Anesthesia Equipment and Technology Flashcards

Pulse oximetry measures oxygen saturation using which principle?

Answer: Differential light absorption by oxyhemoglobin and deoxyhemoglobin

Pulse oximetry uses two wavelengths of light (660 nm red and 940 nm infrared) and Beer-Lambert law to calculate the ratio of oxyhemoglobin to total hemoglobin.

Which condition can cause falsely elevated pulse oximetry readings in a patient with carbon monoxide poisoning?

Answer: Carboxyhemoglobin absorbs light similarly to oxyhemoglobin at 660 nm

Standard pulse oximeters cannot distinguish carboxyhemoglobin from oxyhemoglobin because both absorb red light (660 nm) similarly, leading to falsely high SpO2 readings.

The Bain circuit (Mapleson D modification) is a co-axial design where the inner tube carries what?

Answer: Fresh gas flow to the patient end

In the Bain circuit, the inner tube delivers fresh gas to the patient end while exhaled gases travel through the outer corrugated tube to the APL valve.

The anesthesia vaporizer is classified as variable bypass because it does what?

Answer: Splits gas flow between a bypass chamber and a vaporizing chamber

Variable bypass vaporizers split the fresh gas stream — a portion passes through the vaporizing chamber to become saturated with vapor, while the rest bypasses it; the ratio determines the output concentration.

When using a laryngeal mask airway (LMA), what is the maximum recommended cuff inflation volume for a size 4 LMA?

Answer: 30 mL

The size 4 LMA (for adults 50–70 kg) has a maximum recommended cuff inflation volume of 30 mL to achieve a proper seal without excessive pressure.

The Venturi effect in anesthesia equipment is used primarily in which device?

Answer: Venturi oxygen mask to entrain room air

Venturi (air-entrainment) oxygen masks use the Bernoulli/Venturi principle to entrain precise amounts of room air, delivering accurate fixed FiO2 concentrations.