A client that is unconscious, because of a suspected benzodiazepine overdose, arrives at the emergency department (ED). Which intervention should the nurse prepare to implement first?

The primary life-threatening complication of a benzodiazepine overdose is respiratory depression, which can lead to hypoxia and arrest; therefore, assessing and supporting the client's airway, breathing, and circulation is the immediate priority. While cardiac monitoring (B) is important, it follows ensuring adequate respiration. Seizure precautions (A) are not the primary concern, as benzodiazepines are anticonvulsants. Gastric lavage (C) is rarely used and is contraindicated in a client with a depressed level of consciousness due to the high risk of aspiration.