Final answer:
Relative contraindications for blind nasotracheal intubation include nasal obstruction and facial trauma, as they can complicate the procedure or increase risk.
Step-by-step explanation:
The relative contraindications for blind nasotracheal intubation include conditions that may complicate or render the procedure unsafe or inappropriate. Nasal obstruction could impede the passage of the intubation tube through the nasal cavity. Facial trauma might involve fractures or injuries that could be exacerbated by the procedure or lead to further complications. Both of these conditions are considered relative contraindications because they increase the risk associated with blind nasotracheal intubation.
Options such as a reduced level of consciousness and a history of allergies do not classify as relative contraindications specifically for blind nasotracheal intubation per se, but are relevant considerations in the overall assessment and management of the airway and anesthesia.