Slow, shallow breathing allows carbonic acid to build up in the blood, returning pH to normal.

Correct Answer: A

Rationale: Slow, shallow breathing leads to the retention of carbon dioxide in the blood, which combines with water to form carbonic acid. This accumulation of carbonic acid triggers the body's buffering system, helping to return the blood pH to normal levels. Therefore, slow, shallow breathing allowing carbonic acid buildup to regulate blood pH is true. The other choices (B, C, D) are incorrect as they do not provide a logical explanation for the relationship between breathing rate, carbonic acid levels, and blood pH regulation.

Correct Answer: A

Rationale: The correct interpretation of the arterial blood gas results is Respiratory Alkalosis. 1. pH > 7.45 indicates alkalosis. 2. PaCO2 < 35 mm Hg indicates respiratory alkalosis. 3. HCO3 within normal range (22-26 mEq/L) rules out metabolic imbalance. Therefore, the primary abnormality is a low PaCO2 causing alkalosis. Other choices are incorrect because there is no evidence of metabolic alkalosis (HCO3 normal), respiratory acidosis (PaCO2 high), or base balance (not a specific acid-base imbalance).

Correct Answer: D

Rationale: The correct answer is D: Monitor for Trousseau's and Chvostek's signs. A calcium level of 12.1 mg/dL indicates hypercalcemia, which can lead to neuromuscular irritability. Trousseau's and Chvostek's signs are manifestations of hypocalcemia, but in the context of hypercalcemia, they may also present due to the calcium imbalance affecting neuromuscular function. Therefore, monitoring for these signs is crucial for early detection of potential complications. Choice A is incorrect because bed rest is not specifically indicated for hypercalcemia unless there are other medical reasons necessitating it. Choice B is incorrect because auscultating lung sounds every 4 hours is not directly related to managing hypercalcemia. Choice C is incorrect because encouraging fluid intake up to 4000 mL daily may not be appropriate without considering the patient's renal function and the potential risk of fluid overload in the context of hypercalcemia.

Correct Answer: D

Rationale: The correct answer is D. Teaching the patient to take slow, deep breaths when anxious is the first action the nurse should take. The patient is experiencing respiratory alkalosis, likely due to hyperventilation from anxiety. Teaching the patient relaxation techniques can help normalize the respiratory rate and improve oxygenation. Checking the nasogastric tube (A) can be done later as it is not the priority. Giving morphine (B) may further depress respiratory drive and worsen the alkalosis. Notifying the health care provider (C) is not necessary at this moment as the nurse can address the situation effectively.

Correct Answer: D

Rationale: The correct answer is D because the presence of coarse, muddy brown granular casts in the urinalysis indicates intrarenal disease, specifically acute tubular necrosis. This condition is characterized by damage to the renal tubules, leading to the presence of casts in the urine. The patient's symptoms of malaise, fatigue, and decreased urinary output are consistent with acute tubular necrosis. Choice A is incorrect because it does not specify the underlying cause of the kidney injury. Choice B is incorrect as prerenal conditions would typically present with different urinalysis findings. Choice C is incorrect as postrenal obstruction would not typically lead to the presence of granular casts in the urine.