A client with diabetes mellitus type 2 has been well controlled on metformin. The client is scheduled for a magnetic resonance imaging (MRI) scan with contrast. What priority nurse takes at this time?

Choice A reason: Before any procedure involving intravenous contrast, the nurse must assess the client's baseline renal function. Contrast media is nephrotoxic, and metformin is excreted by the kidneys. If renal function is impaired (indicated by elevated BUN or creatinine), the risk of contrast-induced nephropathy and subsequent metformin-associated lactic acidosis increases significantly. Choice B reason: While knowing a patient's medication history is important, antibiotics do not have the same critical interaction with MRI contrast media as metformin does. The priority is identifying risk factors for renal failure or metabolic acidosis, which are directly related to the combination of contrast agents and the patient's current diabetic therapy. Choice C reason: While metformin is generally withheld for 48 hours after the administration of contrast media, the "priority" action before the scan is to assess if the kidneys can handle the contrast in the first place. The decision to withhold the medication is based on the laboratory results obtained during the initial assessment. Choice D reason: Patient education regarding the purpose of the MRI is a standard nursing responsibility, but it is not the priority safety action. Ensuring the patient does not experience acute renal failure or a life-threatening acid-base imbalance due to contrast exposure takes precedence over general procedural teaching.