These devices are used for the following: Primary airway management Rescue ventilation when bag-valve-mask ventilation is difficult Rescue ventilation when definitive airway management is expected to be difficult (eg, with anatomic abnormalities) Ventilation when personnel are limited (eg, prehospital) As a conduit for endotracheal intubation The SGAs used most commonly in the operating room are the laryngeal mask airways (LMAs) and similar devices, while other SGAs are used more commonly in the emergency department and for prehospital airway management (see Other Devices).