Final answer:
Nitrous oxide in combination with halogenated inhalational anesthetics decreases the minimum alveolar concentration (MAC) of the anesthetic, effectively enhancing its potency and enabling lower doses to be used, which can increase patient safety.
Step-by-step explanation:
The question pertains to the use of nitrous oxide combined with a halogenated inhalational anesthetic, such as desflurane, isoflurane, or sevoflurane. When used in combination, nitrous oxide can actually decrease the minimum alveolar concentration (MAC) of the halogenated anesthetic. MAC is a measure of an anesthetic's potency - specifically, it's the concentration needed to inhibit movement in 50% of patients exposed to a painful stimulus. So, the correct answer to the question is b: it decreases the MAC.
Nitrous oxide is a potent greenhouse gas and when heated can serve as a strong oxidizing agent. It is often combined with other anesthetics to enhance their effects, allowing for lower doses of the more potent and potentially riskier halogenated agents. This combination strategy also indirectly increases patient safety by using reduced amounts of halogenated anesthetic and their potential side effects.