DAANCE Anesthesia Equipment and Delivery 5 — Questions and Answers
Question 1: Which action should be taken FIRST if a patient's reservoir bag becomes fully deflated during nitrous oxide administration?
- Immediately remove the nasal mask
- Increase total gas flow rate (Correct answer)
- Switch to 100% oxygen
- Check and open the flow control valves
Correct answer: Increase total gas flow rate
A deflated reservoir bag indicates the gas flow rate is insufficient to meet the patient's ventilatory demand; increasing total flow restores the bag volume.
Question 2: In a central piped gas supply system, what color are the nitrous oxide pipeline connections (DISS fittings) in the United States?
- Green
- Blue (Correct answer)
- Gray
- Yellow
Correct answer: Blue
DISS (Diameter Index Safety System) fittings for nitrous oxide pipelines are blue, matching the cylinder color code, to prevent misconnection with oxygen (green).
Question 3: What does the term 'titration' mean in the context of nitrous oxide/oxygen sedation delivery?
- Setting a fixed concentration at the start of the procedure
- Gradually increasing the concentration until the desired sedation level is achieved (Correct answer)
- Mixing equal parts nitrous oxide and oxygen before delivery
- Rapidly delivering a high concentration to speed onset
Correct answer: Gradually increasing the concentration until the desired sedation level is achieved
Titration means incrementally increasing the nitrous oxide concentration in small steps while monitoring patient response to achieve the optimal sedation level safely.
Question 4: After completing a nitrous oxide sedation procedure, what is the recommended minimum duration for administering 100% oxygen before dismissing the patient?
- 1–2 minutes
- 3–5 minutes (Correct answer)
- 8–10 minutes
- 15–20 minutes
Correct answer: 3–5 minutes
A minimum of 3–5 minutes of 100% oxygen is recommended post-procedure to prevent diffusion hypoxia caused by rapid outgassing of nitrous oxide from the bloodstream.
Question 5: Which equipment item is used to measure the percentage of oxygen in a gas mixture delivered by a dental anesthesia machine?
- Capnograph
- Pulse oximeter
- Oxygen analyzer (Correct answer)
- Spirometer
Correct answer: Oxygen analyzer
An oxygen analyzer directly measures the fraction of oxygen in the gas mixture at the machine outlet to verify safe concentration before delivery.
Question 6: A 'minimum oxygen concentration' setting on modern nitrous oxide machines is typically set at no lower than:
- 10%
- 21%
- 30% (Correct answer)
- 50%
Correct answer: 30%
Most dental nitrous oxide units are engineered to deliver no less than 30% oxygen, ensuring a margin of safety above atmospheric oxygen levels (21%) to prevent hypoxia.
Question 7: Which maintenance task should be performed on a nitrous oxide nasal mask between patients to prevent cross-contamination?
- Wiping with a dry cloth only
- Heat sterilization in an autoclave
- Cleaning and disinfecting per manufacturer instructions or using a single-use disposable mask (Correct answer)
- Soaking in water for 10 minutes
Correct answer: Cleaning and disinfecting per manufacturer instructions or using a single-use disposable mask
Nasal masks must be cleaned and disinfected according to manufacturer guidelines between patients, or single-use disposable masks should be used to eliminate cross-contamination risk.
DAANCE Anesthesia Equipment and Delivery 5
Which action should be taken FIRST if a patient's reservoir bag becomes fully deflated during nitrous oxide administration?