Low-dose vasopressin infusion therapy for refractory hypotension in ELBW infants.

Background: Severe hypotension in infants, especially in preterm infants, is associated with poor neurological outcome and high mortality. In adults, low-dose vasopressin (arginine vasopressin: AVP) infusion therapy has been effective for treating hypotension that is refractory to vasopressors and inotropes.

Methods: The effects of AVP infusion therapy for refractory hypotension were retrospectively evaluated in extremely low-birthweight infants. Between January 2002 and November 2005, 22 infants with refractory hypotension treated with low-dose AVP infusion were reviewed. The average birthweight was 658 g (+/-142 g), and the average gestational age was 24.9 weeks (+/-1.4). The changes in blood pressure, urinary output, and other parameters in response to AVP therapy were analyzed in all the infants.

Results: After AVP infusion, systolic blood pressure increased from 30 mmHg to 43 mmHg (P < 0.0001), and the diastolic pressure increased from 15 mmHg to 24 mmHg (P < 0.0001). The urine output dramatically increased from 1.5 mL/kg per h to 4.0 mL/kg per h (P < 0.0001). AVP infusion, however, was not effective in four of the 22 patients (18%). The sodium concentration in the serum decreased mildly after administration. In six patients the serum sodium concentration decreased below 130 mEq/L. Severe mitral regurgitation was observed in two patients. Three infants showed a transient decrease in the platelet count during AVP infusion.

Conclusions: Low-dose AVP therapy should be considered as rescue therapy when high-dose catecholamine therapy and/or steroid administration do not produce sufficient increase in the blood pressure. Further investigations are required to prove the efficacy and safety of AVP infusion therapy in preterm infants.