CAA CAA Equipment & Technology in Anesthesia 1 — Questions and Answers
Question 1: Which component of the anesthesia machine is responsible for reducing high-pressure gas from the cylinder to a lower, usable working pressure?
- Flowmeter
- Pressure regulator (reducing valve) (Correct answer)
- Vaporizer
- Common gas outlet
Correct answer: Pressure regulator (reducing valve)
The pressure regulator reduces high-pressure cylinder gas to a safe working pressure of approximately 45–55 psi for use in the machine.
Question 2: The oxygen flush valve on an anesthesia machine delivers oxygen at approximately what flow rate?
- 2–4 L/min
- 5–8 L/min
- 35–75 L/min (Correct answer)
- 100–150 L/min
Correct answer: 35–75 L/min
The oxygen flush valve bypasses the flowmeters and vaporizer, delivering oxygen at 35–75 L/min directly to the common gas outlet.
Question 3: Which safety feature prevents the administration of a hypoxic gas mixture on a modern anesthesia machine?
- Pin Index Safety System (PISS)
- Oxygen ratio monitor/controller (ORMC) (Correct answer)
- Diameter Index Safety System (DISS)
- Fail-safe valve
Correct answer: Oxygen ratio monitor/controller (ORMC)
The oxygen ratio monitor/controller (ORMC) mechanically links nitrous oxide and oxygen flowmeters to ensure a minimum of 21–25% oxygen in the delivered mixture.
Question 4: In a circle breathing system, the PRIMARY function of the CO2 absorbent is to:
- Remove volatile anesthetic agents
- Absorb exhaled carbon dioxide to allow rebreathing (Correct answer)
- Add humidity to inspired gases
- Filter bacterial contaminants
Correct answer: Absorb exhaled carbon dioxide to allow rebreathing
CO2 absorbent (e.g., soda lime or Amsorb) chemically absorbs exhaled CO2, allowing safe rebreathing and reducing fresh gas requirements.
Question 5: Which anesthesia machine alarm should prompt immediate verification that the oxygen supply has not been interrupted?
- Inspiratory pressure limit alarm
- Oxygen supply low-pressure alarm (Correct answer)
- Tidal volume alarm
- Agent concentration alarm
Correct answer: Oxygen supply low-pressure alarm
The oxygen supply low-pressure alarm activates when pipeline oxygen pressure falls below approximately 30 psi, indicating potential supply failure.
Question 6: The Pin Index Safety System (PISS) is designed to prevent:
- Vaporizer interlock bypass
- Wrong gas cylinder attachment to the yoke (Correct answer)
- Incorrect flowmeter settings
- Soda lime exhaustion
Correct answer: Wrong gas cylinder attachment to the yoke
PISS uses unique pin-hole patterns on cylinder valve stems and yokes to ensure only the correct gas cylinder can be connected to each yoke.
CAA CAA Equipment & Technology in Anesthesia 1
Which component of the anesthesia machine is responsible for reducing high-pressure gas from the cylinder to a lower, usable working pressure?