Correct Answer: A

Rationale: The correct answer is A: Assess the airway. The nurse should prioritize airway assessment as the client's ABGs indicate respiratory acidosis (low pH, high PaCO2). This suggests potential airway obstruction or inadequate ventilation. Ensuring a patent airway is crucial for adequate oxygenation. Administering bronchodilators (B) or mucolytics (D) may help with airway clearance but should come after ensuring a clear airway. Providing oxygen (C) is important, but addressing the underlying respiratory acidosis by first assessing the airway is the priority in this situation to prevent further deterioration.

Correct Answer: A

Rationale: The correct answer is A: Substantially reduced renal function. In older adults, elevated serum creatinine levels can indicate impaired kidney function, as the kidneys may not filter waste products as efficiently. This can lead to a buildup of creatinine in the blood. Acute kidney injury (Choice B) is a sudden decline in kidney function and would typically present with a more significant increase in creatinine levels. Decreased cardiac output (Choice C) would not directly cause elevated creatinine levels. Alterations in the ratio of body fluids to muscle mass (Choice D) would not be a common cause of elevated creatinine levels in this scenario.

Correct Answer: C

Rationale: The correct answer is C. The client's high serum potassium level of 7.5 mEq/L can lead to serious cardiovascular complications like arrhythmias. The immediate priority is to lower potassium levels rapidly to prevent cardiac arrest. Administering dextrose 20% and regular insulin IV push helps shift potassium from extracellular to intracellular space, lowering serum levels quickly. Option A (Kayexalate) is not as rapid as insulin therapy. Option B (low-potassium diet) is not immediate. Option D (hemodialysis) is effective but not as quick as insulin therapy for urgent potassium reduction.

Correct Answer: D

Rationale: The correct answer is D: Teach the client fall prevention measures. In metabolic alkalosis, the client may experience muscle weakness and confusion, increasing the risk of falls. Teaching fall prevention measures is essential to ensure the client's safety. Monitoring hemoglobin and hematocrit values (A) is not directly related to managing metabolic alkalosis. Administering furosemide (B) is not appropriate for metabolic alkalosis. Encouraging deep breaths (C) may not address the underlying cause of the alkalosis.

Correct Answer: B

Rationale: The correct answer is B: Osmosis and osmolality. When a hypertonic solution is infused, it increases the number of dissolved particles in the blood, creating an osmotic pressure gradient. This causes fluids in the tissues to shift into the capillaries, increasing blood volume. Osmosis is the movement of solvent (water) across a semi-permeable membrane to equalize solute concentrations. Osmolality refers to the concentration of solutes in a solution. Hydrostatic pressure (choice A) is the force exerted by a fluid against a wall when it is under pressure, not related to the movement of solutes. Diffusion (choice C) is the movement of solute molecules from an area of high concentration to low concentration, not involving a semi-permeable membrane. Active transport (choice D) requires energy to move molecules across a membrane against their concentration gradient, not the mechanism described in the scenario.