261 - The Effect of Bethanechol on Tracheobronchomalacia in Preterm Infants with Bronchopulmonary Dysplasia: A Retrospective Cohort Study

Poster Number: 261
Publication Number: 261.34

Charles P. Pugh, Arkansas Children's Hospital, Little Rock, AR, United States; Chary Akmyradov, Arkansas Children's Hospital, Little Rock, AR, United States; Sherry Courtney, University of Arkansas for Medical Sciences College of Medicine, Little Rock, AR, United States; Amit Agarwal, ach, Little Rock, AR, United States; Angela L. Chandler, University of Arkansas for Medical Sciences College of Medicine, Little Rock, AR, United States; David Matlock, University of Arkansas for Medical Sciences, Little Rock, AR, United States

Background: Tracheobronchomalacia (TBM) is characterized by airway collapse leading to prolonged mechanical ventilation, increased caloric needs, and prolonged hospitalization. Bethanechol, a muscarinic agonist, has demonstrated improvement in trachealis tone in animal models, but no trials have studied efficacy in infants. A pulmonary severity score (PSS) has been developed as an assessment tool to compare infant lung disease. A lower PSS reflects improved respiratory status.

Objective: To examine the effect of bethanechol on PSS in infants with TBM.

Design/Methods: This retrospective cohort study included 33 subjects (11 cases, 22 controls) between 2017–2022. Cases were matched with controls who did not receive bethanechol. TBM was diagnosed by dynamic computography demonstrating > 50% cross-sectional diameter collapse. PSS was recorded from 40 to 55 weeks post-menstrual age for both groups with each case having a different bethanechol start day. Case-control 1:2 matching was performed based on birth gestational age, sex, severity of TBM, severity of bronchopulmonary dysplasia and respiratory support. The primary outcome was the effect of bethanechol on mean PSS. Secondary outcomes included changes in bradycardia/desaturation events, sedation, and respiratory rate.

Results: Table 1 demonstrates a 21% decrease in PSS comparing cases to themselves pre- and post-bethanechol treatment (p=0.002 by paired t-test). A decrease in PSS was seen in all cases with a larger decrease in cases started on bethanechol at an earlier post-menstrual age (Figure 1). An analysis to examine whether cases’ PSS decreased by at least 10% more than controls’ pre- and post-bethanechol initiation demonstrated a trend not reaching statistical significance (odds ratio 4.6; 95% CI 0.91, 23; p=0.06). However, table 1 demonstrates a 22% lower mean PSS in cases compared to controls at the post-menstrual age at which cases had been treated with bethanechol for 10 days (p=0.02 by paired t-test). Matched differences (controls’ PSS – cases’ PSS) demonstrated greater mean PSS difference post-bethanechol compared to pre-bethanechol 0.17, (95% CI 0.05, 0.29) by paired t-test (p=0.009) (Figure 2). Differences in secondary outcomes were not statistically different though all trended lower in cases after bethanechol treatment (Table 1).

Conclusion(s): This study represents the first cohort study to examine respiratory outcomes in infants with TBM treated with bethanechol. PSS improved in infants treated with bethanechol as compared to those who were not treated. Future well-controlled trials are needed to evaluate the efficacy of this medication.