There is uncertainty among neonatologists regarding the most efficacious form of surfactant for the rescue treatment of RDS of the premature. A randomized blinded multicenter trial was performed among 10 level 3 Canadian neonatal units comparing b with E. Ventilated prematures were stratified in<750 g (b=92, E=88) and 750-1250 g (b=224, E=231) and randomized at a PaO2/PAO2 ratio (a/A) of <0.22. Up to 4 doses were administered intratracheally. The study was terminated when the 750-1250 g group reached the projected sample size.

There was no difference in the primary outcome, intact cardiopulmonary survival at 36 weeks gestational age for either weight group. In the 750-1250 g group, significantly more babies treated with b were alive at discharge(p=0.035), had less air leaks (p=0.0025), and required less days of supplemental oxygen (p=0.023) when compared to E treated babies. At 8 hours following the first dose of surfactant the FiO2, mean airway pressure (MAP), and oxygenation index (OI = MAP × FiO2 × 100/PaO2) were significantly lower and the a/A higher in b treated babies in both weight groups (Table). Seventy-two hours following the first dose of surfactant, only the FiO2 was significantly lower in the b treated 750-1250 g group (p=0.0028). The total number of doses was not significantly different. There was no significant difference in the incidence of total intraventricular hemorrhage (IVH) or severe grade III-IV IVH/periventricular leukomalacia between b 11/92 (12%) or E 13/88 (15%) treated babies in either weight group. No infants treated with b died as a result of pulmonary hemorrhage 0/92 (0%) compared with 7 treated with E 7/86 (8.2%), p=0.016. Long term follow-up data will be available.

Table 1 No caption available.
Full size table

Although the primary outcome was not different among b and E, the significant improvement in secondary outcomes suggests that b is a more effective surfactant for the rescue treatment of RDS.