Objectives: To identify the predictors of successful first trial off nasal continuous positive airway pressure (nCPAP).Methods: A retrospective cohort study of infants ≤29 weeks' gestation who required nCPAP for >24 h was conducted. Logistic regression was used to detect predictors for successful trial off nCPAP. Statistical analysis was performed using the SAS software.Results: A total of 727 infants were included in the analysis. Infants who were successful in their first trial off nCPAP (n = 313) were of higher gestational age (GA) and birth weight (BW), as well as a higher proportion of female infants, compared with those who were not successful (p < 0.01). When stratified by GA, a negative correlation was noted between GA and postmenstrual age at successful trial off nCPAP or high flow nasal cannula (HFNC) (r = 0.45, p < 0.01). Logistic regression analysis showed that GA (odds ratio [OR] 1.13, 95% confidence interval [CI] [1.03-1.24], p = 0.01) and percentage of time spent with an oxygen saturation over 89% in the 24 h preceding the trial off nCPAP (OR 1.08,], p = 0.00) were independent predictors for successful trial off nCPAP. Conclusion:Successful trial off nCPAP or HFNC in preterm infants is significantly associated with higher GA, BW, female gender, and the specific oxygen saturation histogram in the preceding 24-h period.

Purpose of the study: NIV-NAVA mode for respiratory support in preterm infants is not well-studied. The aim of this study was to describe diaphragmatic function, diaphragmatic excursion (DE) and thickness fraction (DTF), in preterm infants < 30 weeks’ gestation supported by NIV-NAVA compared to NIPPV using bedside ultrasonography. Methods: In this consecutive prospective study, DE, diaphragmatic thickness at end of expiration (DTexp), end of inspiration (DTins), and DTF were assessed using bedside ultrasound. Lung aeration evaluation using lung ultrasound score (LUSs) was performed for the two groups. Diaphragmatic measurements and LUSs were compared for the 2 groups (NIV-NAVA group versus NIPPV group). Statistical analyses were conducted using SPSS software version 22. Results: Out of 70 infants evaluated, 40 were enrolled. Twenty infants were on NIV-NAVA (mean [SD] study age of 25.7 [0.9] weeks) and 20 infants were on NIPPV (mean [SD] study age of 25.1 [1.4] weeks p= 0.15). Baseline characteristics and respiratory parameters at the time of the scan, showed no significant difference between groups. DE was significantly higher in NIV-NAVA with a mean SD 4.7 (1.5) versus 3.5 (0.9) in NIPPV, p=0.007. Additionally, the mean (SD) of DTF for the NIV-NAVA group was 81.6 (30) vs 78.2 (27) for NIPPV group [p=0.71]. Both groups showed relatively high LUSs but no significant difference between groups [12.8 (2.6) vs 12.6 (2.6) p=0.8]. Conclusion: Preterm infants managed with NIV-NAVA showed significantly higher DE compared to those managed on NIPPV. Longitudinal studies to assess diaphragmatic function over time are needed. Trial Registry: Clinicaltrials.gov (NCT05079412) Date of registration 09/30/2021 Abstract publication/presentation: Portions of this paper were presented at the Pediatric Academic Society (PAS) meeting in Denver, USA, May 2022 as poster presentation as well as at the 4th Neonatal Research Day- Toronto, Canada on April, 2022 as an oral presentation.

NIV-NAVA mode for respiratory support in preterm infants is not well-studied. This study aimed to describe the diaphragmatic function, diaphragmatic excursion (DE), and thickness fraction (DTF), in preterm infants < 30 weeks’ gestation supported by NIV-NAVA compared to NIPPV using bedside ultrasonography. In this consecutive prospective study, DE, diaphragmatic thickness at end of expiration (DT exp ), end of inspiration (DT ins ), and DTF were assessed using bedside ultrasound. Lung aeration evaluation using lung ultrasound score (LUS) was performed for the two groups. Diaphragmatic measurements and LUS were compared for the 2 groups (NIV-NAVA group versus NIPPV group). Statistical analyses were conducted using the SPSS software version 22. Out of 70 infants evaluated, 40 were enrolled. Twenty infants were on NIV-NAVA and 20 infants on NIPPV with a mean [SD] study age of 25.7 [0.9] weeks and 25.1 [1.4] weeks respectively ( p = 0.15). Baseline characteristics and respiratory parameters at the time of the scan showed no significant difference between groups. DE was significantly higher in NIV-NAVA with a mean SD of 4.7 (1.5) mm versus 3.5 (0.9) mm in NIPPV, p = 0.007. Additionally, the mean (SD) of DTF for the NIV-NAVA group was 81.6 (30) % vs 78.2 (27) % for the NIPPV group [ p = 0.71]. Both groups showed relatively high LUS but no significant difference between groups [12.8 (2.6) vs 12.6 (2.6), p = 0.8]. Conclusion : Preterm infants managed with NIV-NAVA showed significantly higher DE compared to those managed on NIPPV. This study raises the hypothesis that NIV-NAVA could potentially improve diaphragmatic function due to its synchronization with patients’ own breathing. Longitudinal studies to assess diaphragmatic function over time are needed. Trial registry : Clinicaltrials.gov (NCT05079412). Date of registration September 30, 2021. What is Known: • NIV-NAVA utilizes diaphragmatic electrical activity to provide synchronized breathing support. • Evidence for the effect of NIV-NAVA on diaphragmatic thickness fraction (DTF) and excursion (DE) is limited. What is New: • Ultrasonographic assessment of diaphragmatic function (DTF and DE) is feasible. • In preterm infants, DE was significantly higher in infants supported with NIV-NAVA compared to those supported with NIPPV.