Oxygenation Index & Oxygen Saturation Index
The oxygenation index (OI) combines FiO₂, mean airway pressure, and PaO₂ into a single number that grades the severity of hypoxemic respiratory failure. The oxygen saturation index (OSI) substitutes the non-invasive SpO₂ for PaO₂ (OI ≈ 2 × OSI). Toggle between them below — both help track disease severity and inform inhaled nitric oxide and ECMO decisions in term and late-preterm infants.
OI = (FiO₂% × mean airway pressure cmH₂O) ÷ PaO₂ mmHg. OSI = (FiO₂% × mean airway pressure) ÷ SpO₂%; OI ≈ 2 × OSI.
Muniraman HK, et al. Evaluation of oxygen saturation index compared with oxygenation index in neonates with hypoxemic respiratory failure. JAMA Netw Open. 2019;2(3):e191179. doi:10.1001/jamanetworkopen.2019.1179
Thresholds for iNO and ECMO vary by center and gestational age and are not firmly established in preterm infants. Interpret alongside the clinical picture, pre/post-ductal saturations, and echocardiography. Educational tool — not a substitute for clinical judgment.
Frequently asked questions
How is the oxygenation index calculated?
OI = (FiO₂% × mean airway pressure in cmH₂O) ÷ PaO₂ in mmHg. The OSI substitutes SpO₂ for PaO₂, with OI ≈ 2 × OSI.
What OI is used for iNO or ECMO?
Thresholds vary by centre and gestational age. In term/late-preterm infants, inhaled nitric oxide is often considered around OI 15–25 and ECMO around OI ≥40.
Be the first to react