Changes in hemodynamics after rescue surfactant administration

OBJECTIVE: To evaluate the hemodynamic changes occurring after rescue surfactant dosing in relation to the clinical respiratory response in preterm infants with respiratory distress syndrome. STUDY DESIGN: We studied 20 infants who received surfactant (poractant alfa) after failing continuous positive airway pressure (CPAP) beyond 2 h of life. Consecutive echocardiograms were performed before the surfactant dose, 10 min after and 1 h after the surfactant dose. Superior vena cava flow, right ventricular output, atrial and patent ductus arteriosus diameter and direction of shunting were measured. A surfactant responder (SR) was defined as an infant whose inspired fraction of oxygen was reduced to air (0.21) by 3 h after surfactant administration. A surfactant non-responder (SNR) was defined as an infant who remained on more than 0.21 at 3 h postsurfactant administration. Concurrent physiological parameters (heart rate, transcutaneous CO2, mean arterial blood pressure, mean airway pressure) were also recorded. Subject characteristics were compared relative to noted hemodynamic effects. RESULT: Of the 20 infants enrolled in the study, 12 were SR. These infants received surfactant earlier and had increased measures of systemic blood flow after receipt of surfactant compared with baseline. SNR did not have changes in systemic blood flow from baseline after surfactant dosing. There was no change in ductal shunting or atrial shunting between the two groups. CONCLUSION: A good clinical response to rescue surfactant is seen in infants who received surfactant earlier and is associated with increase in systemic blood flow. Timing of rescue surfactant administration needs to be further evaluated in larger prospective studies.