Bubble CPAP delivers a blended, humidified gas source to the infant’s airway via short binasal prongs. Here’s a look at best practices for initiating this noninvasive, low-cost therapy.
By Alyx Arnett
For the thousands of newborns and preemies with respiratory distress syndrome (RDS), taking those first breaths is a monumental challenge. RDS, among the top causes of death in the US in the first month of life,1 forces many into the neonatal intensive care unit (NICU), where they receive some form of respiratory support.
Given the unique needs and physiologies of these fragile patients, ventilatory support in the NICU must be tailored to prevent lung injuries and conditions like bronchopulmonary dysplasia (BPD), which has been linked to issues like developmental delay and lung function abnormalities later in childhood.2
One of the most common and successful noninvasive methods of respiratory support for this patient population is bubble CPAP (bCPAP). This method delivers a blended, humidified gas source to the infant’s airway via short binasal prongs. As the gas exits the tube, it creates bubbles that provide small airway pressure oscillations, helping prevent derecruitment of alveoli and improve work of breathing.
bCPAP is an attractive option due to its low cost and simplicity, as well as its association with reduced risk of BPD compared to mechanical ventilation.3
Penn State Health Turns to Bubble CPAP
Those factors influenced Penn State Health Children’s Hospital to overhaul its Level IV NICU and implement bCPAP in January 2020. In addition to being drawn to the cost savings, the hospital looked to the method to improve its BPD rate, which, in 2019, was 32%, well above the Vermont Oxford Network national average of 20%.
Within 18 months of using bCPAP, the NICU’s BPD rate dropped to 23%, the lowest in over 20 years. Since then, those involved in the implementation have created abstracts, presented lectures at medical conferences, and are conducting studies to offer insights into best practices and to provide data that could better inform clinicians, said Jennifer Erkinger MS, RRT-NPS, AE-C, C-NPT, neonatal/pediatric clinical specialist, neonatal ECMO coordinator, and pediatric ECMO specialist in the department of respiratory care at Penn State Health/Penn State Hershey Children’s Hospital.
“A big point (in going to bCPAP) was the fact that we are trying to avoid intubation and trying to avoid invasive ventilation with our heart and soul,” said Erkinger. “So, if your 23-weeker comes out and they are spontaneously breathing, we don’t use invasive ventilation anymore. We put them directly on bubble CPAP to open their alveoli to build that functional residual capacity (FRC). The number-one thing we do if any baby needs any type of noninvasive support, it will go on bubble CPAP right in the delivery within minutes of life. It’s a very important step.”
In certain situations, invasive ventilation may be deemed necessary in lieu of bCPAP, said Erkinger. These include if the baby is completely apneic with no respiratory effort; if the baby is having increased work of breathing as indicated by nasal flaring, grunting, and/or retracting; if the baby is having increased frequency of apneic events with associated bradycardia and desaturations; and if the baby has a diagnosis that bCPAP would be contraindicated in, such as a congenital diaphragmatic hernia or choanal atresia.
Preventing Lung Injury
Before adopting bCPAP, Penn State Health Children’s Hospital utilized flow-driven CPAP, which required staff to remove the interfaces from the babies to weigh them. This process disrupted respiratory support, as the baby was temporarily taken off CPAP, causing the lungs to start to derecruit.
“When you come off the mask, when you come off the interface, you’re just literally derecruiting. And when you derecruit, it causes physical injury and inflammatory exacerbation or what we call a ventilator-induced lung injury, and it’s not good for babies,” said Erkinger. “Once that lung is derecruited, it can take up to 45 minutes to re-recruit that lung.”
In the meantime, medical staff may see increases in the fraction of inspired oxygen (FiO2), retractions, and overall work of breathing in their patients.
With the bCPAP system used by Penn State Health Children’s Hospital, the baby can be weighed while wearing the device, which has been pre-weighed—including the interface and headgear—eliminating the chance of derecruitment and lung injury. “I can guarantee you it’s one of the reasons that our babies have done well because that baby has to stay bubbling at all times,” said Erkinger.
To ensure effective monitoring, Penn State Health Children’s Hospital reorganized its NICU to position all babies receiving respiratory support at the door, allowing medical staff to easily observe whether a baby is always bubbling. If bubbling stops, derecruitment begins immediately. The placement allows for timely interventions.
Medical staff also change patients’ interfaces regularly, effectively eliminating the risk of any infection, said Erkinger. Masks and prongs are changed ever four hours with a respiratory therapist (RT) and a registered nurse (RN) or two RNs to limit the chance of dropping the patient’s FRC. Headgear is changed every three days.
According to Beth Keifer and David Thompson, directors at Respiralogics, early recruitment of lung volume and augmenting spontaneous ventilation are keys to preventing lung injury in very low birth weight (VLBW) infants, and noninvasive application of bCPAP via bar-style nasal prongs in spontaneously breathing infants is the proven standard of care. “No other single noninvasive respiratory intervention has contributed more to the successful care of VLBW infants, the dramatic reduction of chronic lung disease, and device-related nasal trauma common in early ventilation and CPAP therapies,” said Keifer.
Weaning Babies from Bubble CPAP
A common question posed to Erkinger is how physicians determine the optimal timing for weaning patients from CPAP, given the lack of consensus. To address this issue, the hospital developed a set of guidelines after introducing bCPAP. The guidelines are designed to assist clinicians in making informed decisions regarding the weaning process, taking into account the unique needs of each patient.
Three criteria guide the process: Infants must be 32 weeks postmenstrual age, weigh a minimum of 1,600 grams, and have an FiO2 of 0.21. Weaning is initiated by reducing the water by one centimeter every week until a goal of five centimeters of water is achieved, after which the water is reduced to four centimeters for 24 hours before transitioning the infant to room air.
“That’s a foreign concept for a lot of NICUs. They want to go to high flow, or they want to go to nasal cannula. They’re not used to going straight from bubble CPAP to room air,” said Erkinger. “But we’ve been using bubble CPAP, and we’re extremely successful at this.”
The guidelines note that if a baby starts experiencing increased work of breathing, persistent apnea, and persistent desaturations when weaning that they should be moved to nasal cannula.
David Hendrickson, MBA, US infant care manager at Fisher and Paykel, said developing a uniform process—with room for flexibility—is key to success with bCPAP. “The success is in getting a consistent approach. The failure also is being too rigid in that approach. So at least from the onset of a baby’s life and recruiting a lung, everybody can usually get on the same page. It’s about how and when to get that baby off the therapy that it tends to get cloudy and get muddy, and then you’d lose the value of being consistent together.”
A More Challenging—and Effective—Therapy?
One of the challenges with bCPAP, said Hendrickson and Erkinger, is that it’s inherently harder to manage, requiring more training and attention to detail than other respiratory therapies.
“It’s a lot of work,” said Erkinger. “If you do it on a ventilator, you just shove a set of prongs in, and you turn the vent on. With flow driven, you just turn it on and walk away. Bubble CPAP takes much more dedication to ensure that you’re bubbling. This takes a lot more effort to ensure you’re giving consistent pressures, and maybe that’s one of the negative aspects about it, that your nursing teams, your RT teams have to be a lot more attentive to it. But we’ve done it, and you get used to it.”
Fisher and Paykel developed a neonatal lung model called Baby LIV (lung inflation visualizer) as a training tool to help medical staff visualize the differences between CPAP and nasal high-flow therapies and show how the choice of interface can impact therapy outcomes. The tool also helps address questions regarding pressure maintenance.
“It’s really a great tool to show nurses why your RTs are using this therapy and why your neonatologists want to put these kids on this therapy, even though it’s harder to manage,” said Hendrickson. “And once they understand that it’s protecting the baby, they will be the biggest fan and the biggest supporter of the therapy. And I think it’s been monumental from a training standpoint.”
Despite potentially requiring more effort upfront, the results are proving to be superior to those achieved with high-flow nasal cannula. A team at Penn State Health Children’s Hospital is currently conducting the first live study on babies that compares the pressures generated via bCPAP and the pressures generated during high-flow nasal cannula. Six of 30 babies have been enrolled, and Erkinger said initial data shows that bCPAP is the only interface that consistently generates the pressure that is set.
She expects the study to be published by the end of the year and said it could lead to more NICUs adopting the therapy.
“I think that’s what physicians and NICUs need is they need more evidence to prove it does reduce BPD and that its long-term effects are better than the flow-driven CPAP or the high-flow nasal cannula,” she said.
RT
Alyx Arnett is associate editor of RT. For more information, contact [email protected].
References
- Dyer J. Neonatal Respiratory Distress Syndrome: Tackling A Worldwide Problem. P T. 2019 Jan;44(1):12-14. PMID: 30675087; PMCID: PMC6336202.
- Landry JS, Chan T, Lands L, et al. Long-term Impact of Bronchopulmonary Dysplasia on Pulmonary Function. Can Respir J. 2011 Sep-Oct;18(5):265-70. doi: 10.1155/2011/547948. PMID: 21969927; PMCID: PMC3267603.
- Miller TA, Li J, Riddell S, Barkley SC. Decreasing Chronic Lung Disease Associated with Bubble CPAP Technology: Experience at Five Years. Pediatr Qual Saf. 2020 Apr 10;5(2):e281. doi: 10.1097/pq9.0000000000000281. PMID: 32426643; PMCID: PMC7190251.
