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

摘要

Objective Describe the likelihood of hypoxemia and hyperoxemia across ranges of oxygen saturation (SpO_2), 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_2 < 40mm Hg, hyperoxemia as a PaO_2 of >99mm Hg and normoxemia as a PaO_2 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_2-PaO_2 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_2 levels between 90% and 95%,the likelihoods of hypoxemia and hyperoxemia were low and balanced. With increasing levels of SpO_2, the likelihood of hyperoxemia increased. It became marked in the preterm group when SpO_2 was 99%-100% (95% Cl 29% to 41 %) and in the term group with SpO_2 levels of 96%-98% (95% Cl 29% to 32%). The likelihood of hypoxemia increased as SpO_2 decreased. It became marked in both with SpO_2 levels of 80%-85% (95% Cl 20% to 31 %, 24% to 28%, respectively). Conclusions The likelihood of a PaO_2 <40 mm Hg is marked with SpO_2 below 86%. The likelihood of a PaO_2 >99mm Hg is marked in term infants with SpO_2 above 95% and above 98% in preterm infants. SpO_2 levels between 90% and 95% are appropriate targets for term and preterm infants.