Correct Answer: D

Rationale: The correct answer is D. A serum calcium level of 7.8 mg/dL requires immediate intervention due to the risk of hypocalcemia. Hypocalcemia can lead to serious complications such as tetany, seizures, and cardiac arrhythmias. The other laboratory findings are within normal limits or slightly elevated, which do not pose an immediate threat to the client's health in this scenario.

Correct Answer: B

Rationale: The correct instruction is to advise the client to avoid alcohol while taking phenytoin. Alcohol can interact with phenytoin, making it less effective and leading to increased side effects. Taking the medication with meals (Choice A) may help reduce gastrointestinal upset but is not the most crucial instruction for this medication. Limiting sodium intake (Choice C) is not directly related to phenytoin therapy. Taking the medication at bedtime (Choice D) is not a standard instruction for phenytoin administration.

Correct Answer: D

Rationale: The correct answer is 'D - Shortness of breath.' In a client with congestive heart failure experiencing fluid volume overload, shortness of breath is a critical finding that indicates possible pulmonary congestion and worsening heart failure. This symptom requires immediate attention to prevent further complications. Choices A, B, and C are common findings in clients with CHF but are not as urgent as shortness of breath. Weight gain may indicate fluid retention, cough can be due to pulmonary congestion, and edema in lower extremities is a common manifestation of CHF, but none of these findings are as concerning as shortness of breath in this scenario.

Correct Answer: C

Rationale: When a nurse observes periods of apnea in a client experiencing Cheyne-Stokes respirations, measuring the length of the apneic periods is essential. This action helps in determining the severity of Cheyne-Stokes respirations by providing valuable information about the duration of interrupted breathing cycles. Elevating the head of the client's bed (Choice A) may be beneficial in some respiratory conditions but is not the priority in Cheyne-Stokes respirations. Auscultating the client's breath sounds (Choice B) is a general assessment and may not directly address the issue of apnea in Cheyne-Stokes respirations. Suctioning the client's oropharynx (Choice D) is not the initial intervention for managing Cheyne-Stokes respirations unless secretions are obstructing the airway.

Correct Answer: C

Rationale: The correct answer is C. Partial thromboplastin time (PTT) is the laboratory value that should be monitored to evaluate the effectiveness of heparin therapy. PTT reflects the intrinsic pathway of coagulation and is specifically sensitive to heparin's anticoagulant effects. Monitoring the PTT helps ensure that the client is within the therapeutic range to prevent clot formation without increasing the risk of bleeding. Choices A, B, and D are incorrect because while they are important laboratory values in other contexts, they are not specifically used to monitor the effectiveness of heparin therapy.