 Personnel experienced in direct laryngoscopy are not always immediately available in certain settings that require emergency tracheal intubation . For this reason , specialized devices have been designed to act as bridges to a definitive airway . Such devices include the laryngeal mask airway , cuffed oropharyngeal airway and the esophageal @-@ tracheal <unk> ( <unk> ) . Other devices such as rigid stylets , the <unk> ( a blind technique ) and indirect fiberoptic rigid stylets , such as the Bullard scope , Upsher scope and the <unk> can also be used as alternatives to direct laryngoscopy . Each of these devices have its own unique set of benefits and drawbacks , and none of them is effective under all circumstances . 
