This third and final webinar in the blood gases series provides a comprehensive overview of blood gas measurement techniques, their clinical interpretation, and appropriate use in diagnosing and managing respiratory and acid–base disorders. It emphasises that correct interpretation depends on understanding each method’s strengths, limitations, and clinical context.
Invasive methods include arterial blood gases (ABG), the gold standard for assessing oxygenation, ventilation, and acid–base balance, but associated with pain and potential complications. Capillary blood gases (CBG), when properly arterialised, are reliable for PCO₂ but not for PO₂. Venous blood gases (VBG) are easy to obtain and useful for estimating pH and bicarbonate, particularly in initial assessments, while mixed venous gases are mainly used for oxygen consumption calculations.
Non-invasive techniques include pulse oximetry, which accurately measures oxygen saturation but not ventilation, and transcutaneous oxycapnometry, which enables continuous monitoring of CO₂ and oxygenation and is especially valuable for detecting nocturnal hypoventilation.
The webinar highlights that blood gases are diagnostic tools—not diagnoses in themselves—and represent only snapshots in time. Accurate interpretation requires clinical context, awareness of potential errors, and complementary data, especially in complex or evolving clinical scenarios.
