Question 15 of 18

Yes - that is correct.

The most likely cause of his headache and feeling of nausea is that he probably did not receive 100% oxygen for a sufficient amount of time after the nitrous oxide was turned off.

In his case, he received nitrous oxide-oxygen for 45 minutes. Therefore, he should receive 100% oxygen for 15 minutes (remember that for every 15 minutes of exposure to nitrous oxide, the patient is to receive 5 minutes of 100% oxygen after the nitrous oxide is turned off).