Parathyroid hormone as a marker for hypoperfusion in trauma: A prospective observational study.

BACKGROUND Hyperparathyroidism is common in critical illness. Intact parathyroid hormone has a half-life of 3 minutes to 5 minutes due to rapid clearance by the liver, kidneys, and bone. In hemorrhagic shock, decreased clearance may occur, thus making parathyroid hormone a potential early marker for hypoperfusion. We hypothesized that early hyperparathyroidism predicts mortality and transfusion in trauma patients. METHODS A prospective observational study was performed at a Level I trauma center in consecutive adult patients receiving the highest level of trauma team activation. Parathyroid hormone and lactic acid were added to the standard laboratory panel drawn in the trauma bay on arrival, before the administration of any blood products. The primary outcomes assessed were transfusion in 24 hours and mortality. RESULTS Forty-six patients were included. Median age was 47 years, 82.6% were men, 15.2% suffered penetrating trauma, and 21.7% died. Patients who were transfused in the first 24 hours (n = 17) had higher parathyroid hormone (182.0 pg/mL vs. 73.5 pg/mL, p < 0.001) and lactic acid (4.6 pg/mL vs. 2.3 pg/mL, p = 0.001). Patients who did not survive to discharge (n = 10) also had higher parathyroid hormone (180.3 pg/mL vs. 79.3 pg/mL, p < 0.001) and lactic acid (5.5 mmol/L vs. 2.5 mmol/L, p = 0.001). For predicting transfusion in the first 24 hours, parathyroid hormone has an area under the receiver operating characteristic curve of 0.876 compared with 0.793 for lactic acid and 0.734 for systolic blood pressure. Parathyroid hormone has an area under the receiver operating characteristic curve of 0.875 for predicting mortality compared with 0.835 for lactic acid and 0.732 for systolic blood pressure. CONCLUSION Hyperparathyroidism on hospital arrival in trauma patients predicts mortality and transfusion in the first 24 hours. Further research should investigate the value of parathyroid hormone as an endpoint for resuscitation. LEVEL OF EVIDENCE Prognostic, level II.