Predicting extubation failure in preterm infants using lung ultrasound: a diagnostic accuracy study.

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.

Speed of lung inflation at birth influences the initiation of lung injury in preterm lambs.

Gas flow is fundamental for driving tidal ventilation and thus the speed of lung motion, but current bias flow settings to support the preterm lung after birth are without an evidence base. We aimed to determine the role of gas bias flow rates to generate positive pressure ventilation in initiating early lung injury pathways in the preterm lamb. Using slower speeds to inflate the lung during tidal ventilation (gas flow rates 4-6 L/min) did not impact lung mechanics, mechanical power or gas exchange compared to those currently used in clinical practice (8-10 L/min). Speed of pressure and volume change during inflation were faster with higher flow rates. Lower flow rates resulted in less bronchoalveolar fluid protein, better lung morphology and fewer detached epithelial cells. Overall, relative to unventilated fetal controls, there was greater protein change using 8-10 L/min, which was associated with enrichment of acute inflammatory and innate responses. Slowing the speed of lung motion by supporting the preterm lung from birth with lower flow rates than currently used clinically resulted in less lung injury without compromising tidal ventilation or gas exchange.

Plasma Proteome Profiles Associated with Early Development of Lung Injury in Extremely Preterm Infants.

The biological mediators which initiate lung injury in extremely preterm infants during early postnatal life remain largely unidentified, limiting opportunities for early treatment and diagnosis. This exploratory study used SWATH-mass spectrometry to identify bronchopulmonary dysplasia (BPD)-specific changes in protein abundance in plasma samples obtained in the first 72 hours of life from extremely preterm infants and bioinformatic analysis to identify BPD-related biological categories and pathways. Lasty, binary logistic regression analysis was used to test the BPD predictive potential of a base model alone (gestational age, birth weight, sex) and with the protein biomarker added, with bootstrap resampling used to internally validate protein predictors and adjust for overoptimism. We observed disturbance of key processes including coagulation, complement activation, development and extracellular matrix organisation in the first days of life in extremely preterm infants who were later diagnosed with BPD. In the BPD prediction analysis, 49 plasma proteins were identified which when each singularly was combined with birth characteristics had a C-index of 0.65-0.84 (optimism-adjusted C-index) suggesting predictive potential for BPD outcomes. Taken together, this study demonstrates that alterations in plasma proteins can be detected from 4 hours of age in extremely preterm infants who later develop BPD and that protein biomarkers when combined with three birth characteristics have the potential to predict BPD development within the first 72 hours of life.

Top 10 research priorities for congenital diaphragmatic hernia in Australia: James Lind Alliance Priority Setting Partnership.

OBJECTIVES: The Gaps in the Congenital Diaphragmatic Hernia (CDH) Journey Priority Setting Partnership (PSP) was developed in collaboration with CDH Australia, James Lind Alliance (JLA) and the Murdoch Children's Research Institute to identify research priorities for people with CDH, their families and healthcare workers in Australasia. DESIGN: Research PSP in accordance with the JLA standardised methodology. SETTING: Australian community and institutions caring for patients with CDH and their families. PATIENTS: CDH survivors, families of children born with CDH (including bereaved) and healthcare professionals including critical care physicians and nurses (neonatal and paediatric), obstetric, surgical, allied health professionals (physiotherapists, speech pathologists and speech therapists) and general practitioners. MAIN OUTCOME MEASURE: Top 10 research priorities for CDH. RESULTS: 377 questions, from a community-based online survey, were categorised and collated into 50 research questions. Through a further prioritisation process, 21 questions were then discussed at a prioritisation workshop where they were ranked by 21 participants (CDH survivors, parents of children born with CDH (bereaved and not) and 11 multidisciplinary healthcare professionals) into their top 10 research priorities. CONCLUSION: Stakeholders' involvement identified the top 10 CDH-related research questions, spanning from antenatal care to long-term functional outcomes, that should be prioritised for future research to maximise meaningful outcomes for people with CDH and their families.

Mechanical power made simple: validating a simplified calculation of mechanical power in preterm lungs.

BACKGROUND: The incidence of chronic lung disease is increasing, suggesting a need to explore novel ways to understand ventilator induced lung injury (VILI) in preterm infants. Mechanical power (MP) is a unifying measure of energy transferred to the respiratory system and a proposed determinant of VILI. The gold-standard method for calculating MP (geometric method) is not feasible in the clinical setting. This has prompted the derivation of simplified equations for calculating MP. OBJECTIVE: To validate the agreement between a simplified calculation of MP (MPSimple) and the true MP calculated using the geometric method (MPRef). METHODS: MPSimple and MPRef was calculated in mechanically ventilated preterm lambs (n = 71) and the agreement between both measures was determined using intraclass correlation coefficients (ICC), linear regression, and Bland-Altman analysis. RESULTS: A strong linear relationship (adjusted R2 = 0.98), and excellent agreement (ICC = 0.99, 95% CI = 0.98-0.99) between MPSimple and MPRef was demonstrated. Bland-Altman analysis demonstrated a negligible positive bias (mean difference = 0.131 J/min·kg). The 95% limits of agreement were -0.06 to 0.32 J/min·kg. CONCLUSIONS: In a controlled setting, there was excellent agreement between MPSimple and gold-standard calculations. MPSimple should be validated and explored in preterm neonates to assess the cause-effect relationship with VILI and neonatal outcomes. IMPACT STATEMENT: Mechanical power (MP) unifies the individual components of ventilator induced lung injury (VILI) and provides an estimate of total energy transferred to the respiratory system during mechanical ventilation. As gold-standard calculations of mechanical power at the bedside are not feasible, alternative simplified equations have been proposed. In this study, MP calculated using a simplified equation had excellent agreement with true MP in mechanically ventilated preterm lambs. These results lay foundations to explore the role of MP in neonatal VILI and determine its relationship with short and long term respiratory outcomes.

Endotracheal Tube Size Adjustments Within Seven Days of Neonatal Intubation.

BACKGROUND AND OBJECTIVES: Neonatal endotracheal tube (ETT) size recommendations are based on limited evidence. We sought to determine data-driven weight-based ETT sizes for infants undergoing tracheal intubation and to compare these with Neonatal Resuscitation Program (NRP) recommendations. METHODS: Retrospective multicenter cohort study from an international airway registry. We evaluated ETT size changes (downsizing to a smaller ETT during the procedure or upsizing to a larger ETT within 7 days) and risk of procedural adverse outcomes associated with first-attempt ETT size selection when stratifying the cohort into 200 g subgroups. RESULTS: Of 7293 intubations assessed, the initial ETT was downsized in 5.0% of encounters and upsized within 7 days in 1.5%. ETT downsizing was most common when NRP-recommended sizes were attempted in the following weight subgroups: 1000 to 1199 g with a 3.0 mm (12.6%) and 2000 to 2199 g with a 3.5 mm (17.1%). For infants in these 2 weight subgroups, selection of ETTs 0.5 mm smaller than NRP recommendations was independently associated with lower odds of adverse outcomes compared with NRP-recommended sizes. Among infants weighing 1000 to 1199 g: any tracheal intubation associated event, 20.8% with 2.5 mm versus 21.9% with 3.0 mm (adjusted OR [aOR] 0.62, 95% confidence interval [CI] 0.41-0.94); severe oxygen desaturation, 35.2% with 2.5 mm vs 52.9% with 3.0 mm (aOR 0.53, 95% CI 0.38-0.75). Among infants weighing 2000 to 2199 g: severe oxygen desaturation, 41% with 3.0 mm versus 56% with 3.5mm (aOR 0.55, 95% CI 0.34-0.89). CONCLUSIONS: For infants weighing 1000 to 1199 g and 2000 to 2199 g, the recommended ETT size was frequently downsized during the procedure, whereas 0.5 mm smaller ETT sizes were associated with fewer adverse events and were rarely upsized.