<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 <.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 < .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>BACKGROUND: </strong>Conventional mechanical ventilation (CMV) of neonates has been used as a treatment of respiratory failure for over 30 years. While CMV facilitates gas exchange, it may simultaneously damage the lung. Positive end expiratory pressure (PEEP) has received less attention than other ventilation parameters when considering this balance of benefit and possible harm. While an appropriate level of PEEP may exert substantial benefits in ventilation, both inappropriately low or high levels may lead to harm. An appropriate level of PEEP for neonates may also be best achieved by an individualized approach.</p>
<p><strong>OBJECTIVES: </strong>1. To compare the effects of different levels of PEEP in preterm newborn infants requiring CMV for respiratory distress syndrome (RDS).2. To compare the effects of different levels of PEEP in preterm infants requiring CMV for bronchopulmonary dysplasia (BPD).3. To compare the effects of different methods for individualizing PEEP to an optimal level in preterm newborn infants requiring CMV for RDS.</p>
<p><strong>SEARCH METHODS: </strong>The search was performed in accordance with the standard search strategy for the Cochrane Neonatal Review Group. The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), Ovid MEDLINE, EMBASE, study references and experts were utilized for study identification.</p>
<p><strong>SELECTION CRITERIA: </strong>All randomized and quasi-randomized controlled trials studying preterm infants (less than 37 weeks gestational age) requiring CMV with endotracheal intubation and undergoing randomization to either different PEEP levels (RDS or BPD) or two or more alternative methods for individualizing PEEP levels (RDS only) were included. Cross-over trials were included but we limited the findings to those in the first cross-over period.</p>
<p><strong>DATA COLLECTION AND ANALYSIS: </strong>Data collection and analysis were performed in accordance with the recommendations of the Cochrane Neonatal Review Group.</p>
<p><strong>MAIN RESULTS: </strong>An initial evaluation identified 10 eligible articles. Ultimately, a single study met our inclusion criteria. The study addressed the effects of different levels of PEEP in preterm newborn infants requiring CMV for RDS. Only short term physiologic measures were reported. All results were limited to a small sample size without statistically significant results. No trials addressing the effect of PEEP in infants with BPD or strategies to individualize the management of PEEP were identified.</p>
<p><strong>AUTHORS' CONCLUSIONS: </strong>There is insufficient evidence to guide selection of appropriate PEEP levels for RDS or CMV. There is a need for well designed clinical trials evaluating the optimal application of this important and frequently applied intervention.</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>
<p>Continuous positive airway pressure (CPAP) has been used for respiratory support in premature infants for more than 40 years and is now a cornerstone of modern neonatal care. Clinical research on CPAP has primarily focused on understanding which devices and pressure sources best implement this therapy. In contrast, less research has examined the optimal duration over which CPAP is administered. We review this aspect of CPAP therapy.</p>