MT-CO1 and Patent ductus arteriosus: Roughly, there are four different management approaches for preterm infants with a PDA: (1) prophylactic treatment; (2) pre-symptomatic (‘early’) treatment; (3) symptomatic (‘late’) treatment and; (4) expectative management [9, 12].Prophylactic treatment consists of administration of COXi in all patients within a predefined patient group at a PNA less than 24 h.