Final answer:
The nurse's initial action should be to compare the current vital signs with those on admission.
Step-by-step explanation:
The nurse's initial action should be to compare the current vital signs with those on admission. By comparing the current vital signs with previous measurements, the nurse can determine any changes or abnormalities in the patient's condition. The elevated blood pressure in this case is a cause for concern, as it may indicate uncontrolled hypertension. The low diastolic pressure is also a significant finding and should be assessed further.