Hypoxemic and hyperoxemic likelihood in pulse oximetry ranges: NICU observational study.

OBJECTIVE

Describe the likelihood of hypoxemia and hyperoxemia across ranges of oxygen saturation (SpO), during mechanical ventilation with supplemental oxygenation.

DESIGN

Retrospective observational study.

SETTING

University affiliated tertiary care neonatal intensive care unit.

PATIENTS

Two groups of neonates based on postmenstrual age (PMA): <32 weeks (n=104) and >36 weeks (n=709).

MAIN MEASURES

Hypoxemia was defined as a PaO <40 mm Hg, hyperoxemia as a PaO of >99 mm Hg and normoxemia as a PaO of 50-80 mm Hg. Twenty-five per cent was defined as marked likelihood of hypoxemia or hyperoxemia.

RESULTS

From these infants, 18 034 SpO-PaO pairs were evaluated of which 10% were preterm. The PMA (median and IQR) of the two groups were: 28 weeks (27-30) and 40 weeks (38-41). With SpO levels between 90% and 95%, the likelihoods of hypoxemia and hyperoxemia were low and balanced. With increasing levels of SpO, the likelihood of hyperoxemia increased. It became marked in the preterm group when SpO was 99%-100% (95% CI 29% to 41%) and in the term group with SpO levels of 96%-98% (95% CI 29% to 32%). The likelihood of hypoxemia increased as SpO decreased. It became marked in both with SpO levels of 80%-85% (95% CI 20% to 31%, 24% to 28%, respectively).

CONCLUSIONS

The likelihood of a PaO <40 mm Hg is marked with SpO below 86%. The likelihood of a PaO >99 mm Hg is marked in term infants with SpO above 95% and above 98% in preterm infants. SpO levels between 90% and 95% are appropriate targets for term and preterm infants.