Final answer:
The nurse should question administering a beta blocker if the client's BP is < 90/60 mm Hg and monitor for changes in BP and pulse, especially for orthostatic hypotension and bradycardia, when a client is on this medication.
Step-by-step explanation:
When a nurse is administering a beta blocker to a client diagnosed with essential hypertension, the nurse should implement the intervention of questioning the administration of the medication if the client's blood pressure (BP) is lower than 90/60 mm Hg. This is because beta blockers can lower the blood pressure, and administering them when the blood pressure is already low could lead to hypotension. Moreover, since beta blockers can affect heart rate by blocking the beta-1 receptors and thus slowing the heart rate, it is also important for the nurse to monitor the client's BP in different positions (lying, standing, sitting) to assess for orthostatic hypotension, which can be a side effect of beta blockers. The nurse should not administer the medication if the client's radial pulse is significantly high (>100) or too slow, as beta blockers can cause bradycardia. However, a potassium level of 3.8 mEq does not warrant notifying the health care provider (HCP) as it falls within the normal range.