A patient with signs and symptoms of myasthenia gravis is scheduled to receive Tensilon (edrophonium chloride) for diagnostic purposes. Which of the following assessments should the nurse prioritize before administering this medication to assess the effectiveness of Tensilon?

Rationale: A. While it is important to review the patient’s medications to avoid drug interactions (e.g., with cholinergic or anticholinergic drugs), this is not the primary assessment to evaluate Tensilon’s effectiveness in diagnosing myasthenia gravis. B. Respiratory status is critical to monitor due to the risk of respiratory compromise in myasthenia gravis or during a cholinergic crisis. However, prior to administering Tensilon for diagnostic purposes, the primary goal is to assess neuromuscular response, not respiratory function, although baseline respiratory assessment is part of overall safety. C. Monitoring vital signs is necessary because edrophonium can cause bradycardia or hypotension, but these parameters do not measure the diagnostic effectiveness of the medication. D. Tensilon works by temporarily inhibiting acetylcholinesterase, increasing acetylcholine at the neuromuscular junction. The diagnostic response is evaluated by observing improvement in muscle strength and endurance, typically in areas such as ptosis, facial muscles, or grip strength. Comparing pre- and post-administration muscle performance allows the nurse and provider to determine whether the patient has myasthenia gravis.