Correct Answer: B

Rationale: When assessing a client with a history of left-sided heart failure, the presence of bilateral lung crackles is a key finding to determine if the condition is currently active. Crackles in the lungs indicate fluid accumulation, a common sign of left-sided heart failure due to pulmonary congestion.

Correct Answer: B

Rationale: When a client with CAD experiences chest pain, it indicates myocardial ischemia. The nurse should have the client stop the activity and lie back down in bed to reduce the heart's oxygen demand, decrease myocardial workload, and prevent further ischemia. This action helps in improving blood flow to the heart and can potentially alleviate the chest pain.

Correct Answer: C

Rationale: After cardiac catheterization via the femoral vessel, it is crucial to keep the head of the bed elevated no more than 15 degrees to prevent bleeding at the access site. This position helps maintain pressure on the femoral artery, reducing the risk of bleeding and complications post-procedure.

Correct Answer: C

Rationale: In a client with coronary artery disease (CAD), ensuring the availability of oxygen and a flowmeter at the bedside is crucial. Oxygen is essential for adequate oxygenation, which helps prevent myocardial ischemia, a common complication in CAD.

Correct Answer: B

Rationale: ST-segment depression can indicate hypokalemia, affecting the heart's electrical conduction. Hypokalemia leads to alterations in the repolarization phase of the cardiac action potential, resulting in ST-segment depression on the ECG.