Study Measures and Data Collection
HFNC duration in hours was used as the primary outcome measure, while PICU LOS, hospital LOS, and continuous albuterol duration in hours were used as secondary outcome measures. Pre-intubation noninvasive ventilation (NIV) use (bi-level positive airway pressure), invasive mechanical ventilation (IMV) use, and 7-day PICU and hospital readmission rate were used as balancing measures. Analysis was conducted on data obtained from Virtual PICU Systems (VPS, Los Angeles, California). We used VPS to collect admission and discharge dates, age, sex, PRISM score, types of respiratory support, procedures (including intubation and ECMO cannulation). Data on race and ethnicity were collected from VPS but taken directly from the medical record (Cerner, North Kansas City, MO); race was defined by the National Institutes of Health (NIH) guidelines (21). We used Cerner to collect data on medications and other adjunctive therapies, including albuterol, magnesium sulfate, aminophylline, terbutaline and heliox. Patients requiring NIV and IMV were also excluded from analysis of the outcome measures but were used as balancing measures for the whole pediatric critical asthma cohort. The pre-implementation period was between January 2016 and September 2017. PDSA 1 period occurred from October 2017 through February 2019. PDSA 2 period occurred between March 2019 and June 2020, PDSA 3 period between July 2020 and September 2021, and PDSA 4 period occurred between October 2021 and May 2022.