Correct Answer: B

Rationale: The correct answer is B: Blood glucose: 524 mg/dL. The patient likely has diabetic ketoacidosis (DKA) due to missed insulin doses, stress, and illness leading to high blood glucose levels. DKA is characterized by hyperglycemia, ketosis, and metabolic acidosis. A low blood glucose level (Choice A) is not consistent with DKA. HCO3- of 10 mEq/L (Choice C) indicates metabolic acidosis, but it's not specific to DKA. A PaCO2 of 37 mm Hg (Choice D) is within the normal range and not directly related to DKA.

Correct Answer: A

Rationale: The correct answer is A because renin activates the renin-angiotensin-aldosterone cascade. Renin is released by the kidneys in response to low blood pressure or low sodium levels. It acts on angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme. Angiotensin II causes vasoconstriction, leading to increased blood pressure, and stimulates aldosterone release, promoting sodium and water retention. Choice B is incorrect because renin does not suppress angiotensin production; it actually initiates the process. Choice C is incorrect because renin's action leads to increased sodium reabsorption by stimulating aldosterone release. Choice D is incorrect because renin does not inhibit aldosterone release; it promotes it as part of the renin-angiotensin-aldosterone cascade.

Correct Answer: C

Rationale: Step 1: Syndrome of inappropriate antidiuretic hormone (SIADH) leads to excess water retention, diluting sodium levels in the blood. Step 2: Fluid restriction is the mainstay of treatment to prevent further dilution of sodium. Step 3: Administering 3% normal saline (choice A) can worsen the condition by further increasing sodium levels. Step 4: Exogenous vasopressin (choice B) would exacerbate the problem by increasing water retention. Step 5: Low sodium diet (choice D) may be beneficial in the long term but is not the immediate priority.

Correct Answer: B

Rationale: The correct answer is B: prepare for intubation and mechanical ventilation. The patient's arterial blood gas results indicate metabolic acidosis (low pH, low bicarbonate) with respiratory compensation (low PCO). In this scenario, the patient is likely experiencing respiratory fatigue due to tachypnea from metabolic acidosis. Intubation and mechanical ventilation are needed to support the patient's respiratory effort and correct the acid-base imbalance. Administering morphine (choice A) can further depress the respiratory drive. Administering intravenous sodium bicarbonate (choice C) can temporarily correct the pH but does not address the underlying respiratory distress. Canceling dialysis (choice D) is not indicated as it does not address the acute respiratory compromise.

Correct Answer: B

Rationale: The correct answer is B: Hypovolemic shock. After pituitary surgery, patients are at risk for hypovolemic shock due to potential intraoperative blood loss and fluid shifts. Monitoring for signs of shock, such as hypotension and tachycardia, is crucial for early intervention. A: Congestive heart failure is less likely immediately post-surgery. C: Infection is a concern but not the highest priority in the immediate postoperative period. D: Volume overload is not a common immediate complication of pituitary surgery.