Treatment of respiratory distress syndrome in premature infants with continuous positive airway pressure (CPAP) preserves surfactant and keeps the lung open but is insufficient in severe surfactant deficiency. Traditional surfactant administration is related to short periods of positive pressure ventilation and implies the risk of lung injury. CPAP with surfactant but without any positive pressure ventilation may work synergistically. This randomized trial investigated a less invasive surfactant application protocol (LISA).OBJECTIVE To test the hypothesis that LISA increases survival without bronchopulmonary dysplasia (BPD) at 36 weeks' gestational age in extremely preterm infants. DESIGN, SETTING, AND PARTICIPANTSThe Nonintubated Surfactant Application trial was a multicenter, randomized, clinical, parallel-group study conducted between April 15, 2009, and March 25, 2012, in 13 level III neonatal intensive care units in Germany. The final follow-up date was June 21, 2012. Participants included 211 of 558 eligible (37.8%) spontaneously breathing preterm infants born between 23.0 and 26.8 weeks' gestational age with signs of respiratory distress syndrome. In an intention-to-treat design, infants were randomly assigned to receive surfactant either via a thin endotracheal catheter during CPAP-assisted spontaneous breathing (intervention group) or after conventional endotracheal intubation during mechanical ventilation (control group). Analysis was conducted from September 6, 2012, to June 20, 2013.INTERVENTION LISA via a thin catheter. MAIN OUTCOMES AND MEASURESSurvival without BPD at 36 weeks' gestational age. RESULTSOf 211 infants who were randomized, 104 were randomized to the control group and 107 to the LISA group. Of the infants who received LISA, 72 (67.3%) survived without BPD compared with 61 (58.7%) of those in the control group. The reduction in absolute risk was 8.6% (95% CI, −5.0% to 21.9%; P = .20). Intervention group infants were less frequently intubated (80 infants [74.8%] vs 103 [99.0%]; P < .001) and required fewer days of mechanical ventilation. Significant reductions were seen in pneumothorax (5 of 105 intervention group infants [4.8%] vs 13 of 103 12.6%]; P = .04) and severe intraventricular hemorrhage (11 infants [10.3%] vs 23 [22.1%]; P = .02), and the combined survival without severe adverse events was increased in the intervention group (54 infants [50.5%] vs 37 [35.6%]; P = .02; absolute risk reduction, 14.9; 95% CI, 1.4 to 28.2).CONCLUSIONS AND RELEVANCE LISA did not increase survival without BPD but was associated with increased survival without major complications. Because major complications are related to lifelong disabilities, LISA may be a promising therapy for extremely preterm infants.

Relative hyperoxia is a condition frequently encountered in premature infants, either spontaneously or during treatment in the Neonatal Intensive Care Unit. The effects of high inspiratory oxygen concentrations on immature brain cells and their signaling cascades are largely unknown. The aim of the study was to investigate the effect of hyperoxia on the amount and topographic distribution of iNOS-expression (inducible nitric oxide synthase) in the immature rat brain, and to localize hyperoxia-induced formation of peroxynitrite as a potential marker of cellular damage to immature cerebral structures. Seven-day-old Wistar rat pups were exposed to Ͼ80% oxygen for 24 h and were then transcardially perfused. Following paraformaldehyde fixation, brains were paraffin-embedded and immunohistochemically stained for iNOS and nitrotyrosine. iNOS protein was quantified by Western blot; iNOS mRNA expression was studied by RT-PCR. Total brain iNOS mRNA was up-regulated, demonstrating a peak at 6 h following the onset of hyperoxia. Immunohistochemical staining was predominantly observed in microglial cells of hippocampus and frontal cortex with some iNOS reactivity in endothelial and perivascular cells. Nitrotyrosine staining was positive in apical dendrites of neurons in the frontal cortex. The role of NO has been subject of numerous investigations during recent years. This applies to its function as a gaseous messenger molecule and to its vasodilative properties. NO is released by hydroxylation of nitrogen at the guanidino group of L-arginine, a reaction which is catalyzed by the enzyme NO synthase (NOS). At least three isoforms of NOS are known at the moment, two constitutive forms (endothelial NOS and neuronal NOS) and the inducible form (iNOS). The latter is induced by bacteria and cytokines. NO concentrations produced by iNOS are much higher than those generated by constitutive NOS (1), and have been shown to exert antimicrobial effects against some bacterial pathogens in vitro (2).As soon as NO is generated in the target cell (cancer cell, parasite), binding at copper and iron containing proteins takes place (3). As a result copper and iron are released and, in combination with oxygen, toxic radicals are formed. This is referred to as "massive oxidative injury" and requires the expression of iNOS leading to the production of huge amounts of NO, whereas low levels of NO synthesized by the constitutive forms of NOS (eNOS, nNOS) act as a signal molecule (4). Thus, the concentration of NO determines its biologic effect upon neighboring cells and tissues. The reaction products of nitrogen and oxygen include the strong oxidant peroxyni-

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