HFNC Initiation Flow Rate Study - A Single Center, Randomized Controlled, Feasibility Study

We propose an open label, non-blinded, single center randomized controlled feasibility study to find the optimal initial HFnC flow rate in children less than 12 months old with clinically diagnosed moderate to severe bronchiolitis. This feasibility study is projected to take 6 months over the Winter/Spring of 2020-2021. The study is consisted of 3 arms, comparing HFnC therapy at 1 L/kg/min, 1.5 L/kg/min, and 2 L/kg/min (20 L/min max). Moderate to severe bronchiolitis is defined by RDai of 6 or more.15 The primary outcome is treatment response to HFnC therapy defined by RDai/Respiratory assessment Change Score (RaCS) [GreaterThanorequalTo] 4 at 4 hours of therapy. Secondary outcome measures comprise of treatment failure requiring an escalation of care during the first 24 hours of HFnC therapy, duration of HFnC and simple nasal cannula therapy, duration of simple nasal cannula therapy, hospital and PiCu length of stay (LoS), time to treatment failure, and adverse events. Respiratory Distress assessment instrument (RDai) and Respiratory assessment Change Score (RaCS)16 a previous study has shown the best predictors of admission were Spo2 value of less than 94%, RDai score greater than 11, and respiratory rate of greater than 60.17 We will use a RDai score [GreaterThanorequalTo] 6 to identify moderate to severe bronchiolitis. This score, along with vital signs, will be recorded at the initial patient encounter, 60 min, 90 min, and 4 hour, 12 hr, 24 hr of therapy, and at time of intervention including weaning and escalation. RaCS will be used to assess the change from one point in time to another. To determine RaCS, the subsequent RDai score is subtracted from the previous score to obtain the change. For example, if the initial RDai score is 7 and the reassessment score is 3, the patient has a score of +4. Positive score is indicative of improvement, and negative score demonstrates deterioration. in addition, respiratory rate is another component of the change score. a decrease in respiratory rate of 10% was defined as 1 positive change unit and an increase of 10% was defined as 1 negative change unit. The overall RaCS is calculated as the sum of change scores. improvement is defined as RaCS [GreaterThanorequalTo] 4 positive units. no improvement was defined as RaCS [Less Than] 4 positive units.