Pilot safety study of low-dose vasopressin in non-septic critically ill children

To assess the safety of low-dose vasopressin infusion in critically ill children requiring prolonged mechanical ventilation (MV) at risk of developing sedation/analgesia-related hypotension. Randomized pilot safety study in children expected to require MV for at least 3 days. Children received either vasopressin (0.0005 U/kg/min) or sodium chloride (0.9%) infusion for a period of 48 h. Haemodynamic variables, urine output and serum electrolytes were closely monitored and analyzed. Twelve children in each group had similar baseline characteristics. Vasopressin infusion was associated with an 8 mmol/L fall in serum sodium concentration (p < 0.01) and with higher incidence of hyponatraemia (8 vs. 66%, p < 0.01). In normotensive children, low-dose vasopressin also induced a reversible decrease in urine output, and acutely increased blood pressure (p < 0.01). After stopping the vasopressin there was rebound hypotension (p < 0.01). Low-dose vasopressin infusion in haemodynamically stable, but critically ill, children is associated with reduction in urine output and decreased serum sodium level, yielding a high incidence of hyponatraemia. We conclude that these effects limit further study of prophylactic vasopressin for sedation-related hypotension in a randomized controlled trial.