RESUMEN
BACKGROUND: The breathing intolerance index (BITI) is used to evaluate respiratory muscle tolerance. The higher the ratio of the inspiratory time to the total breathing time and the ratio of the tidal volume to the vital capacity, the more easily the respiratory muscles become fatigued. The BITI is high with chronic respiratory failure, and values of 0.15 or more indicate the need for assisted ventilation. OBJECTIVE: This study aimed to examine the changes in the BITI of very low birth weight infants (VLBWIs) and determine whether it is possible to use the BITI as an objective indicator of the timing of noninvasive respiratory support (NRS) withdrawal. METHODS: VLBWIs admitted to our neonatal intensive care unit between July 2020 and July 2022 under NRS at 36 weeks' postmenstrual age (PMA). If the BITI was less than 0.15, then we attempted to determine whether NRS could be withdrawn. RESULTS: Sixteen infants with a median gestational age and birth weight of 30.9 weeks and 1249 g, respectively, were eligible. The median PMA at the time of the first examination was 36.6 weeks. The BITI of two VLBWIs was less than 0.15. For 11 of the other VLBWIs, the BITI decreased over time to less than 0.15 at 39 weeks' PMA. After confirming that the BITI was less than 0.15, weaning from NRS was attempted. Weaning from NRS was possible except one VLBWI. CONCLUSION: The BITI can help evaluate respiratory tolerance and could be an objective indicator of the timing of NRS withdrawal.
RESUMEN
OBJECTIVE: To identify the incidence and characteristics of airway diseases in very low birth weight infants (VLBWIs). METHODS: A retrospective study of 214 inborn VLBWIs admitted to our NICU between April 2009 and March 2022 (approval no: 2023-0008). Neonatologists ourselves performed bronchoscopy to diagnose airway diseases. RESULTS: Symptomatic airway diseases were present in 36/214 (16.8%) of VLBWIs. Common airway diseases were tracheobronchomalacia (TBM) and pharyngomalacia. Infants with airway diseases had shorter gestational age, lower birth weight, more boys, and more moderate/severe bronchopulmonary dysplasia (BPD). Regarding treatment, more infants with airway diseases required intubation were intubated longer, used more dexamethasone, were on ventilators and oxygen longer, and were hospitalized longer. CONCLUSION: We found that VLBWIs were more frequently complicated with airway diseases, especially TBM. We also observed many pharyngeal lesions, which have not been previously reported. Intensity of prematurity, BPD, and the need for stronger respiratory management were risks for airway diseases. In VLBWIs, bronchoscopy should be actively performed because airway diseases are important complications.