Using a home oxygen weaning protocol and pCO2 to evaluate outcomes for infants with bronchopulmonary dysplasia discharged on home oxygen

Abstract

Background: Predischarge capillary blood gas partial pressure of carbon dioxide (pCO₂ ) has been associated with increased adverse events including readmission. This study aimed to determine if predischarge pCO₂ or 36-week pCO₂ was associated with increased respiratory readmissions or other pulmonary healthcare utilization in the year after neonatal intensive care unit (NICU) discharge for infants with bronchopulmonary dysplasia (BPD) discharged with home oxygen, using a standardized outpatient oxygen weaning protocol.

Methods: This was a secondary cohort analysis of infants born <32 weeks gestational age with BPD, referred to our clinic for home oxygen therapy from either from our level IV NICU or local level III NICUs between 2015 and 2017. Infants with major nonrespiratory comorbidities were excluded. Subject information was obtained from electronic health records.

Results: Of 125 infants, 120 had complete 1-year follow-up. Twenty-three percent of infants experienced a respiratory readmission after NICU discharge. There was no significant association between predischarge or 36-week pCO₂ and respiratory readmissions, emergency room visits, new or increased bronchodilators, or diuretics. Higher 36-week pCO₂ was associated with a later corrected age when oxygen was discontinued (<6 months; median, 54 mmHg; interquartile range [IQR], 51-61; 6-11 months; median, 62 mmHg; IQR, 57-65; ≥12 months, median, 66 mmHg; IQR, 58-73; p = .006).

Conclusions: Neither predischarge pCO₂ nor 36-week pCO₂ was associated with 1-year respiratory readmissions. However higher pCO₂ at 36 weeks was associated with a longer duration of home oxygen. Neonatal illness measures like 36-week pCO₂ may be useful in communicating expectations for home oxygen therapy to families.

Keywords: bronchopulmonary dysplasia; home oxygen therapy; pCO2.

FIGURE 1

Algorithm for weaning home oxygen. The NICU and referral groups were seen in BPD clinic 4–6 weeks following NICU discharge. At the first visit the infants were placed on room air and observed for 15–30 min. If they fail, then they are followed up in 2–3 months and the room air trail is repeated. If they pass, then room air trials at home are started and they are followed up ever 4–6 weeks until oxygen is discontinued. The parents gradually extend the homeroom air trials with a goal of 12 h during the day. Once the infant is tolerating 12 h on room air during the day, the parents call pulmonary and a home overnight pulse oximetry study is performed on room air. Oxygen is discontinued when the infant has passed the home overnight pulse oximetry study. If they fail the home oximetry study, then it is repeated in 4–6 weeks. BPD, bronchopulmonary dysplasia; NICU, neonatal intensive care unit

FIGURE 2

pCO₂ and corrected age at discontinuation of home oxygen. This graph shows how pCO₂ was associated with the age at discontinuation of oxygen. The y axis shows pCO₂ and the x axis shows corrected age at discontinuing oxygen. The box shows the median predischarge pCO₂; circles show median 36-week pCO₂.Vertical bars indicate interquartile range. p values indicate nonparametric Kruskal-Wallis tests between groups

FIGURE 3

Duration of home oxygen. This figure shows a survival curve of the timing of discontinuation of home oxygen in our cohort. The y axis shows the proportion of infants discontinuing home oxygen; the x axis shows the number of weeks after neonatal intensive care unit discharge on home oxygen