Hypotension in Preterm Infants with Significant Patent Ductus Arteriosus: Effects of Dopamine

Objective

To study the effects of dopamine on systemic arterial pressure (SAP) and systemic blood flow (SBF) (estimated with the superior vena cava [SVC] flow) in preterm infants with hypotension and patent ductus arteriosus (PDA).

Study design

Clinical and echocardiographic variables were measured before and 2 hours after starting dopamine in premature infants <32 weeks gestational age with PDA and systemic hypotension.

Results

Seventeen premature infants were included (gestational age, 28±2 weeks; birth weight, 1030 ± 400 g). A mean rate of 8 ± 2μg/kg/min of dopamine raised SAP from 30 ± 3 to 41 ± 5 mm Hg (P < .05), and the pulmonary artery pressures from 25 ± 5 to 32 ± 8 mm Hg (P < .05). The SVC flow increased by 30% (from 130 ± 40 to 170 ± 44 mL/kg/min; P < .05). The left ventricular output and the end-diastolic and mean left pulmonary artery blood flow velocities did not change despite the increase in pulmonary artery pressure.

Conclusion

In preterm infants with hypotension and PDA, dopamine (<10 μg/kg/min) increases the systemic blood pressure and the systemic blood flow. Our results suggest that dopamine decreases left-to-right shunting across ductus arteriosus, caused by a rise in pulmonary vascular resistances.

Abbreviations: DA, Ductus arteriosus, LA: Ao, Left atrial /aortic root ratio, PAP, Pulmonary artery pressures, PDA, Patent ductus arteriosus, PVR, Pulmonary vascular resistance, SAP, Systemic arterial pressure, SBF, Systemic blood flow, SpO₂, Oxygen saturation, SVC, Superior vena cava, SVR, Systemic vascular resistances