Final answer:
The nurse should prioritize the pt complaining of substernal discomfort and take prompt action to assess their condition and inform a healthcare provider.
Step-by-step explanation:
The nurse should immediately prioritize the pt complaining of substernal discomfort. This symptom can be indicative of a heart condition, such as a heart attack. The nurse should assess the pt's vital signs, obtain an EKG, and inform the healthcare provider. Prompt action is necessary to ensure timely intervention and appropriate medical care.