<p>Reducing the risk of primary noninvasive ventilation failure in extremely low birthweight infants is linked to reducing bronchopulmonary dysplasia. In a secondary analysis of randomized data, we identified that failure rates and time to failure were similar for nasal intermittent positive pressure ventilation vs nasal continuous positive airway pressure.</p>

<p><strong>OBJECTIVE: </strong>To test the hypothesis that significant positive end-expiratory pressure (PEEP) level variation exists between neonatal centers.</p>

<p><strong>STUDY DESIGN: </strong>We performed a secondary analysis cohort study of the Nasal Intermittent Positive-Pressure Ventilation trial. Our study population was extremely low birth weight infants requiring mechanical ventilation within 28 days of life. The exposure was neonatal center; 34 international centers participated in the trial. Subjects from centers with fewer than 5 eligible cases were excluded. The main outcome was the maximal PEEP level used during the first course of mechanical ventilation. Infant characteristics judged a priori to directly influence clinical PEEP level selection and all characteristics associated with PEEP at P &lt;.05 in bivariable analyses were included with and without center in multivariable linear regression models. Variation in PEEP level use between centers following adjustment for infant characteristics was assessed.</p>

<p><strong>RESULTS: </strong>A total of 278 extremely low birth weight infants from 17 centers were included. Maximal PEEP ranged from 3 to 9 cm H2O, mean = 5.7 (SD = 0.9). Significant variation between centers remained despite adjustment for infant characteristics (P &lt; .0001). Further, center alone explained a greater proportion of the PEEP level variation than all infant characteristics combined.</p>

<p><strong>CONCLUSIONS: </strong>Marked variation in PEEP levels for extremely low birth weight infants exists between neonatal centers. Research providing evidence-based guidance for this important aspect of respiratory care in preterm infants at high risk of lung injury is needed.</p>

<p><strong>TRIAL REGISTRATION: </strong>ClinicalTrials.govNCT00433212.</p>

<p><strong>RATIONALE: </strong>Currently used definitions of bronchopulmonary dysplasia (BPD) lack a continuous measure of disease severity.</p>

<p><strong>OBJECTIVES: </strong>To determine if an indirect measure of V./Q. mismatch is reliable when simplified to facilitate more widespread use for grading disease severity in BPD at 36 weeks postmenstrual age.</p>

<p><strong>METHODS: </strong>We used prospectively collected data from 32 preterm infants undergoing an oxygen reduction test at 36 weeks postmenstrual age to perform a simplified indirect assessment of V./Q. mismatch for each infant. Independent raters applied the model, and interrater reliability for a quantitative measure of mismatch was measured by intraclass correlation coefficient. A receiver operating characteristic curve evaluated the impact of increasing degrees of V./Q. mismatch on diagnosing BPD as defined by oxygen reduction test failure.</p>

<p><strong>MEASUREMENTS AND MAIN RESULTS: </strong>Concordance for the quantitative measure of V./Q. mismatch between independent raters improved from 0.72 (confidence interval [CI], 0.48-0.86) to 0.93 (CI, 0.87-0.96) after refinement of instructions for applying the simplified model. Higher degrees of mismatch were increasingly predictive of oxygen reduction test failure, with a receiver operating characteristic curve analysis area under the curve of 0.83 (CI, 0.68-0.99; P = 0.03).</p>

<p><strong>CONCLUSIONS: </strong>A simplified indirect measure of V./Q. mismatch for diagnosing and grading disease severity in BPD has high reliability and can be performed with data obtained during a standard oxygen reduction test. This should facilitate more widespread investigation of this model as a technique for characterizing BPD severity.</p>