Correct Answer: B

Rationale: The correct answer is B: Respiratory alkalosis. Hyperventilation, which can be caused by extreme anxiety, is the most common cause of acute respiratory alkalosis. This leads to a decrease in PaCO2 levels. Respiratory acidosis, choice A, occurs in conditions like hypoventilation, leading to an increase in PaCO2 levels. Choice C, Increased PaCO2, is not the correct term for an acid-base imbalance related to hyperventilation. Choice D, CNS disturbances, is not directly related to the acid-base imbalance caused by hyperventilation.

Correct Answer: D

Rationale: Intracellular fluid contains phosphate ions and protein molecules as essential anions. Phosphate ions play a crucial role in various cellular processes, including energy transfer. Proteins, being large molecules with negative charges, also contribute significantly to the negative ion concentration within cells. Chlorine is primarily an extracellular anion and is not as prominent as phosphate ions and proteins within intracellular fluid, making it a less important negative ion in this context. Therefore, the correct answer is D because both phosphate ions and protein molecules are crucial negative ions in intracellular fluid.

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: A

Rationale: Corrected Rationale: To assess a patient's magnesium status, the nurse should check deep tendon reflexes. Diminished deep tendon reflexes may indicate high serum magnesium levels, as hypermagnesemia can lead to neuromuscular effects. Tachycardia, cool clammy skin, and acute flank pain are not typically associated with high magnesium levels and are not priority assessments in this situation.

Correct Answer: B

Rationale: Chloride (Cl-) is the most abundant anion in blood plasma. It plays a crucial role in maintaining osmotic balance and acid-base homeostasis. Bicarbonate (Choice A) is important for buffering acids in the body but is not the most abundant negative ion in blood plasma. Hydroxide (Choice C) is not typically found in high concentrations in blood plasma. Phosphate (Choice D) is an important anion in the body but is not as abundant as chloride in blood plasma.