent years, the venous blood gas (VBG) has emerged as a useful alternative to the ABG in the management of metabolic disorders. We teach you how values relevant to pH disturbances reported on a VBG compare to values measured on an ABG.


Planner and Author: Dr John Seery MB PhD

  • Consultant Physician at St. Vincent's University Hospital, Dublin, Ireland
  • Lecturer at the School of Medicine and Medical Science, University College Dublin, Ireland
  • Studied medicine at the University of Cambridge, United Kingdom
  • A Natural Sciences graduate of Trinity College Dublin, Ireland
  • PhD in Cell Biology from University College London, United Kingdom

Planner: Dr Karen Strahan PhD (University of Cambridge), Head of Editorial
Planner: Tommy O'Sullivan, CME Manager

Estimated Time to Complete

1.0 hours

Target Audience

  • Physicians
  • Nurses
  • Nurse Practitioners
  • Physician Assistants
  • Paramedics

Learning Objectives

Upon successful completion of this activity, you will be able to:

  • Explain the difference between metabolic and respiratory pH disturbances on the ABG
  • Identify and categorize acid-base disturbances on the ABG
  • Use appropriate terminology in the description of an acid-base disturbance on the ABG
  • Identify clinical situations in which a VBG can be used in place of an ABG to analyse an acid-base disturbance
  • Interpret the clinical significance of the acid-base related parameters reported on a VBG

Course Content

  • Introduction
  • Important Terminology in pH Disturbances
  • Acids & Bases
  • Acids & Bases in the Body
  • Identification of pH Disturbances
  • Two Important Caveats
  • Too Simple?
  • Quiz
  • Essential Reading

Release date


Expiration date


Instructions for Participation

Participants must complete the online activity during the valid period as noted above.
Follow these steps:

  1. View videos in sequence
  2. Read the papers on the essential reading list
  3. Complete the quiz
  4. Complete the activity evaluation form to provide feedback for continuing education purposes and for the development of future activities
  5. Download the Certificate of Completion

Relevant Financial Disclosures

Acadoodle adheres to the ACCME's Standards for Integrity and Independence in Accredited Continuing Education. Any individuals in a position to control the content of a CE activity, including faculty, planners, reviewers or others are required to disclose all relevant financial relationships with ineligible entities (commercial interests). All relevant conflicts of interest have been mitigated prior to the commencement of the activity.

Planners and faculty for this activity have no relevant financial relationships with commercial interests to disclose.


Seery JP and Ryan J. 10 Things You Need to Know about Arterial Blood Gas (ABG): Identifying Simple pH Disturbances.

Seery JP and Ryan J. How to Read a Venous Blood Gas.

Menchine M et al. Diagnostic Accuracy of Venous Blood Gas Electrolytes in the Emergency Department. Acad Emerg Med. 2011;18:1105-8.

Rutledge TE. Acid-base disturbances in the emergency department. Part 1: Piecing the clues together. Can Fam Physician. 1991. 37:2254 – 8.

Additional Reading

Leader DP. A method of introducing the physiological carbon-dioxide bicarbonate buffer system to medical students. Biochem Edu. 1979;7(2):37-8.

Hills AG. pH and the Henderson-Hasselbach Equation. Am J Med. 1973;55:131-133.

Hamilton PK et al. Understanding Acid-base Disorders. Ulster Med J. 2017;86(3):161-6.

ACCME Accreditation Statement

Acadoodle, Ltd is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Credit Designation Statement

AMA Physician’s Recognition Award

Acadoodle, Ltd designates this enduring material activity for a maximum of 1.0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

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