Introduction
Bronchopulmonary dysplasia (BPD) is the most common comorbidity associated with very preterm birth; 10,000-15,000 infants annually have this condition 1,2. Infants with BPD are at increased risk for health complications after Neonatal Intensive Care Unit (NICU) discharge 3. During the first year of life they are at increased risk of being readmitted to the hospital, and frequently receive home oxygen therapy and additional medications such as inhaled and systemic corticosteroids 4-8. For this reason, strategies to optimize safe NICU discharge for infants with BPD are an important focus of research.
A previous study found that infants discharged from the NICU with a pre-discharge blood gas partial pressure of carbon dioxide (pCO2) >60 mmHg had a higher risk of post-discharge adverse outcomes including hospital readmission 3. Baseline hypercapnia may indicate reduced respiratory reserve, which may place infants at risk for post-discharge complications 3,9. For infants discharged with home oxygen therapy, who already have increased healthcare needs after discharge, the potential readmission risk associated with baseline hypercapnia may indicate an infant who is not ready for NICU discharge. Due to this, it is our hospital’s recommendation to discharge infants with BPD with home oxygen therapy only after they have a pCO2 ≤ 60 mmHg on capillary blood gas. However, there have been no prospective studies examining outcomes following the use of pre-discharge pCO2 as a clinical guideline.
The objective of this study was to determine whether, for infants with BPD discharged with home oxygen therapy, capillary blood gas pCO2 obtained prior to NICU discharge was correlated with increased respiratory readmissions or other pulmonary healthcare utilization in the year after NICU discharge. We hypothesized that higher pCO2 in these infants would be a surrogate marker for increased pulmonary fragility after NICU discharge, and therefore would be associated with more readmissions and other hospital encounters, more outpatient respiratory medical management and longer duration of home oxygen therapy.