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.