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

Abstract

Objective Early bubble continuous positive airway pressure (bCPAP) in the delivery room (DR) reduces early intubation, mechanical ventilation, and bronchopulmonary dysplasia. The RAM cannula, adopted for ease of patient care, is a high resistance nasal interface that, when used with bCPAP, only transmits a portion of set pressures and attenuates the bubble effects. This study aimed to review early bCPAP pressures and bCPAP failure with the RAM cannula interface over a 6-year period. Study Design Retrospective, single-center study of infants delivered <1,250 g from 2013 to 2018 (n = 735) begun on bCPAP in the DR with the RAM cannula. In vitro testing of bCPAP pressure transmission was also performed for multiple nasal interfaces and nasal occlusion percentages. Results The percentage of infants intubated in the DR decreased over time (59 to 42%), while the average bCPAP pressure increased from 5.3 to 6.8 cmH2O. A total of 355 infants (48%) were admitted to the neonatal intensive care unit (NICU) from the DR on BCPAP. The failure rate for bCPAP in NICU within 72 hours decreased from 45 to 24% as the maximum CPAP increased from 5.8 to 7.6 cmH2O. Pneumothorax rates did not change. CPAP pressure transmission decreased with all sizes of the RAM cannula. Conclusion When utilizing the RAM cannula for bCPAP, higher CPAP levels were associated with decreases in DR intubations and CPAP failure within the first 72 hours. If clinicians choose to use the RAM cannula for bCPAP, they will need higher set pressures to achieve lung inflation and the beneficial oscillatory effect will be diminished. Key Points

Nasal Cannula with Long and Narrow Tubing for Non-Invasive Respiratory Support in Preterm Neonates: A Systematic Review and Meta-Analysis

“…Though CLNT possibly results in lower oropharyngeal pressure transmission when compared to SBP/NM (meta-analysis of non-RCTs), clinical benefit or harm could not be ruled out for most of the outcomes evaluated, highlighting the need for future trials on this question. Our finding of lower oropharyngeal pressure transmission with CLNT is consistent with the earlier in vivo and bench studies on CLNT showing lower pressure delivery with CLNT [ 4 , 15 , 16 , 17 , 19 , 20 , 21 , 36 ]. The RAM cannula is quite similar to the traditional nasal prongs used to provide supplemental oxygen.…”

“…The characteristics of the included studies are given in Table 1 . The reasons for the studies that were excluded are given in Supplement Table S3 [ 4 , 17 , 19 , 21 , 36 , 37 , 38 , 39 ]. The comparator in four of the six included studies was SBP [ 18 , 23 , 24 , 25 , 26 ].…”

Role of ventilator and nasal interface in pressure transmission during neonatal intermittent positive pressure ventilation: A bench study

“…5,6 The devices used to administer NIPPV include flow generators combined with jet systems and conventional mechanical ventilators in pressure control mode, while commonly used nasal interfaces are nasal masks, short bi-nasal prongs, and the RAM cannula. Two bench studies investigated the accuracy and stability of ventilatorgenerated NCPAP in the presence of leaks 7 and spontaneous breathing activity of the patient 8 ; while several studies compared different nasal interfaces during NCPAP [9][10][11][12][13][14] and NIPPV. [15][16][17] However, to our knowledge, no studies simultaneously evaluated different possible determinants of the pressure transmission to the lung during nasal IPPV.…”

Early Physiological and Adrenal Effects of Budesonide Mixed with Surfactant in Large Observational Preterm Cohort Study

“…Our practice did change to encourage delayed cord clamping. We also changed nasal interfaces for bubble CPAP in 2019 and increased initial pressures in the delivery room, so fewer infants may have required intubation [19, 30]. The CRIB II scores, Apgar scores, birth weights, and GAs would suggest that these are still similar cohorts.…”