Question 1

Nausea after nitrous oxide exposure may occur as a result of which of the following?&#10;A) Titrating the levels of nitrous oxide delivered&#10;B) Overoxygenating at the end of the appointment&#10;C) Seesawing the nitrous oxide delivery&#10;D) Turning off the nitrous oxide too quickly&#10;E) All of the above

Accepted Answer

Seesawing the nitrous oxide delivery (alternating periods of high and low levels of nitrous oxide) can cause nausea in some patients. Titrating the levels of nitrous oxide and overoxygenating at the end of the appointment are important steps to prevent nausea, and turning off the nitrous oxide too quickly can cause discomfort, but these actions alone may not necessarily cause nausea. Therefore, option C is the best choice as it specifically identifies a potential cause of nausea after nitrous oxide exposure.

Question 2

The immediate treatment for entry into the excitement stage of analgesia is which of the following?&#10;A) Telling the client to breathe through the mouth&#10;B) Immediately increasing the percentage of oxygen to 100%&#10;C) Verbally and physically stimulating the patient&#10;D) Decreasing the nitrous oxide 20% while increasing the oxygen by the same amount&#10;E) A and C only

Accepted Answer

Immediately increasing the percentage of oxygen to 100%

Question 3

The proportion of nitrous oxide the client in question 11 is receiving is which of the following?&#10;A) 20%&#10;B) 30%&#10;C) 40%&#10;D) 50%&#10;E) None of the above

Accepted Answer

According to the information provided in question 11, the client is receiving a nitrous oxide concentration of 3%. As nitrous oxide is commonly mixed with oxygen in dental offices, the remaining 97% must be oxygen. To find out the proportion of nitrous oxide, we can divide the concentration of nitrous oxide by the total concentration of the mixture (nitrous oxide + oxygen). Therefore, 3% nitrous oxide divided by 7% (100% - 93% oxygen) gives a proportion of approximately 0.429, which is equivalent to 42.9% or rounded to 40%. Therefore, the proportion of nitrous oxide the client is receiving is 40%.

Question 4

The flowmeters indicate that a client is receiving 4 L of nitrous oxide and 6 L of oxygen.What is the client's tidal volume?&#10;A) 4 L&#10;B) 6 L&#10;C) 10 L&#10;D) 2 L&#10;E) 7 L

Accepted Answer

The tidal volume is the total volume of gas the client is receiving per breath or per minute (depending on context). In this case, it's the sum of the volumes of nitrous oxide and oxygen, which is 4 L + 6 L = 10 L.

Question 5

After the administration of nitrous oxide-oxygen analgesia,oxygen alone should be given for a minimum of _____ minutes before the patient is released.&#10;A) 1 to 3&#10;B) 5&#10;C) 7 to 8&#10;D) 10&#10;E) 12 to 15

Accepted Answer

When scaling and root planing are completed, the nitrous oxide should be turned off and oxygen increased to maintain the tidal volume. For every 15 minutes of exposure to nitrous oxide, the client must receive 5 minutes of 100% oxygen. If a client is sedated for less than 5 minutes, he or she still should be oxygenated for a minimum of 5 minutes to prevent tissue hypoxia.

Question 6

Oversedation with nitrous oxide may be manifested by which of the following?&#10;A) Loss of consciousness&#10;B) Allergic reaction&#10;C) Tingling sensation&#10;D) A slight heaviness in the patient's chest&#10;E) A and B

Accepted Answer

Oversedation with nitrous oxide can lead to loss of consciousness as it is a central nervous system depressant.

Question 7

The proportion of oxygen the client in question 11 is receiving is which of the following?&#10;A) 10%&#10;B) 20%&#10;C) 30%&#10;D) 50%&#10;E) 60%

Accepted Answer

The proportion of oxygen is determined by dividing the amount of oxygen delivered by the tidal volume.

Question 8

A scavenger system incorporated into the nitrous oxide-oxygen analgesia unit does which of the following?&#10;A) Collects nitrous oxide to be reused&#10;B) Collects oxygen to be remixed into the reservoir bag&#10;C) Takes out nitrous oxide that is exhaled through the mask&#10;D) Monitors the operatory room air&#10;E) A and C

Accepted Answer

A scavenger system in a nitrous oxide-oxygen analgesia unit is designed to remove excess nitrous oxide that is exhaled by the patient through the mask, preventing it from escaping into the surrounding air and potentially affecting the health of the dental staff and other patients.

Question 9

When the proportions of nitrous oxide and oxygen are adjusted to achieve the desired level of analgesia,each adjustment should be at the rate of which of the following?&#10;A) 0.5 L nitrous oxide for at least 30 seconds&#10;B) 0.5 to 1 L nitrous oxide for at least 1 minute&#10;C) 1 L nitrous oxide for at least 30 seconds&#10;D) 1 to 1.5 L nitrous oxide for at least 1 minute&#10;E) 1.5 L nitrous oxide for at least 30 seconds

Accepted Answer

Each adjustment should be made slowly and incrementally, typically at a rate of 0.5 to 1 L of nitrous oxide per minute to achieve the desired level of analgesia.

Deck 40: Nitrous Oxideoxygen Analgesia