Transpyloric Versus Gastric Feeding in Bronchopulmonary Dysplasia

Oxygen saturation will be measured by continuous pulse oximetry throughout the 2 week trial. The proportion of time per day with an oxygen saturation (SpO2) less than 80% will be calculated and reported as a median value observed over the 2 week trial.

A serious adverse event (SAE) will be defined as any adverse experience that is at least possibly related to the study intervention and results in any of the following outcomes:

• death,
• a life-threatening event (at risk of death at the time of the event),
• prolongation of existing hospitalization beyond what would be expected for a preterm infant who requires extended respiratory support near and beyond term corrected gestation, or
• a persistent or significant disability/incapacity.

The total number of GER episodes during a 24 hour period will be measured using 24 hour esophageal pH-multichannel intraluminal impedance (pH-MII) monitoring. Testing is performed by inserting a pH-MII catheter into the esophagus via the nasal or oral route. Reflux episodes are recorded during a 24 hour monitoring period and the total number is tabulated. 24 hour pH-MII testing will be performed prior to randomization and on day 14 (last day) of the clinical trial.

The number of GER episodes detected by 24 hour esophageal pH-MII monitoring that reach the proximal sensor will be recorded and divided by the total number of recorded impedance episodes (regardless of esophageal height)

The total number of reflux episodes with a pH<4 will be recorded during 24 hour pH-MII monitoring

Saliva and tracheal samples will be collected by gentle suctioning and analyzed for concentration of pepsin, a biomarker of GER. Quantification will be performed using commercially available assay.

Saliva and tracheal samples will be collected by gentle suctioning and analyzed for concentration of bile acids, a biomarker of gastro-duodeno reflux. Quantification will be performed using commercially available assay.

Occurrence of hypoxemic episodes will be recorded using continuous pulse oximetry. Intermittent episodes will be defined as oxygen saturation (SpO2) values <80% lasting longer than 10 seconds.

Occurrence of hypoxemic episodes will be recorded using continuous pulse oximetry. Prolonged episodes will be defined as oxygen saturation (SpO2) values <80% lasting longer than 60 seconds.

Aspiration events will be diagnosed as will define aspiration as a witnessed regurgitation (milk in the mouth, clothing respiratory equipment, etc.) event with subsequent clinical decompensation (increase in inspired oxygen by an absolute difference of 20% or more or an increase in delivered mean airway pressure by at least 5cm H2O for ≥ 24 hours beginning within 24 hours of the observed regurgitation event.

Respiratory severity score is calculated as the delivered mean airway pressure multiplied by supplemental oxygen level. Values will be computed as the daily time weighted average.

The FLACC scale assesses pain by observing five categories of behaviors and assigning a score of 0-2 to each category, resulting in a total score of 0-10:

Face: Facial expressions, such as a smile, grimace, or frown Legs: Leg movement, such as kicking, drawing legs up, or remaining relaxed Activity: Movement, such as lying quietly, squirming, or remaining tense Cry: Crying, moaning, whimpering, or complaining Consolability: Response to comfort, such as being reassured by touching or hugging, or being difficult to console

FLACC scores will be assessed during routine nursing care (at least twice daily) and summarized as median daily values

Total dose of narcotic medications received during the 2 week trial will be tabulated in morphine and midazolam equivalents and summarized as mg/kg exposure.

Number of times the feeding tube is replaced due to dysfunction or inadvertent dislodgment.