Hypercapnia and Its Association With Long-term Respiratory Morbidities in Premature Infants With Chronic Lung Disease

Data collection will begin once an infant no longer requires mechanical ventilation, CPAP, and HFNC, up to twice per week while in the NICU. Investigators will obtain up to twenty minutes of end-tidal capnography data, using Masimo ISA modules with continuous CO2 display. Five minutes of good quality data, at approximately 30 breaths per minutes, should provide approximately 150 data points. After filtering for artifact, the mean and range of end tidal CO2 will be recorded during this interval. These recordings will be started after a feed for infants receiving enteral feeds. The capnography cannula will be placed by the bedside nurse or respiratory therapist at the conclusion of a feed and removed no later than the next feed. If data is unable to be obtained, investigators will attempt to collect it at the next regularly scheduled interval. Available blood gases with pCO2 will also be recorded during the NICU hospitalization. After discharge, consented subjects who are followed in the BCH outpatient pulmonary clinic will have capnography recorded at every clinic visit for a period of up to twenty minutes, and mean and range of end-tidal CO2 will be recorded after filtering for artifact. Available blood gases with pCO2 during pulmonary visits will be recorded; blood gases during sick encounters (i.e. emergency room) will be excluded. From available electronic medical record (EMR) and clinic note data, investigators will also record duration of time on respiratory support including positive pressure ventilation and nasal cannula oxygen.