Preterm infants born before 28 weeks gestation are at risk for lung disease and require oxygen and pressure to keep their lungs open. This usually involves a device called nasal continuous positive airway pressure (nCPAP). When preterm babies reach a certain age, they are ready to begin to feed by mouth, but for those on nCPAP, oral feeds are usually not started due to concerns for choking. This may cause them to miss their window of learning and may lead to a longer hospital stay or oral aversion. Sometimes babies are switched from nCPAP to low flow oxygen (LFO2) for a short time for oral feeds, but this may not provide enough support for their lungs. Heated, humidified high flow nasal cannula (HHHFNC) is another mode of providing oxygen and pressure. It is equal to nCPAP in small babies transitioning off of ventilators, but no studies have been done in older babies. We plan to compare the feeding of babies orally using either nCPAP with LFO2 or HHHFNC in preterm babies born before 28 weeks gestation who are now 34 weeks corrected gestational age. The goal will be the fastest time to full oral feeds.

The primary objective of this study is to assess whether a baby born at less than 28 weeks gestation who at 34 weeks corrected gestational age, will reach full oral feeds faster on the current practice of nasal continuous positive airway pressure (nCPAP) and low flow oxygen (LFO2) or the new intervention of heated, humidified high flow nasal cannula (HHHFNC).

The specific aim of this study is to investigate the effectiveness and safety of using nCPAP and LFO2 versus HHHFNC for reaching full oral feeds in premature infants.

We hypothesize that the use of HHHFNC at the initiation of oral feeding will allow babies to reach full feeds sooner as compared with nCPAP and LFO2.

Babies born at extreme prematurity (<28 weeks gestation), are at risk of chronic lung disease due to lung immaturity. A proportion of preterm infants remains dependent on non-invasive ventilation at the corrected gestational age when they are at the neurodevelopmental stage of oral feeds. If oral feeds are not initiated in a timely manner, delays in progression of oral feeds and oral aversion may occur, resulting in longer hospital stays and/or gastrostomy tube insertions. Those that are nCPAP dependant are unable to orally feed due to safety concerns so are placed on a low pressure system of low flow nasal cannula during feeds. This may lead to microatelectasis in those babies needing a higher pressure to maintain gas exchange. HHHFNC is another method of non-invasive ventilation and it can be changed from a high pressure system (in litres per minute) to a low pressure system by turning a dial, and not having to disconnect the baby from the respiratory system.

Randomized controlled trial consisting of two arms: 1) The CPAP/LFO2 arm in which the babies will be maintained on nCPAP until the time of oral feeds wherein they will have their circuits exchanged for a low flow cannula. 2) The HHHFNC arm in which babies will be maintained on 5 lpm of HHHFNC until the time of oral feeds, wherein they will have their flows turned down to 2 lpm. The study will be conducted in a level III neonatal intensive care unit (NICU) in Mount Sinai hospital. The study subjects are 40 preterm babies that were born before 28 weeks gestational age who are now 34 weeks corrected gestational age (CGA), which are dependent on non-invasive ventilation and are receiving full feeds via nasogastric tube. The randomization will occur at 33+6/7 weeks CGA. Demographic characteristics will be compared between groups using Chi-square test or Fisher's exact test for categorical variables. Differences between continuous variables will be assessed using Student's t-test or Mann-Whitney U test for non-normally distributed variables. The primary outcome (time to full oral feeds) is a binary outcome and will be compared between groups using Chi-square test or Fisher's exact test. A difference of a p-value of <0.05 will be considered significant.

Inclusion Criteria:

• Gestational age of <28 weeks (24+0 to 27+6) with corrected gestational age of 34 weeks
• Neonates requiring respiratory support in the form of nCPAP or HHHFNC at any pressure at 34 weeks corrected gestational age and failing a trial of low flow oxygen or room air
• Full enteral feeding tolerated through a nasogastric tube

Exclusion Criteria:

• Gestational age > 28 weeks
• Neonate requiring biphasic nCPAP
• Mother never at the bedside and no consent for bottle feeds
• Severe nasal breakdown or genetic/neurologic abnormalities which impair oral feeding