Reliability of a Noninvasive Measure of V./Q. Mismatch for Bronchopulmonary Dysplasia.

rationaleCurrently used definitions of bronchopulmonary dysplasia (BPD) lack a continuous measure of disease severity.

objectivesTo 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.

methodsWe 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. MEASUREMENTS AND MAIN

resultsConcordance 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).

conclusionsA 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.