Anesthetic Equipment and Safety Flashcards

Which component of the anesthesia machine is responsible for reducing cylinder pressure from approximately 2000 psi to a safe working pressure of around 45 psi?

Answer: Pressure regulator (reducing valve)

The pressure regulator (reducing valve) steps down high cylinder pressure to a safe, consistent working pressure of approximately 45 psi for use in the machine.

A patient breathing circuit shows persistently elevated CO2 on capnography despite adequate fresh gas flow. The MOST likely cause is:

Answer: Exhausted CO2 absorbent

Exhausted CO2 absorbent loses its capacity to neutralize exhaled CO2, leading to rebreathing and elevated inspired CO2 on capnography.

When using a Bain circuit (Mapleson D modification), the recommended fresh gas flow for spontaneously breathing adult patients is approximately:

Answer: 2–3 times minute ventilation

For spontaneous ventilation with a Bain circuit, fresh gas flows of 2–3 times the minute ventilation (~150–200 mL/kg/min) are required to prevent rebreathing.

The Pin Index Safety System (PISS) on gas cylinders is designed to:

Answer: Prevent accidental connection of wrong gas cylinders to yokes

PISS uses unique pin configurations for each gas to prevent incorrect cylinders from being mounted on the wrong yoke connection.

During anesthesia machine checkout, the 'oxygen flush valve' is tested. What pressure does activating this valve deliver oxygen at?

Answer: 35–75 psi

The oxygen flush valve delivers oxygen directly from pipeline supply at 35–75 psi, bypassing the flowmeters and vaporizer.

A rotameter (Thorpe tube) in an anesthesia machine is calibrated for a specific gas because flow readings depend on:

Answer: Gas density and viscosity

Rotameter readings depend on the physical properties (density and viscosity) of the gas, so each flowmeter tube is gas-specific and cannot be interchanged.

In a circle breathing system, the purpose of the unidirectional (one-way) valves is to:

Answer: Ensure gas flows in one direction, separating inspiratory and expiratory limbs

Unidirectional valves in a circle system ensure that gas flows only in the correct direction, keeping fresh gas and exhaled gas separated to prevent rebreathing.