Which acid-base disturbances are associated with hypophosphatemia according to the risk factors?

Which acid-base disturbances are associated with hypophosphatemia according to the risk factors?

• A. Respiratory alkalosis
• B. Metabolic acidosis
• C. Respiratory and metabolic alkalosis
• D. No acid-base disturbance

Answer: (C)

Phosphate moves between the extracellular space and inside cells in response to the body’s acid-base state. In alkalemia, the higher pH promotes phosphate to shift into cells to help buffer the increased pH, which lowers the amount circulating in the blood. This intracellular shift occurs with both respiratory alkalosis (low CO2 causing higher pH) and metabolic alkalosis (high HCO3− causing higher pH). So, serum phosphate can drop even if total body phosphate isn’t depleted, making hypophosphatemia a risk in both respiratory and metabolic alkalosis.

Phosphate moves between the extracellular space and inside cells in response to the body’s acid-base state. In alkalemia, the higher pH promotes phosphate to shift into cells to help buffer the increased pH, which lowers the amount circulating in the blood. This intracellular shift occurs with both respiratory alkalosis (low CO2 causing higher pH) and metabolic alkalosis (high HCO3− causing higher pH). So, serum phosphate can drop even if total body phosphate isn’t depleted, making hypophosphatemia a risk in both respiratory and metabolic alkalosis.