The kidneys respond to acid-base disturbances by:

Choice A reason: Intracellular to the extracellular fluid shift is not the cause of low blood pressure in this case. This fluid shift occurs when the cells lose water due to osmosis, such as in dehydration or hypernatremia.

Choice B reason: Interstitial to intravascular fluid shift is not the cause of low blood pressure in this case. This fluid shift occurs when the fluid moves from the tissue spaces to the blood vessels, such as in hypovolemia or hypotonic fluid administration.

Choice C reason: Interstitial to the intracellular fluid shift is not the cause of low blood pressure in this case. This fluid shift occurs when the fluid moves from the tissue spaces to the cells, such as in overhydration or hyponatremia.

Choice D reason: Intravascular to the interstitial fluid shift is the cause of low blood pressure in this case. This fluid shift occurs when the fluid moves from the blood vessels to the tissue spaces, such as in edema, inflammation, or increased capillary permeability. This reduces the blood volume and lowers the blood pressure.

Choice A reason: This is incorrect because sodium level of 145 mEq/L is within the normal range of 135 to 145 mEq/L. Sodium is not directly affected by respiratory alkalosis, but it may be altered by fluid balance or other conditions.

Choice B reason: This is incorrect because magnesium level of 1.3 mEq/L is within the normal range of 1.3 to 2.1 mEq/L. Magnesium is not directly affected by respiratory alkalosis, but it may be altered by renal function or other conditions.

Choice C reason: This is incorrect because phosphorus level of 3.0 mg/dL is within the normal range of 2.5 to 4.5 mg/dL. Phosphorus is not directly affected by respiratory alkalosis, but it may be altered by calcium balance or other conditions.

Choice D reason: This is correct because potassium level of 3.0 mEq/L is below the normal range of 3.5 to 5.0 mEq/L. Potassium is inversely related to hydrogen ions, which are decreased in respiratory alkalosis. As hydrogen ions move out of the cells to buffer the blood, potassium ions move into the cells to maintain electrical neutrality. This causes hypokalemia, or low potassium level.