<p><strong>OBJECTIVES: </strong>To measure between-center variation in loop diuretic use for infants developing severe bronchopulmonary dysplasia (BPD) in United States children's hospitals, and to compare mortality and age at discharge among infants from low versus high use centers.</p>

<p><strong>STUDY DESIGN: </strong>We performed a retrospective cohort study of preterm infants &lt;32 weeks gestational age developing severe BPD. The primary outcome was cumulative loop diuretic use, defined as the proportion of days with exposure between admission and discharge. Infant characteristics associated with loop diuretic use at P &lt; .10 were included in multivariable models to adjust for center differences in case-mix. Hospitals were ranked from lowest to highest in adjusted use, and dichotomized into low or high use centers. We then compared mortality and postmenstrual age at discharge between groups through multivariable analyses.</p>

<p><strong>RESULTS: </strong>We identified 3252 subjects from 43 centers. Significant variation between centers remained despite adjustment for infant characteristics, with use present in an adjusted mean range of 7.3% to 49.4% of days, p &lt; 0.0001. Mortality (adjusted odds ratio 0.98 [95% CI 0.62, 1.53], p = 0.92) and postmenstrual age at discharge (marginal mean [95% CI]: 47.3 [46.8 , 47.9] versus 47.4 [46.9, 47.9] weeks, p = 0.96) were similar in low and high use groups, respectively.</p>

<p><strong>CONCLUSIONS: </strong>Marked variation in loop diuretic use for infants developing severe BPD exists between US children's hospital, without an observed difference on mortality or discharge age. Research to provide evidence-based guidance for this common exposure is needed.</p>

<p><strong>OBJECTIVE: </strong>Examine the effect of off-label surfactant on mortality and morbidity in more mature and larger premature infants diagnosed with respiratory distress syndrome (RDS).</p>

<p><strong>STUDY DESIGN: </strong>Cohort study of premature infants born at 30-36 weeks, birth weight &gt; 2 kg, and a diagnosis of RDS. We compared the odds of mortality and morbidity between infants who were exposed vs unexposed to surfactant. We used a treatment effects model to balance covariates between groups.</p>

<p><strong>RESULTS: </strong>Of 54,964 included infants, 25,278 (46%) were exposed to surfactant. The frequency of mortality and morbidities were higher in the exposed group in unadjusted analyses. Following adjustment with a doubly robust treatment effects model, we found no significant treatment effect of surfactant on mortality or morbidity.</p>

<p><strong>CONCLUSION: </strong>Surfactant exposure is not associated with reduced or increased mortality or morbidity in more mature premature infants with RDS.</p>