For which of the following patients is nitrous oxide/oxygen analgesia not usually recommended?

Nitrous oxide/oxygen analgesia is typically not recommended for patients with respiratory issues because the method relies on effective ventilation and the ability to breathe comfortably. Conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other significant respiratory impairments can make it difficult for these patients to adequately metabolize and eliminate nitrous oxide. If their respiratory function is compromised, there is a risk that the patient may experience hypoxia or other complications during sedation.

In contrast, nitrous oxide is generally beneficial for patients with anxiety, as it can help alleviate their stress and make procedures more comfortable. It can also be used for patients undergoing routine dental check-ups or minor procedures, as these scenarios typically involve lower levels of sedation and do not impose significant risks when nitrous oxide is managed properly.