Which instrument measures cylinder pressure in an anesthesia gas delivery system?

• A. Bourdon pressure gauge
• B. Flowmeter
• C. Digital pressure sensor
• D. Pressure relief valve

Answer: (A)

The Bourdon pressure gauge is used to measure cylinder pressure. It relies on a curved tube that tends to straighten as pressure inside increases; that deformation moves a gear and dial pointer, giving a direct readout of the gas cylinder’s pressure. This measurement is crucial in anesthesia gas delivery to know how much gas remains and to ensure pressures stay within safe limits. Flowmeters, while essential for setting and measuring the rate of gas flow to the patient, do not indicate cylinder pressure. A digital pressure sensor can provide pressure readings, but the traditional and most common instrument for this purpose in anesthesia machines is the Bourdon gauge. A pressure relief valve, meanwhile, is a safety feature that releases gas to prevent overpressure and does not measure pressure.