Background Cardiovascular dysfunction, a consequence of perinatal asphyxia, contributes significantly to its morbidity and mortality. The use of vasopressin, an endogenous hormone commonly given to adults with refractory shock, in neonates is limited by concerns over mesenteric perfusion. We recently showed that vasopressin had dose-dependent baro-specific effects with possible cardioprotection at low doses (0.005–0.01 units/kg/h) in a swine model of neonatal hypoxia-reoxygenation (H-R). We aimed to compare systemic and regional hemodynamic effects of low-dose vasopressin and dobutamine, a synthetic beta-adrenoceptor agonist.
Methods Piglets (1–5 day-old, 1.6–2.2kg) were anesthetized and instrumented to continuously monitor systemic hemodynamic parameters including cardiac output (CO), and carotid and mesenteric flow indices. After 2h of hypoxia (10–15% O2), piglets had normoxic reoxygenation for 4h. In a blinded randomized fashion, piglets received either vasopressin (0.01 units/kg/h started at 30min of reoxygenation) or dobutamine (20 mcg/kg/min started at 2h of reoxygenation)(n=8/group). H-R controls (placebo) and sham-operated piglets were also performed. Plasma troponin-I levels, tissue lactate levels and histology of left ventricle and small bowel were analyzed.
Results H-R piglets had cardiogenic shock and metabolic acidosis, which recovered upon reoxygenation. During recovery CO, carotid and mesenteric flows gradually deteriorated and were increased similarly in vasopressin- and dobutamine-treated piglets (p<0.05 vs. controls). Troponin, ventricular and intestinal lactate levels were reduced in vasopressin-treated piglets (p<0.05 vs. controls), with no difference in histological analysis among groups.
Conclusion Low-dose vasopressin improves systemic and regional hemodynamics similarly to dobutamine and confers a cardioprotective effect in a swine model of neonatal H-R.