Clinical Utility of Oxygen Saturation Index Compared with Oxygenation Index in Neonatal Respiratory Diseases: A Prospective Observational Study

Introduction: The neonatal period is one of the most critical phases in an individual’s life. During this time, newborns undergo significant physiological changes as they adapt from the intrauterine to the extrauterine environment. Respiratory diseases in neonates are associated with an increased risk of mortality, morbidity, and adverse neurological outcomes. Hence, monitoring neonates using oxygenation indices is essential. Aim: To determine the correlation between the Oxygen Saturation Index (OSI) and the Oxygenation Index (OI) among term and preterm neonates mechanically ventilated for respiratory diseases. Materials and Methods: A prospective observational study was conducted among 80 neonates with primary respiratory diseases requiring mechanical ventilation, admitted to a tertiary care hospital in North Karnataka, India. Newborns with cardiac diseases were excluded. All neonates were monitored using a pulse oximeter for OSI and Arterial Blood Gas (ABG) analysis for OI. Pearson’s correlation analysis and Receiver Operating Characteristic (ROC) curve analysis (p-value <0.05) were used to assess the relationship between OI and OSI. Results: Out of 80 neonates, 59 (73.75%) were inborn and 21 (26.25%) were outborn, 52 (65%) neonates were preterm and 28 (35%) were term, with a male-to-female ratio of 7:3. Of 80 neonates, 48 (60%) newborns were diagnosed with Respiratory Distress Syndrome (RDS), 21 (26.25%) with Meconium Aspiration Syndrome (MAS), and 11 (13.75%) with pneumonia. About 35 (43.8%) neonates had a gestational age between 28 and 33 weeks, with RDS being the most prevalent disease in this group. The most common cause of respiratory disease among term neonates was MAS. Out of 80 neonates, 44 (55%) survived and 36 (45%) expired. OI showed a moderate positive correlation with OSI (r-value=0.444, p-value=0.01). The Area Under the Curve (AUC) value for OSI in predicting mortality was higher compared to that for OI, and both were found to be statistically significant (p-value=0.001). Conclusion: OSI, being non invasive, can be used as an alternative to OI for monitoring oxygenation in ventilated neonates with respiratory diseases. It is also cost-effective and reduces the risk of sepsis and phlebotomy-induced anaemia.