Blood Gases

Blood gases are really commonly used in ED, Critical Care, Respiratory Medicine and Prehospitally. In fact, you’d do well to walk 10 meters in an ED without being given one to sign off! But it’s for good reason, because they give you additional information about what’s going on from a respiratory and metabolic perspective in the patient.

And it’s probably worth mentioning at this point, this episode is going to be pretty ‘science-heavy’, there should be something in here for everyone; from the clinician that’s been looking at these things for the last 30 years, to those that haven’t started interpreting gases.

So arterial blood gases can tell you about the efficacy of the patients ventilation in terms of their partial pressures of oxygen and carbon dioxide levels and also from a metabolic perspective about other disorders of their acid-base balance. 

We’ll be referring to the following equation throughout the episode;

In the episode we’ll be covering the following;

-Overview of blood gases

-Respiratory & metabolic sides of the gas



-Bicarbonate or base excess?



-Anion gaps

-System of interpretation

-Venous gases

-Clinical application & examples of interpretation

Once you’ve listened to the podcast make sure you run through the quiz below to consolidate the concepts covered with some more gas examples and of course get you free CPD certificate for your TheResusRoom portfolio!

Once again we’d love to hear any comments or questions either via the website or social media.


Simon, Rob & James

Now that you have listened to the podcast, start the quiz to add it to your CPD Diary

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Understanding base excess (BE): merits and pitfalls. Langer. Intensive Care Med. 2022

Assessing and interpreting arterial blood gases and acid-base balance. Williams. BMJ. 1998

Peripheral venous and arterial blood gas analysis in adults: are they comparable? A systematic review and meta-analysis. Byrne. Respirology. 2014

Agreement between mathematically arterialised venous versus arterial blood gas values in patients undergoing non-invasive ventilation: a cohort study. Kelly. Emerg Med J. 2014

Current Status of Bicarbonate in CKD. Dobre. J Am Soc Nephrol. 2015

Correlation of End-Tidal Carbon Dioxide with Arterial Carbon Dioxide in Mechanically Ventilated Patients. Razi. Archives of Trauma Research

Arterial Blood Gas. Castro. Stats Pearls. 2022

Arterial Bloos Gas; LITFL

Anion Gap; LITFL

PaO2-FiO2 ratio; LITFL

Base Excess vs Standard Base Excess; LITFL

Bicarbonate Buffer System; Wikipedia

Henderson-Hasselbach Equation; Wikipedia

Teaching The Basics Blood Gases; RCEMLearning

Arterial Blood Gas Interpretation; RCEMLearning

Blood Gas Analysis and Pulse Oximetry; ALS Chapter 15

Course Content


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