Patent ductus arteriosus hemodynamics in very premature infants treated with poractant alfa or beractant

Respiratory distress syndrome (RDS) and patent ductus arteriosus (PDA) are common co-morbidities in very premature infants. RDS requiring mechanical ventilation is treated with intratracheal surfactant. However, the administration of intratracheal surfactant may have both direct and indirect hemodynamic effects on PDA. Exogenous surfactant therapy, for example, may increase shunting across PDAs following rapid decreases in pulmonary vascular resistance. However, further evidence on this issue is still required. Beractant and poractant alpha are the two most commonly used modified animal-derived surfactants in the United States and are characterized by different rapidity of onset and duration of action. On this basis, an American group has conducted a randomized study to compare the hemodynamic effects of poractant alpha and beractant in premature infants <30 weeks’GA. A subgroup of 16 patients with severe RDS, treated with a second dose of surfactant, had echocardiographical assessments before and 20 to 30 min after the second dose of surfactant. In total, 25 infants were randomized to poractant alfa (27.1±1.6 weeks, birth weight 930±231 g) and 25 were assigned to beractant (26.7±1.7 weeks, birth weight 898±282 g) Clinically significant PDA was diagnosed and treated (with indomethacin or surgical ligation) in 8 of 25 (32%) patients treated with poractant alfa and in 19 of 25 (76%) of subjects in the beractant group (P=0.002). Indomethacin treatment was initiated slightly earlier (3.4±2.5 days) in the poractant alfa group than in the beractant group (5.1±4.9 days; P=0.038). Right ventricle pressure/systolic arterial pressure ratio in the first week was lower in patients on poractant alfa (64±20%) than in those receiving beractant (78±26%; P=0.048). Following a second dose of surfactant, neither poractant alfa nor beractant changed PDA flow. These hemodynamic observations were associated with less requirement for respiratory support in the poractant alfa group, which allowed for an earlier extubation (13 of 25 at 48 h and 15 of 25 at 72 h), than in the beractant group (6 of 25 at 48 h; P=0.044; 8 of 25 at 72 h, P=0.049). In conclusion, very premature infants on poractant alfa had a significantly lower number of PDAs requiring medical or surgical treatment than infants treated with beractant. The differences in PDA treatment and hemodynamics were also associated with a differential effect on respiratory support. In fact, the infants treated with poractant alfa required less mechanical ventilatory support than those treated with beractant. Neither poractant alfa nor beractant had direct hemodynamic effects on PDAs or PDA hemodynamics following the second surfactant dose in infants with severe RDS. It may be possible to speculate that the difference in PDAs was due to an indirect differential effect of poractant alfa and beractant on pulmonary function and associated PDA closure, even if further studies are required to confirm this finding.

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