Predictors of severe respiratory distress syndrome in preterm neonates below 34 weeks gestational age

1. Introduction Respiratory distress syndrome is the leading cause of respiratory morbidity and mortality in preterm neonates less than 34 weeks. The primary cause is surfactant deficiency due to immaturity of the pulmonary alveolar epithelium. Advances in neonatal care such as surfactant administration, non invasive ventilation, early rescue surfactant therapy, and less invasive surfactant administration have significantly improved survival and outcomes. Surfactant therapy is usually administered when positive end expiratory pressure is more than 6 cm H2O and fraction of inspired oxygen is more than 30 to 40 percent. Previous predictive studies were retrospective, based on data from outside India, and therefore limited in generalizability. Biomarker based studies exist but are resource intensive and not widely feasible. There is a lack of prospective studies from India that assess clinical predictors of severe respiratory distress syndrome requiring surfactant.
2. Aim To assess the ability of antenatal, intrapartum, and postnatal clinical details to predict the severity of respiratory distress syndrome in preterm neonates between 24 weeks and 33 weeks 6 days of gestational age.
3. Objectives To identify maternal and neonatal factors associated with severe respiratory distress syndrome in preterm neonates less than 34 weeks. To compare risk factors in neonates with severe respiratory distress syndrome and those with mild or no respiratory distress syndrome. To study comorbidities associated with respiratory distress syndrome in preterm neonates.
4. Justification for the Study There is limited data on the predictive ability of antenatal, intrapartum, and postnatal factors in the era of routine antenatal steroid use. A reliable prediction model can enable better decision making by obstetricians and neonatologists, improve parental counselling regarding neonatal outcomes, and optimize timely interventions such as early surfactant administration.
5. Methodology This is a prospective observational study. The study will be conducted in the Neonatal Intensive Care Unit of Kasturba Hospital, Manipal. All preterm neonates born at less than 34 weeks of gestation during the study period and admitted to the neonatal unit as per inclusion criteria will be considered for inclusion.

Maternal data will include antenatal history, use of steroids, and mode of delivery. Neonatal data will include gestational age, birth weight, sex, Apgar scores, perinatal history, need for respiratory support, and comorbidities such as sepsis, bronchopulmonary dysplasia, intraventricular haemorrhage, retinopathy of prematurity, and mortality. Severity of respiratory distress will be assessed using the Silverman Anderson Score, and oxygen saturation will be measured using pulse oximetry.

Gestational age will be assessed from the last menstrual period and confirmed by ultrasound. If there is a discrepancy, ultrasound dating will be preferred. Postnatal assessment will also be done using New Ballard Scoring. Written informed consent will be obtained from parents on day one of life.

6. Study Groups Group one Severe respiratory distress requiring surfactant therapy, defined as neonates with respiratory distress needing CPAP or PEEP more than 6 cm H2O and FiO2 more than 30 percent to maintain oxygen saturation between 90 and 95 percent.

Group two Neonates not requiring surfactant therapy, including those with no respiratory distress or with mild respiratory distress not requiring surfactant.

7. Statistical Analysis Categorical variables will be analysed using the chi square test. Continuous variables will be analysed using the t test. A p value less than 0.05 will be considered significant. Predictive ability of maternal and neonatal factors will be assessed using a generalized linear model. Data will be entered in Excel and analysed using SPSS software.
8. Outcome Measures The primary outcome will be the requirement of surfactant therapy in preterm neonates less than 34 weeks. The secondary outcomes will be comorbidities such as sepsis, bronchopulmonary dysplasia, intraventricular haemorrhage, retinopathy of prematurity, and mortality.
9. Ethical Considerations No additional tests will be performed. Neonates will continue to receive care as per standard NICU protocols. Confidentiality will be ensured, and only deidentified patient data will be used for analysis. The risk is minimal and limited to data confidentiality. There are no direct benefits to participants, but the findings may indirectly benefit preterm neonates through improved clinical decision making and counselling.
10. Review of Literature Respiratory distress syndrome is a common and serious complication in preterm neonates less than 34 weeks. Surfactant deficiency leads to significant respiratory morbidity and mortality. Advances such as surfactant therapy, non invasive ventilation, early rescue surfactant therapy, and less invasive surfactant administration have improved neonatal outcomes. The criteria for surfactant therapy generally include positive end expiratory pressure more than 6 cm H2O and fraction of inspired oxygen more than 30 to 40 percent. Previous predictive studies were retrospective and non Indian, limiting their applicability. Biomarker based studies require additional resources and are not always feasible. There is a need for a prospective study in the Indian setting to assess maternal and neonatal clinical predictors of severe respiratory distress syndrome requiring surfactant therapy.