Ultrasonographic assessment of diaphragmatic function in preterm infants on Non-Invasive Neurally Adjusted Ventilatory Assist (NIV-NAVA) compared to Nasal Intermittent Positive-Pressure Ventilation (NIPPV): A prospective observational study

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 (DT exp ), end of inspiration (DT ins ), 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 4 th Neonatal Research Day- Toronto, Canada on April, 2022 as an oral presentation.