Objective To determine the accuracy of pre-extubation lung ultrasound (LUS) to predict reintubation in preterm infants born <32 weeks’ gestation.

Design Prospective diagnostic accuracy study.

Setting Two neonatal intensive care units.

Methods Anterior and lateral LUS was performed pre-extubation. The primary outcome was the accuracy of LUS scores (range 0–24) to predict reintubation within 72 hours. Secondary outcomes were accuracy in predicting (1) reintubation within 7 days, (2) reintubation stratified by postnatal age and (3) accuracy of lateral imaging only (range 0–12). Pre-specified subgroup analyses were performed in extremely preterm infants born <28 weeks’ gestation. Cut-off scores, sensitivities and specificities were calculated using receiver operating characteristic analysis and reported as area under the curves (AUCs).

Results One hundred preterm infants with a mean (SD) gestational age of 27.4 (2.2) weeks and birth weight of 1059 (354) g were studied. Thirteen were subsequently reintubated. The AUC (95% CI) of the pre-extubation LUS score for predicting reintubation was 0.63 (0.45–0.80). Accuracy was greater in extremely preterm infants: AUC 0.70 (0.52–0.87) and excellent in infants who were <72 hours of age at the time of extubation: AUC 0.90 (0.77–1.00). Accuracy was poor in infants who were >7 days of age. Lateral imaging alone demonstrated similar accuracy to scanning anterior and lateral regions.

Conclusions In contrast to previous studies, LUS was not a strong predictor of reintubation in preterm infants. Accuracy is increased in extremely preterm infants. Future research should focus on infants at highest risk of extubation failure and consider simpler imaging protocols.

Trial registration number Australian New Zealand Clinical Trials Registry: ACTRN12621001356853.

Individual patient data collected during the study and the statistical analysis will be available beginning 3 months and ending 23 years after article publication to researchers who provide a methodologically sound proposal with approval by the investigators local independent review committee. Data will be available for analysis to achieve aims in the approved proposal. Proposals should be directed to Arun.Sett@thewomens.org.au; to gain access, data requestors will need to sign a data access or material transfer agreement approved by the Newborn Research Centre, The Royal Women’s Hospital, Melbourne, Australia.