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BACKGROUND Our understanding of the normative concentrations of urine biomarkers in premature neonates is limited. METHODS We evaluated urine from 750 extremely low gestational age (GA) neonates without severe acute kidney injury (AKI) to determine how GA affects ten different urine biomarkers at birth and over the first 30 postnatal days. Then, we investigated if the urine biomarkers changed over time at 27, 30, and 34 weeks postmenstrual age (PMA). Next, we evaluated the impact of sex on urine biomarker concentrations at birth and over time. Finally, we evaluated if urine biomarkers were impacted by treatment with erythropoietin (Epo). RESULTS We found that all ten biomarker concentrations differ at birth by GA and that some urine biomarker concentrations increase, while others decrease over time. At 27 weeks PMA, 7/10 urine biomarkers differed by GA. By 30 weeks PMA, 5/10 differed, and by 34 weeks PMA, only osteopontin differed by GA. About half of the biomarker concentrations differed by sex, and 4/10 showed different rates of change over time between males vs. females. We found no differences in urine biomarkers by treatment group. CONCLUSIONS The temporal patterns, GA, and sex differences need to be considered in urine AKI biomarker analyses. IMPACT Urine biomarker concentrations differ by GA at birth. Some urine biomarkers increase, while others decrease, over the first 30 postnatal days. Most urine biomarkers differ by GA at 27 weeks PMA, but are similar by 34 weeks PMA. Some urine biomarkers vary by sex in premature neonates. Urine biomarkers did not differ between neonates randomized to placebo vs. Epo.

Aerosolized KL 4 Surfactant Improves Gas Exchange and Survival in Spontaneously Breathing Piglets with HCL-Induced Acute Lung Injury

Premature infants are subjected to adverse effects of intubation to benefit from surfactant. We hypothesized that administration of surfactant through a laryngeal mask airway (LMA) is as effective as administration through an endotracheal tube (ETT) and that time and physiologic changes during instrumentation will be less in the LMA group. This study is a randomized, controlled trial using newborn pigs. Lung injury was induced via surfactant washout. Animals were randomized into groups: 1) LMA placed, no surfactant administered (control; n = 8); 2) surfactant via an LMA (LMA group; n = 8); and 3) surfactant via an ETT (ETT group; n = 8). We demonstrated that partial pressure of oxygen in arterial blood (Pao2) levels of the LMA and ETT groups were not statistically different. Time for successful placement of LMA was 19 ± 1 s versus ETT 123 ± 35 s (mean ± SEM); number of attempts for successful LMA placement was 1.1 (1-2) versus ETT 1.9 (1-7) [mean (range)]. Administration of surfactant via an LMA compared with an ETT resulted in similar improvements in oxygenation. Placement of the device required less time and fewer attempts. These data suggest that further study in human neonates is justified. If proven effective, some infants with respiratory distress may be able to receive surfactant while avoiding intubation.