Correct Answer: B

Rationale: The symptoms described, including tingling in the lips and fingers, intermittent spasms, and increased muscle tone, are indicative of tetany, which is a common manifestation of hypocalcemia. Hypocalcemia can lead to neuromuscular irritability, causing symptoms such as paresthesias and muscle spasms. Hypophosphatemia primarily affects the central nervous system, resulting in seizures and coma. Hypermagnesemia typically presents with hypoactive reflexes and somnolence. Hyperkalemia can cause paresthesias and anxiety, but in this case, the patient's symptoms are more suggestive of hypocalcemia.

Correct Answer: A

Rationale: The correct answer is A: 80%. Newborns can have a body water content as high as 80% due to their higher total body water compared to adults. Choice B (70%) is incorrect because newborns typically have a higher body water percentage. Choice C (60%) is also incorrect as it underestimates the body water content in newborns. Choice D (90%) is incorrect as it overestimates the body water percentage in newborns.

Correct Answer: D

Rationale: When a patient exhibits signs and symptoms of third-spacing, where fluid moves out of the intravascular space but not into the intracellular space, hypovolemia is expected. This leads to a decreased circulating blood volume. Increased calcium and magnesium levels are not typically associated with third-spacing fluid shift. Burns usually result in acidosis rather than alkalosis, making metabolic alkalosis an incorrect choice. Therefore, hypovolemia is the correct answer in this scenario.

Correct Answer: D

Rationale: The correct answer is D. All the listed organs (lungs, skin, and intestines) contribute to fluid loss from the body. Lungs contribute to fluid loss through respiration, skin through sweating, and intestines through excretion. Therefore, none of the organs listed in the options retain fluids within the body. Choices A, B, and C are incorrect because all of these organs play a role in fluid output from the body.

Correct Answer: D

Rationale: A low pH indicates acidosis (normal pH is 7.35 to 7.45). The PaCO2 is also low, which causes alkalosis. The bicarbonate is low, which causes acidosis. The pH bicarbonate more closely corresponds with a decrease in pH, making the metabolic component the primary problem. Therefore, the correct interpretation of the arterial blood gas results is metabolic acidosis with a compensatory respiratory alkalosis. Choices A, B, and C are incorrect because they do not accurately reflect the primary acid-base disturbance and the compensatory response seen in the given results.