Supplementary Material for: Comparison of Bubble CPAP Devices Using RAM Cannula for Extubation Failure in Very Low Birth Weight Infants: Randomized and Cohort Studies

Introduction: Bubble continuous positive airway pressure (bCPAP) generates a variable pressure due to bubble size and frequency, and these pressure oscillations may contribute to lung recruitment and gas exchange. Single-outlet bCPAP devices generate larger pressure fluctuation than bCPAP devices with diffusers, but clinical efficacy is unclear. Our hypothesis was that a single-outlet bCPAP device (B&B Bubbler©) would decrease extubation failure and improve oxygenation compared with a bCPAP device with a diffuser (BabiPlus©). Methods: Bench testing of bCPAP devices with the RAM© cannula determined pressure averages, fluctuations, and CPAP transmission at prongs. The B&B Bubbler© and the BabiPlus© devices were compared for oxygenation and bCPAP failure within 72 h of extubation in a randomized trial in infants less than 1,250 g (n = 43). Additionally, a cohort study with infants extubated to BabiPlus© (n = 128), B&B Bubbler© (n = 119), and noninvasive positive pressure ventilation (NIPPV) (n = 107) were compared. Results: Small differences in pressure fluctuations between bCPAP devices are attenuated by the RAM© cannula. Pressures at RAM© prongs are 62% of set pressure. The bCPAP extubation failure rate (35%) and oxygenation were similar between the bCPAP devices. bCPAP success was associated with lower FiO2 at extubation and decreased need for additional FiO2 in both groups. In the setting of the RAM© cannula, there were no differences in extubation failure rate for infants extubated to bCPAP or NIPPV. Conclusions: There were no clinical differences at extubation between the B&B Bubbler© and BabiPlus© devices. Oxygenation may predict bCPAP failure. The use of the RAM© cannula as a bCPAP interface should be more closely examined.