Effective Fraction of Inspired Oxygen With Nasal Cannula in Premature Infants

During routine nasal cannula (NC) use in the newborn ICU, the actual fraction of oxygen
inspired by the infant, i.e. the effective FiO2 (Effective-FiO2) that reaches the infant's
airways, cannot be easily determined. The effective FiO2 during NC use is generally lower
than the FiO2 in the gas delivered by NC at the infant's nose due to dilution with ambient
gas entrained by the infants during spontaneous inspiration. The factors influencing
effective FiO2 include the set FiO2 of the gas delivered by NC (NC-FiO2), the NC-flow rate,
and the entrainment of ambient gas by the infant during each spontaneous inspiration. The
individual contribution of each of these factors to the variability in effective-FiO2 in
extreme premature infants has not been systematically evaluated.

The objective of this study is to determine the multifactorial relationship between the
effective fraction of inspired oxygen (Effective-FiO2) and the FiO2 in the gas delivered by
the nasal cannula (NC-FiO2), NC flow rate, spontaneous minute ventilation and other patient
characteristics in premature infants who receive supplemental oxygen via nasal cannula (NC).

Inclusion Criteria:

- Premature infants born between 23 and 30 weeks of gestational age

- Receiving supplemental oxygen via nasal cannula

- Parental informed consent

Exclusion Criteria:

- Major congenital anomalies

- Clinically unstable