Capnography Upsloping Plateau — FRCA Final MCQ

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ModerateAirway ManagementCapnography Upsloping PlateauFRCA Final

Capnography develops upsloping Phase III (alveolar plateau) during anaesthesia that wasn't present initially. Most likely cause?

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Reveal the answer and explanation

Correct answer: E — Bronchospasm

Upsloping Phase III = asynchronous alveolar emptying from airway obstruction/bronchospasm. Fast-emptying (low CO2) units followed by slow-emptying (high CO2) obstructed units produce upward slope. Circuit leak = falling baseline; exhausted absorber = rising baseline.

Reference: RCOA – 2020 – Capnography interpretation