Examination of changes in the breathing intolerance index to determine the respiratory support needs of very low birth weight infants
Abstract
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 If the BITI was less than 0.15, then we attempted to determine whether NRS could be withdrawn.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.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.
Open Research
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. The data that support the findings of this study are available from the corresponding author upon reasonable request.
