ABG Temperature Correction — FRCA Primary MCQ
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Correct answer: B — Blood gas analysers measure at 37°C and hypothermic patients have different in vivo values
Blood gas analysers heat the sample to 37°C for measurement. In hypothermic patients the in vivo PaO2 and PaCO2 are lower than measured values (gas solubility increases as temperature decreases). The alpha-stat approach uses uncorrected (37°C) values. The pH-stat approach corrects to actual patient temperature. Alpha-stat is generally preferred for adult cardiac surgery.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment