Following informed consent, will be stratified based on weight (<1250 grams and >1250 grams), as well as oxygen delivery requirement (NCPAP/mechanical ventilation) at time of enrollment. Randomization will occur as soon as possible following eligibility criteria being met. All enrolled infants will be randomized into one of two different sequences for evaluation of the short-term effect of gas flow rate on transcutaneous PCO2 (Aim 1). Enrolled infants will be randomly assigned by numbered opaque envelopes containing a card that indicates the assigned treatment order (block method using random number table by individuals not involved in care of the infants) (one of two group sequences). Then, infants who meet eligibility criteria as outlined above for Aim 2 will be randomized to either oxygen hood or ideal nasal cannula flow for a period of one week, by numbered opaque envelopes containing a card that indicates the assigned treatment group.