NBCRNA Anesthesia Equipment and Technology 2

Question 1

Pulse oximetry measures oxygen saturation using which principle?

Accepted Answer

Differential light absorption by oxyhemoglobin and deoxyhemoglobin

Answer

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.

Question 2

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

Accepted Answer

Carboxyhemoglobin absorbs light similarly to oxyhemoglobin at 660 nm

Answer

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

Question 3

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

Accepted Answer

Fresh gas flow to the patient end

Answer

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.

Question 4

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

Accepted Answer

Splits gas flow between a bypass chamber and a vaporizing chamber

Answer

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.

Question 5

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

Accepted Answer

30 mL

Answer

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.

NBCRNA - National Board of Certification and Recertification for Nurse Anesthetists Practice Test

NBCRNA - National Board of Certification and Recertification for Nurse Anesthetists Practice Test

NBCRNA Anesthesia Equipment and Technology 2