Correct Answer: A

Rationale: A serum potassium level of 2.5 mEq/L is critically low, indicating severe hypokalemia. The immediate action the nurse should take is to inform the healthcare provider of the need for potassium replacement. Option B, preparing to administer glucose-insulin-potassium replacement, is not the first-line intervention; it may be considered in specific situations but requires a healthcare provider's prescription. Option C, changing the plan of care to include hourly urinary output measurement, is not the priority when managing critically low potassium levels. Option D, instructing the client to increase daily intake of potassium-rich foods, is not appropriate in this acute situation where immediate intervention is needed to address the dangerously low potassium level.

Correct Answer: A

Rationale: Smoking is the correct answer as it is a well-established common cause of chronic obstructive pulmonary disease (COPD). Smoking leads to long-term damage to the lungs, contributing to the development of COPD. Choice B, asthma, is not a cause but a separate respiratory condition characterized by airway inflammation and hyperresponsiveness. Allergies, choice C, are not a direct cause of COPD but can exacerbate symptoms in individuals with existing COPD. Chronic bronchitis, choice D, is a type of COPD, not a cause of COPD itself, making it an incorrect choice in this context.

Correct Answer: C

Rationale: The correct answer is C: Hyperkalemia. Sodium polystyrene sulfonate (Kayexalate) is used to treat high potassium levels (hyperkalemia) by exchanging sodium ions for potassium ions in the large intestine, which is then eliminated through the feces. Therefore, the nurse should monitor the client for changes in potassium levels to ensure the effectiveness of the treatment. Choices A, B, and D are incorrect because sodium polystyrene sulfonate (Kayexalate) is not associated with causing hyponatremia, hypokalemia, or hypocalcemia.

Correct Answer: D

Rationale: The correct instruction for a client with chronic heart failure is to report any weight gain of more than 2 to 3 pounds in a day. This weight gain may indicate fluid retention, which is a critical sign of worsening heart failure. Weighing at the same time every day and using the same scale for consistency are good practices, but the crucial action is to promptly report significant weight gain, as stated in option D. Recording the weight in a journal or log can be helpful for tracking trends, but immediate reporting of weight gain is essential for timely intervention in heart failure management. Therefore, option D is the most appropriate instruction for this client.

Correct Answer: B

Rationale: Administering oxygen is a priority intervention in heart failure because it helps improve oxygenation, alleviate hypoxemia, and reduce the workload on the heart. Oxygen therapy is crucial in managing acute heart failure exacerbations. While diuretics (Choice A) are commonly used in heart failure to reduce fluid overload, administering oxygen takes precedence due to its immediate impact on oxygen delivery. Beta-blockers (Choice C) and vasodilators (Choice D) are also important in heart failure management, but in the acute setting, ensuring adequate oxygen supply is the priority.