Use of NIRS in Preterm Population Born at Altitude

Inclusion Criteria: * Infant must be \<32 weeks' gestational age at time of delivery. * Consenting mother/guardian of the infant must speak English. Other languages are not being included due to the need of a translator being brought into the unit, which adds risk to the vulnerable population. Additionally, as the time to consent is a narrow window, adding the complexity of getting a translator may delay the ability to get consent and thus make it more difficult to enroll patients. * Infants that require blood transfusions during the monitoring time may be included. Exclusion Criteria: * Any known cardiac anomaly or other anomaly which may impair perfusion and blood flow. * Infant born after placental abruption or concern for extreme blood loss immediately after birth. * Unable to consent the mother/guardian due to maternal health issues after delivering (eg requiring intubation or sedation after the delivery). * Mothers/guardians that are prisoners, as the study team would like to have continuing communication with the mother during the study period as needed. * Mothers/guardians that are \<18 years of age will not be approached for consent. * Any mother/guardian that is not able to consent due to having a legal representative will not be approached for consent in this study. * Any infant that is planned to be placed for adoption * Infant is greater than 24 hours of age at time of consent.