A male client with dementia is admitted to the emergency department (ED) because he accidentally self-administered several doses of diltiazem. Which intervention is most important for the nurse to implement?

A. Frequently assess the client’s blood pressure: While monitoring blood pressure is important, it is not as critical as monitoring the ECG in cases of diltiazem overdose. Diltiazem is a calcium channel blocker that can lead to significant cardiac effects. B. Observe the client for signs of gastric irritation: This is relevant for some medications, but in the case of diltiazem overdose, the primary concern is the potential for severe cardiac effects rather than gastric irritation. C. Monitor electrocardiogram (ECG) continuously: Diltiazem overdose can lead to serious cardiac arrhythmias, such as bradycardia, AV block, or other conduction disturbances. Continuous ECG monitoring is crucial to detect these potentially life-threatening complications. D. Assess for changes in level of consciousness: While important, changes in level of consciousness are secondary to the immediate need to monitor cardiac function closely in the context of diltiazem overdose.