Supplementary Material for: A Nomogram for Predicting Extubation Failure in Preterm Infants with Gestational Age Less than 29 Weeks

<b><i>Introduction:</i></b> How to avoid reintubations in prematurity remains a hard nut. This study aimed to develop and validate a nomogram for predicting extubation failure in preterm infants who received different modes of noninvasive ventilation as post-extubation support. <b><i>Methods:</i></b> This was a secondary analysis of pre-existing data from a large multicenter RCT combined with a multicenter retrospective investigation in three tertiary referral NICUs in China. The training cohort consisted of extubated infants from the RCT and the validation cohort included neonates admitted to the three NICUs in the last 5 years. The nomogram was developed through univariate and multivariate logistic regression analyses of peri-extubation clinical variables. <b><i>Results:</i></b> A total of 432 and 183 preterm infants (25 weeks ≤ gestational age [GA] &lt;29 weeks) were, respectively, included in the training cohort and the validation cohort. Lower birth weight, lower Apgar 5-min score, lower postmenstrual age at extubation, lower PO₂ and higher PCO₂ before extubation, and continuous positive airway pressure rather than nasal intermittent positive pressure ventilation or noninvasive high-frequency oscillatory ventilation after extubation were associated with higher risks of extubation failure (<i>p</i> &lt; 0.05), on which the nomogram was established. In both the training cohort and the validation cohort, the nomogram demonstrated good predictive accuracy (area under the receiver operating characteristic curve = 0.744 and 0.826); the Hosmer-Lemeshow test (<i>p</i> = 0.192 and 0.401) and the calibration curve (<i>R</i>² = 0.195 and 0.307) proved a good fitness and conformity; and the decision curve analysis showed significant net benefit at the best threshold (<i>p</i> = 0.201). <b><i>Conclusion:</i></b> This nomogram could serve as a good decision-support tool when predicting extubation failure in preterm infants with GA less than 29 weeks.