Background: Weaning process from mechanical ventilation (MV) in children with tracheostomy and long-term mechanical ventilation (LTMV) constitutes a challenging process due to diagnosis heterogeneity and significant variability in the clinical condition. We aimed to evaluate the physiological response during the first attempt of a Spontaneous Breathing trial (SBT) and to compare variables in subjects who failed and succeeded the SBT.

Methods: Prospective observational study in tracheostomized children with LTMV admitted to the Hospital Josefina Martinez, between 2014-2020. Cardiorespiratory variables such as breathing pattern, use of accessory respiratory muscles, HR, RR, and SpO₂ were registered at baseline and throughout a 2-hour SBT with or without positive pressure depending on a SBT protocol. Comparison of demographic and ventilatory variables between groups was performed.

Results: 48 subjects were analyzed, median (p25-75) age of 20.5 (17-35) months,
60% male. Chronic lung disease was the primary diagnosis in 60% of subjects. Eleven (23%) of
total subjects failed the SBT (<2 h) with an average failure time of 69±29 minutes. Subjects
who failed the SBT had a significantly higher breathing frequency, HR, and ETCO₂ than
subjects who succeeded (p<.001). In addition, They had significantly shorter duration of MV before de SBT and higher proportion of unassisted SBT in comparison with success group.

Conclusion: Conducting an SBT to evaluate the tolerance and cardiorespiratory response in
tracheostomized children with LTMV is feasible. Time on MV before the first attempt and type of SBT (with or without positive pressure) could be associated with SBT failure.