Electrolyte Monitoring in AKI

A nurse is managing a patient with acute kidney injury (AKI) who is on a strict fluid restriction. The patient has been experiencing nausea, vomiting, and lethargy. Recent lab results reveal hyperphosphatemia and hypocalcemia. When planning care for this patient, which of the following electrolyte imbalances is the nurse most likely to monitor for in addition to the already identified issues?