To determine if servo-controlled oxygen environment is associated with reduction in (a) bradycardia events, (b) hypoxemic time, (c) bradycardia time, (d) apneic episodes

This study will enroll the subset of infants enrolled in the main study (PreVENT Aim 1; 401-1000g at birth and/or 22w 0d-28w 6d; enrolled at <1 week postnatal age; eligible for full care and surviving beyond 24 hours, with informed consent; and with no major malformations) who are receiving oxygen supplementation at 32w and 36w postmenstrual age (PMA), and are not judged too unstable by the Attending neonatologist.

For infants on oxygen supplementation at 32w PMA, the investigators will use data from the 96 hours of intensive multiparametric physiologic monitoring at 32w PMA. For infants on oxygen supplementation at 36w PMA, we will use the 96 hours of intensive multiparametric physiologic monitoring at 36w PMA as well as data from the sleep study.

The first 24 hours of data collection will be the baseline data. Over the next 72 hours, the investigators will evaluate 3 interventions in a cross-over manner with the initial intervention (cannula or oxygen environment) randomly assigned: Intervention 1 (24-48h of data), Intervention 2 (48-72h of data) and Intervention 3 (72-96h of data).

Inclusion Criteria:

- Inborn infants weighing 401-1,000 grams on admission and/or 22w 0/7d to 28w 6/7d (<29 weeks) inclusive completed weeks of gestation

Infants eligible for full care and resuscitation as necessary, and surviving beyond 24 h of age

Enrollment in main study protocol (Aim 1 of PreVENT Apnea) at <1 week post-natal age

This study will enroll the subset of infants from Aim 1 who are receiving oxygen supplementation at 32w and 36w PMA, and are not judged too unstable by the Attending neonatologist

Informed consent from parent/guardian

Exclusion Criteria:

- Refusal or withdrawal of consent Major congenital malformations (e.g., not including patent ductus arteriosus, small hernia)