Objective        Pulmonary hemorrhage (PH) is considered as one of severe adverse events associated with surfactant therapy in the treatment of neonatal respiratory distress syndrome (NRDS). In this multicenter retrospe

ctively study

we wish to find the timing of initial surfactant administration in order to reduce the incidence of PH.       Methods        Clinical data of 453 NRDS cases treated by calf pulmonary surfactant (CPS) in the Department of Neonatology out of 22 hospitals during May 2008 to June 2009 were collected and reviewed. These neonates were divided into 3 groups: severe NRDS cases treated by CPS and conventional mechanical ventilation(CMV) (group 1)

mild NRDS cases treated with CPS and CMV (group 2)

and mild RDS cases treated with CPS and nasal continuous positive airway pressure (nCPAP) (group 3). Postnatal hours 1

2

3

4

5

6

7 and 8 were selected as cutoff times

and the incidence of PH at these time points were analyzed. The incidence of PH between group 2 and 3 were also compared.       Results        For severe NRDS cases

significant differences in the incidence of PH were found when postnatal hours 4

5

6

7 and 8 were selected as the cutoff time (

P

<

0.05). For mild NRDS cases

the incidence of PH was significantly lower in the neonates receiving CPS within 5 h after birth than those beyond 5 h (3.2%

vs

9.7%

P

<

0.05). Postnatal hour 5 was selected as the cutoff time for mild NRDS cases

with the incidence of PH obviously lower found in the neonates treated by nCPAP than those by CMV (0.3%

vs

6.5%

P

<

0.05).       Conclusion        Postnatal hour 5 is identified as the timing of initial CPS administration to reduce the incidence of PH. For mild NRDS

the incidence of PH is greatly decreased when initial surfactant administration performed within 5 h after birth followed by nCPAP.