Oxygen saturation to fraction of inspired oxygen ratio in preterm infants on routine parenteral nutrition with conventional or fish oil containing lipid emulsions

Introduction: The benefits of intravenous (IV) fish oil (FO), as a source of n-3 long-chain polyunsaturated fatty acids, on lung growth in preterm infants, remain controversial. Aim: To evaluate if IV FO improves lung growth in small preterm infants on routine parenteral nutrition (PN). Materials and Methods: We retrospectively reviewed prospectively collected data of preterm infants with a birth weight <1250 g who received routine PN from birth. We compared patients who received FO containing IV lipid emulsions with infants who received conventional emulsions (CNTR). The oxygen saturation (SpO2) to a fraction of inspired oxygen (FiO2) ratio (SFR) at 36 weeks (W) of gestation was chosen as the primary outcome variable to assess lung growth. Results: Four hundred and seventy-seven infants were studied: 240 received IV FO and 237 CNTR. While exposure to antenatal glucocorticoids was higher in IV FO group than in CNTR (95 vs 90%, P =.04), there were no differences in birth data, enteral and parenteral nutrition intakes, ventilator supports and drug therapies. The incidence of the most common complications of prematurity at 36 W was not different (bronchopulmonary dysplasia was 27 vs 21% in IV FO vs CNTR infants, P =.1). Weight gain from birth to 36 W was marginally, but significantly, higher (+0.5 g/kg/d, P =.03) in IV FO group vs CNTR. SFR increased from 32 W to 36 W in all study patients (P <.001). IV FO infants had significantly lower SpO2 from 33 W to 35 W (P <.001) and lower (worse) SFR at 36 W (432 ± 57 vs 444 ± 51, P =.026) compared to CNTR. Conclusion: Contrary to our hypothesis, the use of FO containing IV lipid emulsions for the routine PN of the preterm infant did not improve lung growth compared to the infants who received conventional IV lipid emulsions.