The PaCO ( @ ) ( mmHg , @ mmHg = @ kPa ) , oxygen index ( OI ) at @-@ h , and FiO ( @ ) at @ h post-ventilation in BiPAP and SBiPAP groups were lower than that in NCPAP groups with significant difference ( @ @ and @ @ vs. @ @ , @ @ and @ @ vs. @ @ , @ @ and @ @ vs. @ @ ; F = @ , @ and @ ; P = @ , @ and @ , respectively ) .