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

Abstract

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.

Use of the RAM Cannula with Early Bubble Continuous Positive Airway Pressure Requires Higher Pressures: Clinical and In vitro Evaluations

“…Previous work by this group and others have shown that bCPAP provided via the RAM cannula dampens the potentially beneficial pressure fluctuations of bCPAP and decreases the pressure measured at the cannula prongs by $35% from the set pressure. 7,14,16,17 Similar decreases in pressure transmission have also been seen with the use of the RAM cannula for noninvasive mechanical ventilation. 18,19 If the RAM cannula is employed in the DR for CPAP and in the early management of respiratory distress syndrome (RDS), increased set pressures may be required to provide adequate intra-alveolar pressures to maintain adequate FRC and avoid early endotracheal intubation.…”

“…Since the pressure fluctuations of bCPAP may play a role in gas exchange, the attenuation of these fluctuations by the RAM cannula could also affect our success. 4,5,7 During the 6-year period, we used either the FDA-approved bCPAP bottles from Babi.Plus or from B&B Bubbler, and these bottles may generate less pressure variations than the homemade version used at New York-Presbyterian or other available systems. 3 The infants in the DR did not have devices to close mouth, thus the CPAP levels could have been variable based on leak at mouth.…”

“…Our previous small randomized trial occurred during the time period (2014-2016) and per protocol the bCPAP pressures were increased prior to intubation for CPAP failure. 7 We analyzed the CPAP pressures based on calendar year due to trends within our unit to use increasing pressures with the RAM cannula. The majority of infants born less than 1,250 g in our NICU use the preemie RAM cannula, but this was not recorded in the delivery or NICU admission notes for all years.…”

“…4,6 The RAM cannula has demonstrated decreased transmission of pressure oscillation. 7 Early bCPAP is a strategy increasingly employed in the delivery room (DR) to avoid endotracheal intubation and mechanical ventilation. 8,9 Avoidance of invasive ventilation decreases the barotrauma and atelectotrauma seen in lungs subjected to positive pressure ventilation.…”

“…We hypothesized that increasing the set pressure of bCPAP delivered via the RAM cannula would decrease the incidence of DR intubation and early CPAP failure within 72 hours of delivery. To further evaluate the increased CPAP pressures observed and to expand on our previous in vitro work, 7 we used a simulated pharyngeal model to examine the effect of different CPAP interfaces (RAM cannula, Babi.Plus SBP, and Fisher & Paykel SBP), nasal occlusion percentages, RAM cannula sizes, and airflow on the transmitted pressures.…”