Final answer:
Remove the OPA immediately if an unconscious victim exhibits a gag reflex to prevent potential aspiration and choking.
Step-by-step explanation:
If you have inserted an OPA into the mouth of an unconscious victim who reacts by having a gag reflex, you should remove the airway immediately. The presence of a gag reflex indicates that the victim still has protective airway reflexes and may not tolerate the OPA. Continued attempts to insert the OPA could cause vomit and potentially lead to aspiration. Instead, monitor the victim's airway for any changes and be prepared to use alternative methods to keep the airway open if necessary.