Feasibility and Blinding Validation of a Sham Bilevel Positive Airway Pressure System in Pediatric Acute Asthma

OBJECTIVE: To develop a sham bilevel positive airway pressure (sBPAP) circuit to attenuate airway pressures, preserve blinding among clinicians and patients while assessing short term safety and feasibility. We hypothesize sBPAP will successfully attenuate pressures, preserve blinding, and be safe and feasible in the clinical setting. METHODS: For this feasibility and blinding validation study, a single-limb BPAP circuit used an endotracheal tube (ETT), concealed in semi-opaque tubing, as a pressure restrictor. A Fluke VT900A Gas Flow Analyzer measure downstream pressures. The sBPAP was then used in a double-blind, randomized control trial where treating physicians and study patients reported if they believed active or sBPAP had been used. Exact Binomial testing was used to determine if blinding significantly differed from random chance. RESULTS: At set inspiratory positive and expiratory positive airway pressures of 10 and 5 centimeters of water, pressures were attenuated to 0.6 and 0.3, respectively. The ETT was not obviously visible and pressures displayed on the ventilator were similar to set pressures. Thirty-two pediatric patients were randomized and received sBPAP in a RCT with a mean age of 9.9 years (SD 3.8), 17 (53%) females, and mean Pediatric Respiratory Assessment Measure of 5.5 (SD 2.1). Twenty-one out of 37 respondents (57%, p = 0.51) correctly identified treatment assignment. There were no significant differences in adverse event rates between active and sBPAP. CONCLUSIONS: The described sBPAP demonstrated feasibility in that it successfully attenuated pressures, preserved blinding, and was not associated with an increased rate of adverse events in the clinical setting.