Summary proceedings from the cardiology group on cardiovascular instability in preterm infants

The appropriate determination of adequate tissue perfusion and the best approach to treatment of perceived abnormalities in blood pressure in the neonate remain controversial. There is no consensus regarding the actual definition of hypotension in the neonate or how best to raise perceived low blood pressure. In addition, there is no direct and prospectively collected information available on the result of treatment of a "low" blood pressure on neonatal morbidity and mortality. It also has not been clearly demonstrated that bringing systemic blood pressure to a "normal" range improve outcomes. However, it is widely accepted by clinicians that early and aggressive treatment of hypotension leads to improved neurologic outcome and survival in the neonate. Commonly used therapeutic maneuvers to correct systemic hypotension in the neonate include volume expansion, inotropic agents, and corticosteroids. Although there is a paucity of research on the cardiovascular response to these commonly used agents in neonates, among the commonly used inotropic drugs dopamine has been shown to be more effective than dobutamine in raising blood pressure in the neonate. The cardiology group focused on the use of inotropes, particularly dopamine and dobutamine, to treat very low birth weight infants with cardiac instability and neonatal postoperative cardiac patients. The cardiology group identified key issues that must be considered when designing studies of inotropic agents in preterm infants and proposed 2 clinical-trial designs: (1) a placebo-controlled trial with rescue for symptomatic infants; and (2) a targeted-blood pressure study. The first trial design would answer questions concerning efficacy of treatment with inotropic agents in this population. The second trial design would address concerns related to the lack of knowledge on normal blood pressure ranges in this population. The group identified specific design elements that would need to be addressed for the complicated trial design to study inotropic agents in neonates.