ABG Direct Measurements — FRCA Primary MCQ

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EasyPhysics & Clinical MeasurementABG Direct MeasurementsFRCA Primary

A blood gas analyser directly measures which three parameters?

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Correct answer: E — pH, PaO2, PaCO2

Direct measurements: pH (glass electrode) / PaCO2 (Severinghaus electrode) / PaO2 (Clark electrode). All other values (HCO3- / base excess / SaO2) are calculated using the Henderson-Hasselbalch equation and oxygen dissociation curve.

Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment