skip to main content

Oxygen cylinder pressure — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

EasyPhysics and Clinical MeasurementOxygen cylinder pressureFRCA Primary

During transfer, an oxygen cylinder pressure gauge falls steadily as the cylinder is used. Which statement best explains the gauge behaviour?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Cylinder pressure reflects remaining gas for oxygen

Oxygen is stored as a compressed gas in cylinders, so pressure falls broadly in proportion to contents as it is used. The fixed-pressure behaviour applies to gases stored partly as liquid, such as nitrous oxide. Cooling would reduce pressure, not raise it. This is why oxygen cylinder duration can be estimated from pressure and flow.

Reference: Dorsch and Dorsch Understanding Anesthesia Equipment; RCoA Primary FRCA Syllabus