Parenteral nutrition (PN) preparations form oxidants when exposed to light. These free radicals have been attributed to the development of bronchopulmonary disease (BPD), retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC) and increased mortality in infants. Oxidant imbalance may also contribute to the development of PN-associated cholestasis. There are limited data regarding the effect of light-protection of PN on neonatal PN-associated cholestasis.
The primary outcome of this study was to evaluate the effect of PN light-protection on the development of cholestasis in preterm infants. Secondary outcomes included evaluation of PN light-protection on the incidence of feeding tolerance, BPD, ROP, NEC and mortality.
Our NICU implemented measures to protect PN from light using an amber bag to cover the PN solution, while leaving its administration (the tubing) and lipids exposed to light. In this retrospective study we reviewed patient charts before and after the implementation of this policy. A total of 50 infants were included: 25 patients in the no light-protection group and 25 in the light-protection group. Patient characteristics are described in Figure 1, panel A. To evaluate for PN-associated cholestasis, the analysis included direct and total bilirubin, liver enzymes, and triglycerides (Figure 1, panel B). The groups were compared using the Fisher's exact and Mann-Whitney U tests.
There was a statistically significant decrease in the rate of cholestasis (12 vs 3, p < 0.01), in the median peak direct bilirubin level (1.7 vs 0.9 mg/dL, p = 0.02) and total bilirubin level (4.1 vs 3.4, p = 0.05) in the light-protection group vs. no light-protection group (Figure1, panel B and Figure 2). Enteral feeds were initiated earlier in infants who received light-protected PN (day 6 vs 3, p = 0.004). There was a downward trend in the incidence of NEC (10 vs 4, p = 0.06) and AST/ALT levels (40 vs 33, p = 0.19 & 8 vs 6, p = 0.27 respectively) in the light-protection group when compared to the no light-protection group, however, these results were not statistically significant (Figure1, panel B). There was also a decrease in severe BPD and an increased in mild BPD after light-protection, but the overall BPD rate was the same. There was no significant difference in ROP or mortality.
Our study demonstrated that PN light-protection reduced the incidence of PN-associated cholestasis in premature infants. We are currently working on the phase two of this study and investigating additional benefit(s) of fully light protecting PN (bag, tubing, and lipids). We speculate that full light-protection of PN will further decrease free radical-related diseases in the neonatal population.
