In which medical emergency situation is an oxygen mask provided but not turned on?

In the case of hyperventilation, an oxygen mask is provided to the individual to offer a sense of security; however, it is not turned on because the primary concern in hyperventilation is that the person is already breathing excessively and disrupting their carbon dioxide levels. Turning on the oxygen could exacerbate the condition by increasing the oxygen concentration without addressing the underlying issue of overbreathing. Instead, the individual may be advised to breathe into a paper bag or focus on calming their breaths, which helps restore a normal equilibrium. This approach emphasizes the understanding that while oxygen masks are generally used to assist with breathing issues, in the specific case of hyperventilation, the management focuses on correcting the breathing pattern rather than supplementing oxygen.