NBCRNA Anesthesia Equipment and Technology

Question 1

On the anesthesia machine, the fail-safe valve is designed to prevent the delivery of hypoxic gas mixtures by doing what?

Accepted Answer

Proportionally reducing nitrous oxide flow when oxygen pressure drops

Answer

The fail-safe (oxygen failure protection device) shuts off or proportionally reduces the flow of N2O and other gases when the oxygen supply pressure falls below a threshold.

Question 2

The circle breathing system uses soda lime to do what?

Accepted Answer

Absorb carbon dioxide from exhaled gases

Answer

Soda lime (primarily calcium hydroxide with sodium and potassium hydroxide) absorbs exhaled CO2 through a chemical reaction, allowing low-flow rebreathing circuits.

Question 3

A capnograph waveform showing an elevated baseline (above zero) throughout the respiratory cycle suggests what problem?

Accepted Answer

CO2 rebreathing due to exhausted absorbent

Answer

An elevated baseline on capnography indicates that exhaled CO2 is being rebreathed, most commonly due to exhausted CO2 absorbent or an incompetent expiratory valve.

Question 4

During a pre-use anesthesia machine check, which test verifies that the low-pressure circuit is leak-free?

Accepted Answer

Negative pressure (suction bulb) leak test

Answer

The negative pressure leak test uses a suction bulb to apply negative pressure to the low-pressure circuit; failure to re-expand indicates an intact, leak-free system.

Question 5

What does a sustained upslope (shark fin appearance) in the capnography waveform indicate?

Accepted Answer

Obstructive airway disease or bronchospasm

Answer

A prolonged, slanted upslope on capnography (shark fin) reflects uneven CO2 elimination from lung units with different time constants, characteristic of obstructive disease.

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