After inserting a nasopharyngeal airway, how should the casualty be placed?

Placing a casualty in the recovery position after inserting a nasopharyngeal airway is crucial for maintaining an open airway and ensuring the safety of the patient. This position allows for drainage of fluids from the mouth and prevents aspiration, should the person vomit, while also supporting effective airflow.

In the recovery position, the casualty is placed on their side, which helps keep the airway clear and reduces the risk of obstructing the airway with any foreign matter. This position facilitates easier access for monitoring the casualty's breathing and allows for better visualization and management of any potential complications.

The other choices do not promote the same level of safety for maintaining an open airway. A seated position may not provide adequate support for the airway and can lead to choking if the casualty loses consciousness. Placing them on their stomach could obstruct the airway and increase the risk of aspiration, while a supine position without adjustments might lead to airway compromise, especially if the casualty has reduced consciousness. Thus, the recovery position is the most effective and safest way to manage a casualty with an inserted nasopharyngeal airway.