O₂ Cylinder Duration — Modern Anesthesia

Cylinder

Presets are a starting point — the two fields decide every number below.

Size

Full contents L

Full-cylinder pressure psi

Presets: StatPearls NBK513350 · OpenAnesthesia, Medical Gas Systems · Ehrenwerth, Anesthesia Equipment · Srivastava, Indian J Anaesth 2013.

Size letters differ between standards — a British-standard D holds 340 L, not 425 L. Type in what the cylinder label says.

BOC Healthcare, Medical gas cylinder data chart.

Gauge and flow

Pressure unit

Gauge pressure psi

Flow L/min

Remaining

Contents remaining—L

Enter the gauge pressure

Duration at set flow—

Enter the gauge pressure and a flow

Fraction of a full cylinder—

Contents fall linearly with gauge pressure — Boyle's law, contents = full contents × gauge ÷ full pressure. Not valid for nitrous oxide, which is stored as a liquid.

Srivastava, Indian J Anaesth 2013;57(5):500–506.

bedside check: E at 1000 psi, 10 L/min = 660 × 1000 ÷ 2000 = 330 L = 33 min

Margins and checks

Usable down to a 25% reserve—

Enter the gauge pressure and a flow

Gauge pressure at that reserve—

Duration at double the flow—

Duration is inversely proportional to flow, so doubling the flow halves it

The 25% reserve is a planning convention for when to swap, not a published threshold.

Intensive Care Society & FICM, Transfer of the Critically Ill Adult, 5th ed, 2026 — plan 2 × (flow × transfer time).

MHRA, Care and handling of oxygen cylinders and their regulators, 2013.