Vasopressin and copeptin levels in children with sepsis and septic shock

Levels of vasopressin and its precursor copeptin in pediatric sepsis and septic shock are not well defined. The main aim of this study is to compare the serum levels of vasopressin and copeptin in children with septic shock or sepsis and in healthy children. We hypothesized that vasopressin and copeptin levels are elevated in early and late stages of pediatric septic shock. Three groups were included: healthy children, children with clinical diagnosis of sepsis, and children admitted to the pediatric intensive care unit (PICU) with diagnosis of sepsis shock. Blood samples were drawn from children in all groups within 24 h of admission. For the septic shock group, additional samples at 24-h intervals were drawn up to 120 h after PICU admission. We used competitive immunoassays to determine vasopressin and copeptin levels. There were 70 children in the control group, 53 children in the sepsis group, and 13 in the septic shock group. At baseline, there was a difference in median vasopressin levels [60.9 (Interquartile range: 32.3, 138.0) vs. 141.1 (45.2, 542) vs. 326 (55.6, 399) pg/mL, p < 0.05], but there was no difference in copeptin levels [1.2 (0.8, 1.8) vs. 1.5 (1.0, 2.2) vs. 0.9 (0.8, 1.2) ng/mL, p = 0.14] between the three groups. There was no difference in vasopressin and copeptin levels in early and late stages of pediatric septic shock. Baseline vasopressin levels were different between the three groups. In pediatric septic shock, vasopressin and copeptin levels are not robust markers for severity and clinical outcomes.