measured serially over the first 24 postnatal hours Mean ductal size was larger, heart rate higher, and blood pressure lower in the milrinone group No difference was identified in the primary outcome of low superior vena cava flow or in the secondary outcome of intraventricular hemorrhage Hypotension was present in 43% (milrinone: n = 21, 50%; placebo: n = 38, 38%) of patients prior to study drug Potential contributors to deranged hemodynamics (e.g., oxygenation, etiology of pretreatment hypotension, airway pressure) were not provided Osborn D, Evans N, Kluckow M Randomized trial of dobutamine versus dopamine in preterm infants with low systemic blood flow J Pediatr 2002;140(2):183–191 Preterm infants born less than 30 weeks’ gestation and less than 24-hour postnatal age with low superior vena cava flow (SVC) were recruited to a blinded crossover trial to identify the impact of dopamine vs dobutamine on systemic blood flow Neonates were randomly assigned to either dopamine (n = 20) or dobutamine (n = 22) as first line therapy after volume If sufficient increase in SVC flow was not identified on 20 µg/kg/min of the first drug, the neonate crossed over to the other medication Dobutamine produced a median 35% increase (range 15%, +31%) in SVC flow while dopamine produced a median 1% decrease (range −70%, 94%) Dopamine produced a greater increase in mean BP (P = 0.003) These data suggest that dobutamine may be a better initial therapy for disorders of myocardial performance, whereas first-line dopamine may be indicated for disorders of low systemic vascular resistance McNamara PJ, Stewart L, Shivananda SP, Stephens D, Sehgal A Patent ductus arteriosus ligation is associated with impaired left ventricular systolic performance in premature infants weighing less than 1000g J Thorac Cardiovasc Surg 2010;140:150–157 Preterm infants (n = 46) with a hemodynamically significant ductus arteriosus undergoing ligation were assessed serially before and after surgery to characterize the changes in left ventricular (LV) performance in response to altered loading conditions Ligation was followed by an increase in exposed vascular resistance that temporally coincided with reduced LV preload, output, and contractility Neonates less than 1000 g had a greater likelihood of impaired function, low LV output, and greater need for inotropes The median time for initiation of cardiotropic support was 10 hours (IQR 6-12), corresponding to the period of lowest cardiac output This corresponds to other neonatal and primate data that cumulative exposure to increased vascular resistance, and not the immediate reduction in preload, was the primary driver of postoperative instability in this study Su PH, Chen JY Inhaled nitric oxide in the management of preterm infants with severe respiratory failure J Perinatol 2008;28:112– 116 Neonates less than 31 weeks with oxygenation index (OI) greater than 25 were randomized to receive 5 ppm of inhaled nitric oxide (iNO, n = 32) or placebo (n = 33) Head ultrasound (every 12 hours) was standardized, but echocardiography (clinician's discretion) was not iNO-treated infants had a reduction in OI by 43% versus 11% in placebo-treated infants (P = 0.01) after 30 minutes of treatment It took 3 hours for iNO-treated infants to attain OI less than 15 versus 48 hours in the placebo group There was no significant difference in neonatal mortality or morbidities, including intracranial hemorrhage, bronchopulmonary dysplasia, or