CAA CAA Anesthesia Equipment & Technology 1 — Questions and Answers
Question 1: Which component of the anesthesia machine is responsible for reducing high-pressure gas from cylinders to a safe working pressure?
- Flowmeter
- Pressure regulator (Correct answer)
- Vaporizer
- Oxygen flush valve
Correct answer: Pressure regulator
The pressure regulator reduces high cylinder pressure (up to 2200 psi for O2) down to a safe working pressure of approximately 45–55 psi.
Question 2: What is the purpose of the oxygen fail-safe device on an anesthesia machine?
- It increases oxygen flow when nitrous oxide runs low
- It shuts off or proportionally reduces nitrous oxide flow if oxygen pressure drops (Correct answer)
- It triggers an audible alarm when oxygen saturation falls below 90%
- It prevents oxygen from being delivered at flows above 10 L/min
Correct answer: It shuts off or proportionally reduces nitrous oxide flow if oxygen pressure drops
The oxygen fail-safe device automatically shuts off or reduces N2O (and other gases) if oxygen supply pressure falls, preventing hypoxic mixtures.
Question 3: Which type of vaporizer is classified as a 'variable bypass' vaporizer?
- Tec 6 desflurane vaporizer
- Datex-Ohmeda Tec 7 (Correct answer)
- Aladin cassette vaporizer
- Siemens-Elema 950
Correct answer: Datex-Ohmeda Tec 7
The Datex-Ohmeda Tec 7 is a variable bypass vaporizer where a portion of fresh gas flow is diverted through the vaporizing chamber.
Question 4: A circle breathing system's unidirectional valves serve which primary function?
- Humidifying inspired gases
- Ensuring unidirectional gas flow through the circuit (Correct answer)
- Absorbing carbon dioxide from exhaled gas
- Delivering precise volatile anesthetic concentrations
Correct answer: Ensuring unidirectional gas flow through the circuit
Unidirectional (one-way) valves in the circle system ensure exhaled gas flows through the CO2 absorber and fresh gas flows to the patient without mixing.
Question 5: What color change indicates that soda lime CO2 absorbent is exhausted?
- Blue to white
- White to pink/violet (Correct answer)
- Yellow to green
- Green to gray
Correct answer: White to pink/violet
Most soda lime contains an ethyl violet indicator that turns pink/violet when the absorbent is exhausted and can no longer neutralize CO2.
Question 6: Which parameter does a spirometry loop on the anesthesia ventilator monitor display?
- Pressure–time waveform
- Flow–volume loop (Correct answer)
- Capnography waveform
- SpO2 plethysmogram
Correct answer: Flow–volume loop
A spirometry (flow–volume) loop plots flow against tidal volume, helping detect bronchospasm, circuit leaks, and patient–ventilator dyssynchrony.
CAA CAA Anesthesia Equipment & Technology 1
Which component of the anesthesia machine is responsible for reducing high-pressure gas from cylinders to a safe working pressure?