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Individual QI Projects from Single Institutions

Decreasing Chronic Lung Disease Associated with Bubble CPAP Technology: Experience at Five Years

Miller, Tricia A. PhD*; Li, Jing MA; Riddell, Stella CNS, RN; Barkley, Steven C. MD

Author Information
doi: 10.1097/pq9.0000000000000281
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Chronic lung disease (CLD) continues to be an important cause of long-term morbidity, and a contributing cause of prolonged hospitalization and risk for ventilator-associated pneumonia.1–3 Current literature identifies multiple risks and complications associated with mechanical ventilation, including frequent failure to tolerate early extubation.4,5 Reasons for extubation failure include: upper airway instability, poor respiratory drive, chest wall compliance, alveolar atelectasis, anemia, and ventilation lung damage.6–8

Noninvasive ventilation (NIV), with the early application of nasal continuous positive airway pressure (CPAP), decreases the rate of CLD when compared with institutions where NIV has not been commonly instituted.4,9 CPAP can be delivered using two types of CPAP generators—variable flow and continuous flow systems. Bubble CPAP (bCPAP) has been reported as a safe and cost-effective method for delivering CPAP, both as primary therapy, and as support for the newly extubated preterm infant.10–12bCPAP utilizes blended gas that is heated and humidified and then delivered through a low-resistance nasal prong. The distal end of the expiratory tubing is submerged underwater; the depth of submersion determines the CPAP pressure generated.13,14

bCPAP was first shown to reduce the need for supplemental oxygen at 28 days of life in an observational study conducted by Avery et al.15 Because of that landmark study, the guidelines for the use of bCPAP have evolved, including recommendations for its use with low birth weight infants.16 More recently, empirical studies have shown that the functional nature of bCPAP decreases the work of breathing, the incidence of intubation, and the need for medication.17,18 Some randomized trials have compared ventilator–derived nasal CPAP with bCPAP in treatment of respiratory distress in preterm neonates19–22; however, in an observational study conducted by Khashu et al23 comparisons were made between 2 groups of less than 32-week babies: those who used ventilator-derived CPAP and those that used bCPAP. Results showed a significant reduction in the use of exogenous surfactant, postnatal steroids, and the duration of mechanical ventilation with the use of bCPAP.

Recent literature indicates the use of CPAP over mechanical ventilation decreases the frequency of analgesic or sedative medication use in very low birth weight infants.24–27 The purpose of this report is to review our implementation of a system of bCPAP and to evaluate its impact on CLD and sedative medication use in a community hospital NICU.


Setting and Patient Sample

This report included 156 infants born in Cottage Children’s Medical Center’s (CCMC) Neonatal Intensive Care Unit in Santa Barbara, Calif., from November 2006 to October 2016. CCMC’s NICU is a 22-bed Level III facility. Infants were included in the study if they received bCPAP, conventional ventilation, or both; and if they were discharged to home or foster care. This project did not require Institutional Review Board approval because it was determined to be quality improvement in nature.

Before November 1, 2011, some exploration of NIV using CPAP had been undertaken, but with limited success, either in avoiding ventilation or in increasing postextubation success. Thus, the initiation of the bCPAP project was carefully timed and prepared. After the development of policies and procedures, identification of clinical champions, and training of the nursing and respiratory staff, we introduced bCPAP on November 1, 2011. Initially we used bCPAP to support larger infants, over 90 days, the gestational age of inclusion was gradually reduced to include all suitable patients.


This quality improvement initiative was led by a multidisciplinary team of neonatologists, neonatal nurses, and respiratory therapists who traveled to Columbia Presbyterian’s NICU to study the elements of the successful implementation and maintenance of bCPAP therapy. The core team developed a protocol based on best practice recommendations from Levesque et al.11 Based on these recommendations, all NICU staff were trained by the core team in guidelines and the technical aspects of bCPAP.

Implementation of the bCPAP guidelines began on November 1, 2011. Training of the staff consisted of small-group sessions with hands-on practice. The core team observed staff initiate and maintain infants on bCPAP while staff learned the nuances of the technique. To ensure compliance with the guidelines, the team used a checklist (Table 1). The team was asked to complete the checklist every 2 hours. During the implementation, the core team maintained high visibility and empowered staff to accomplish changes while offering support and assistance for problem-solving during the transition. The core team members followed up on problems and provided opportunities for staff to clarify issues. The clinical nurse specialist led the team through the quality improvement process and ensured standardization of care. Table 2 outlines a timeline with process-specific details for the implementation of bCPAP.

Table 1.
Table 1.:
bCPAP Checklist
Table 2.
Table 2.:
Timeline for bCPAP Implementation


Our goal was to evaluate the impact of this practice change on CLD and the use of sedative drugs over a prolonged period. CLD was defined using Vermont Oxford Network Definition 1—the need for supplemental oxygen at 36 weeks postmenstrual age. We collected data on sedative drug use for each patient for the duration of their hospital stay, and comparisons were made between patients who received care during the bCPAP period (November 1, 2011 to October 31, 2016) to the previous 5-year cohort where bCPAP was not used.

The following clinical outcomes were also measured and compared between the bCPAP and conventional ventilation only groups in this study: gender, gestational age, delivery type (C-section or vaginal), admission weight, length of hospital stay, Respiratory Distress Syndrome, number of days of mechanical ventilation, number of days on oxygen, Pneumothorax, Patent Ductus Arteriosus (PDA), PDA Surgically-repaired (PDAS), Necrotizing Enterocolitis, Intraventricular Hemorrhage (Grades I to IV), Severe Intraventricular Hemorrhage (Grades III or IV), Intraventricular Hemorrhage Requiring Ventriculo-Peritoneal Shunt (IVHS), and Retinopathy of Prematurity (Grades II or above).

Data Collection and Statistical Analysis

We assessed the effectiveness of bCPAP by retrospective examination and review of charts of patients who received respiratory support that was either by bCPAP or conventional ventilation only. Data were gathered starting 5 years before implementation (November 1, 2006 to October 31, 2011) and 5 years postimplementation of the bCPAP protocol (November 1, 2011 to October 31, 2016). The primary mode of noninvasive ventilation support in the preimplementation period was a high-flow nasal cannula. Data on sedation/analgesia (eg, Ativan, phenobarbital, morphine, or fentanyl) usage were collected and examined.

Statistical analysis was performed using the R Core Team.28 As this study is exploratory, missing values were treated as a category and were not imputed. For variables containing missing values, the total number of available data points is noted in the table. We defined the baseline covariates as gender, gestational age, delivery type, and admission weight. Gender and delivery type were both balanced, respectively, between the control and the intervention groups (P > 0.99), whereas gestational age (P = 0.009) and admission weight (P = 0.02) were not (Table 3). To account for heterogeneity between the baseline covariates of the control and the intervention groups, we conducted statistical matching using the MatchIt package in R.29 Specifically, the Matchit function was utilized, and gestational age and admission weight were included as the pretreatment covariates. The nearest neighbor matching method with the Mahalanobis distance with replacement was chosen when conducting the statistical matching.

Table 3.
Table 3.:
Patient Characteristics and Clinical Outcomes before Statistical Matching

Numerical variables were first examined by conducting a Shapiro–Wilk normality test. As none of the numerical data were normally distributed, we chose their median and interquartile range (IQR) as summary statistics. Discrete variables were summarized using absolute and relative frequencies. A 2-sided unpaired student’s t test or 2-sided Wilcoxon rank-sum test was used to test the significance of continuous variables, and a 2-sided chi-square test or 2-sided Fisher’s exact test was used to test the significance of discrete variables.


Before statistical matching, 156 neonates were eligible for this study; their baseline characteristics and outcomes are summarized and compared in Table 3. After matching gestational age and admission weight between the control and intervention groups, we retained 132 neonates in this study for analyses. We report the postimplementation of the bCPAP protocol results as follows.

There were no statistically significant differences in length of stay, the incidence of respiratory distress syndrome, and pneumothorax between the control and the intervention groups (Table 4). The median days on supplemental oxygen for the control group was 33 (IQR = 7.5–66) and 0 (IQR = 0–0) for the intervention group (P < 0.001). There was a median decrease from 18 (IQR = 5–42.5) to 0 (IQR = 0–7) days on a ventilator between the control group and the intervention group (P < 0.001). We observed a decrease in the incidence of chronic lung disease from 26 patients (30%) in the control group to 2 patients (4%) in the intervention group (P = 0.002). Although it did not reach statistical significance at α = 0.05, there was a median decrease from 76 (IQR = 52–104.5) to 66 (IQR = 48–84) days of length of stay between the control and the intervention groups (P = 0.09). PDA and PDAS results favored the intervention group (P = 0.009 and P = 0.008, respectively). We did not report results for IVHS in Tables 3 and 4 because patients in either group did not develop IVHS.

Table 4.
Table 4.:
Patient Characteristics and Clinical Outcomes after Statistical Matching

The use of sedatives was investigated and compared between the groups receiving bCPAP or only conventional ventilation. There were markedly more sedative doses in the conventional ventilation group compared to the bCPAP group (P < 0.001). Specifically, the average number of sedative doses was 5.20 (SD = 31.97) for the conventional ventilation group and 1.43 (SD = 9.98) for the bCPAP group.


We have demonstrated that the successful implementation of bCPAP results in lower incidences of CLD in preterm neonates at our institution. We also observed significant decreases in the use of sedative medications in the bCPAP group compared with the conventional ventilation only group. It has long been recognized that a significant portion of the long-term medical burden carried by premature infants is a consequence of therapy, rather than disease. For example, the variation in the risk of CLD among 8 different centers, as first reported by Avery et al,15 was striking, and recent reports have raised the concern that sedative medications may have a deleterious effect on the developing brain.30–33 Some research suggests negative long-term neurocognitive side effects with the use of sedative drugs in preterm neonates, particularly in very low birth weight infants.24 Other studies have reported no effect of sedative strategies on infants.31 For these reasons, developing systems of care that are less invasive and which can allow minimization of the use of potentially harmful medications is highly desirable. bCPAP, when properly administered and carefully monitored, is comfortable and well tolerated by the newborn with acute respiratory failure.

We believe that this is the reason that we have been able to decrease the use of sedative medications substantially compared with the previous period. To date, our findings are the first to show a decrease in sedative medication dosing using bCPAP in a community hospital NICU. These findings may influence standardization and process improvement for other hospitals with similar patient demographics.

Comparative outcome data across California NICUs for CLD (Vermont Oxford Network Definition 1) was prepared by the California Perinatal Quality Care Collaborative (CPQCC) for the specific 5-year intervals before and after the initiation of this bCPAP project. Figures 1,2A and B demonstrate remarkable improvement in the rate of CLD when compared with all other NICUs in California. Before the initiation of the bCPAP protocol in November 2011, we had attempted NIV in a poorly coordinated way but felt that it had promise. This result is reflected in the lowering CLD rate seen in 2010 (Fig. 1), but it was not until we instituted a system-wide change that we experienced such positive results.

Fig. 1.
Fig. 1.:
Changing incidence of CLD following implementation of bCPAP QI project. The circles represent rates of CLD at Cottage CCMC preimplementation and postimplementation of bCPAP from 2003 to 2017. The diamonds show the California Perinatal Quality Care Collaborative (CPQCC) network, the solid line indicates the 95% CI of the O/E CLD ratio. This graph is reprinted with permission from the CPQCC.
Fig. 2.
Fig. 2.:
A, Rates of CLD in CPQCC network NICUs preimplementation of bCPAP (November 1, 2006 to October 31, 2011). B, Rates of CLD in CPQCC network NICUs postimplementation of bCPAP (November 1, 2011 to October 31, 2016). CPQCC, California Perinatal Quality Care Collaborative.

The observation that the incidence of PDA was significantly decreased between the 2 time periods is of interest. Whether this is related to the change in respiratory support modality, or other changes in care, is not clear at this time.

Some limitations of this report include unanticipated difficulty with the use of the bCPAP machine, specifically, the placement of prongs and maintenance of securing devices on the neonates. Through collaborative discussion within the department and communication with clinical experts from Morgan Stanley Children’s Hospital, we undertook improvements in positioning, as well as changes in the frequency of refreshing the securing systems. Other barriers to change, such as time, equipment challenges, the financial cost (eg, staff training and education), and protocol logistics were overcome to demonstrate and sustain outcomes successfully. To maintain patient safety, we allocated an “introduction period” of 1 year to ensure that we could accomplish definitive practice change. Continued team engagement was crucial to sustain the culture change and a sense of program ownership.


We have shown that improved respiratory outcomes and decreased use of sedative drugs for preterm infants can be achieved by the implementation of a bCPAP protocol and using quality improvement methodologies. The essential elements of success for this quality improvement initiative were a collaborative team using standardized practices based on evidence, the implementation of checklists, the frequent reassessment of successes and problems, as well as the use of a core team of clinical experts as resources to the full staff. Physician, nurse, and therapist dedication to the project is essential. We are optimistic that the improved outcomes demonstrated by CCMC’s NICU team are encouraging for process improvement in other community hospital settings.


The authors have no financial interest to declare in relation to the content of this article.


We are grateful to CCMC’s NICU staff for their passion and commitment to providing the best care possible for infants and their families in our community. Our sincere appreciation to Barbara Donnelly, MD, Theresa Lueck, MD, Jennifer Ferrick RN, Kevin Johnson, RRT, and Shannon Nicoponski. We are grateful to Dr. Henry Lee for his thoughtful review and critique of the manuscript. Thank you to the CPQCC for their support and generation of time-specific reports. Finally, we are most grateful to the nursing and respiratory therapy staff of the NICU, which took this project to heart and made it part of our culture.


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