P0776 - Utility of Vasopressin Rescue Therapy in Neonates with Persistent Pulmonary Hypertension of the Newborn

Background: Persistent pulmonary hypertension of newborn (PPHN) affects 1.9 per 1000 live births and has a varied mortality ranging between 4-33%. Although inhaled nitric oxide (iNO) has reduced the need for Extracorporeal membrane oxygenation (ECMO) in this population, refractory cases persist. Vasopressin is gaining favor as a treatment modality in neonates despite limited data and concerns for hyponatremia and decreased intestinal perfusion.

Objective: To describe the effect of vasopressin on oxygenation and systemic blood pressure in neonates with PPHN compared to matched controls.

Method: Retrospective chart review of neonates admitted with PPHN at a single tertiary NICU between 01/01/2017 and 12/31/2019. Neonates receiving vasopressin were matched to controls by birth weight, gestational age, sex and initial oxygenation index (OI).

Results: A total of 14 neonates with PPHN were identified, 7 who received vasopressin and 7 corresponding controls. There was no difference in neonatal characteristics between groups (Table 1). In the vasopressin group, mean initial vasopressin dose was 40 mU/kg/hr, mean initiation time 30 hours of life, and mean duration 70 hours. Significant OI reduction was seen at 12 hours (p=0.003) and 24 hours (p=0.001) after initiation of vasopressin (Table 2). There was significant improvement in mean arterial pressure (MAP) within 1 hour (p=0.004) along with decrease in inotropic score by 6 hours (p= 0.0012) and vasoactive-inotropic score by 24 hours (p=0.019). There was no significant change in serum lactate or urine output, however, a decrease in serum sodium was noted by 12 hours (p=0.019).

Compared to the control group, the vasopressin group showed a trend towards improved OI within 12 hours (p=0.07, Fig 1) and statistically significant improvement in MAP within 1 hour of starting vasopressin (p= 0.044, Fig 2). Double the patients in the control group required ECMO for the management of refractory PPHN though not statistically significant. There was no difference in survival and no cases of necrotizing enterocolitis in either group.

Conclusion: This study suggests that vasopressin can be safely used as an adjunct therapy to improve oxygenation and augment blood pressure in cases with refractory PPHN. Close monitoring and management of hyponatremia is warranted. Next steps include a prospective cohort study to assess if vasopressin rescue therapy reduces the need for ECMO in this population.