Which of the following is NOT an adverse effect of using nitrous oxide?

Decreased heart rate is not commonly recognized as an adverse effect of nitrous oxide. In fact, nitrous oxide is typically associated with effects such as mild sedation and analgesia, which can lead to a sense of relaxation rather than a significant drop in heart rate. The anesthetic properties of nitrous oxide can cause some hemodynamic stability, especially when administered in appropriate doses, leading to an expectation of normal or increased heart rate in many clinical scenarios.

On the other hand, nausea, hallucinations, and hypoxia are known adverse effects associated with nitrous oxide. Nausea can occur in some patients after administration, particularly if they are sensitive to the agent. Hallucinations, although rare, can happen on occasion, particularly at higher concentrations or in individuals with certain vulnerabilities. Hypoxia is a significant concern when nitrous oxide is used, as it can displace oxygen, leading to decreased oxygen levels in the blood if not administered with supplemental oxygen. Thus, understanding these aspects of nitrous oxide helps clarify why decreased heart rate does not belong to the list of its adverse effects.