Which inhalant gas can be used in combination with isoflurane?

• A. Nitrous oxide
• B. Diethyl ether
• C. Sevoflurane
• D. Nitrogen

Answer: (A)

Using an adjunct inhalant gas with isoflurane lets you achieve anesthesia while lowering how much isoflurane you need; it also can add analgesia. Nitrous oxide is the classic adjunct because it provides analgesia and has very rapid onset and offset due to its low blood-gas solubility. When used with isoflurane, it reduces the required concentration of the primary volatile agent (MAC-sparing), helping to maintain anesthesia with potentially smoother recovery. The other options aren’t used in the same way: diethyl ether is an antiquated, highly flammable agent not used with modern protocols; sevoflurane is a separate inhalant anesthetic rather than an additive to isoflurane; and nitrogen is not an anesthetic and would merely dilute oxygen, not provide anesthesia.