Introduction: Pediatric Acute Respiratory Distress Syndrome (PARDS) is common in children < 2 years intubated for lower respiratory tract infections (LRTI), often termed bronchiolitis, and is associated with increased mortality and length of stay. Non-adherence to PALICC/ARDSNet PARDS guidelines is associated with poor outcomes in the general pediatric population but adherence rates in this younger population are largely unknown. Here, we describe adherence to recommendations for ventilator management in LRTI subjects with PARDS. Methods: We performed a sub-analysis of data from the Bronchiolitis And CO-detectioN (BACON) study, an IRB-approved international prospective observational study of critical bronchiolitis at 43 sites from 2019 to 2020. Inclusion criteria were age < 2 years, endotracheal intubation, and acute LRTI. Tidal volume (Vt) and PEEP adherence were determined according to PALICC/ARDSNet guidelines for subjects on conventional ventilation meeting PARDS criteria on day 1 post intubation. Chi squared and Wilcoxon rank sum were used to compare outcomes. Reasons for PEEP non-concordance were evaluated by univariate logistic regression. Data are shown as n (%), median (IQR) and OR (95%CI). Results: Of 518 subjects, 211 (41%) met PALICC criteria for PARDS (55% Mild, 36% Moderate, 9% Severe) on day 1 and were included. For the PARDS cohort, median age was 5 months, Vt 7.8, FiO2 0.45, and PEEP 8. Guideline concordance was 65% for Vt and 56% for PEEP, decreasing for each as severity increased. Logistic regression showed each 1-point increase in OI gave an OR for PEEP adherence of 0.85 (0.77,0.94). Also associated with PEEP non-adherence was increasing age (0.95) for each month increase, wheeze at presentation (0.45), and day 1 use of vasoactives (0.35). Adherence to PEEP guidelines was associated with decreased mortality (0.8% vs 16%, p< 0.0001), shorter mechanical ventilation (MV) duration (159 vs 203 hours, p=0.003), and ICU length of stay (LOS) (10.1 vs 12.9 days, p=0.018). Vt guideline adherence was not associated with any outcome. Conclusions: Non-adherence to PALICC PARDS guidelines in young children diagnosed with bronchiolitis and LRTI is common and increases with PARDS severity. PEEP non-adherence in this cohort is associated with increased mortality, MV duration and ICU LOS.