[Trends in parathyroid hormone plasma concentration in critically ill patients: prospective observational study].

Introduction: There is no data in the literature regarding trends in parathormone serum concentration assessment in critically ill patients. The aim: To assess the parathyroid hormone plasma concentrations and kinetics in critically ill patients admitted to the intensive care unit due to multiorgan failure. Materials and methods: Thirty multiorgan failure (at least circulatory and respiratory failure) patients were included. Patients who met any of the following criteria were excluded: acute liver failure, end stage renal disease, hypercalcemia, parathyroid gland disease, severe vitamin D deficiency, admission from another ICU or readmission, age younger than 18 years, or lack of consent from relatives. We performed the parathyroid hormone plasma measurements in 12-hour time intervals. Results: The initial parathyroid hormone plasma concentration levels in the study group were rather variable and medians exceeded laboratory reference values. Especially in the acute kidney injury subpopulation treated with continuous renal replacement therapy these trends were emphasized. The initial parathyroid hormone plasma concentration levels in this group significantly exceeded laboratory reference values in 80% of patients. After initial spike we observed subsequent drop between second and third measurement. The distribution of plasma levels was rather variable between second and third measurement in this group of patients. Conclusions: The parathyroid hormone plasma concentration levels in the critically ill patients are variable. In the acute kidney injury subpopulation treated with continuous renal replacement therapy after initial significant spike we observed subsequent drop between second and third measurement.