138 - Development of a Clinical Definition for Respiratory Distress Syndrome Associated with Preterm Mortality in the Ethiopian Neonatal Network

Poster Number: 138
Publication Number: 138.111

Danielle Ehret, The University of Vermont Children's Hospital, Burlington, VT, United States; Erika M. Edwards, Robert Larner, M.D., College of Medicine at the University of Vermont, Burlington, VT, United States; mahlet Abayn, St Paul's Hospital Millennium Medical College, Addis Ababa, Adis Abeba, Ethiopia; Asrat D. Gebremedhin, Tikur Anbessa Specialized Hospital, Addis Ababa, Adis Abeba, Ethiopia; Yohanes M. Hailu, University of Gondar, Gondar, Amara, Ethiopia; Gesit metaferia, St.paul's Hospital Millennium Medical College, Addis Ababa, Adis Abeba, Ethiopia; Lucy T. Greenberg, Vermont Oxford Network, Burlington, VT, United States; Kate Morrow, Vermont Oxford Network, Burlington, VT, United States; Bogale Worku, Ethiopian pediatrics society, addis ababa, Adis Abeba, Ethiopia; Jeffrey D. Horbar, Larner College of Medicine University of Vermont, Burlington, VT, United States

Background: Respiratory Distress Syndrome (RDS) is the leading cause of mortality of preterm infants in low- and middle-income countries (LMIC), yet a standardized clinical definition that excludes radiography and blood gas criteria, which are less available in low-resourced settings, or models to guide judicious use of constrained therapeutic resources including continuous positive airway pressure (CPAP), the first-line and maximum therapy for RDS in many LMIC settings, do not exist. The extent to which an objective clinical assessment, the modified Downes’ score (MDS) is associated with respiratory failure is unknown.

Objective: To develop a clinical definition of RDS applicable to low-resourced settings and to compare treatment thresholds to maximize net benefit

Design/Methods: We studied 1016 infants < 37 weeks’ gestation admitted to 4 Ethiopian Neonatal Network member hospitals from June 2019 to June 2020 with presumed RDS, defined as respiratory distress present on admission and treated with oxygen, CPAP or mechanical ventilation within 24 hours. We used logistic regression to determine the association of components of the MDS with the outcome of death due to respiratory failure. We compared a “treat all” strategy to strategies based on clinical definition, predictive model for severe RDS and predictive model for death due to respiratory failure in a decision curve analysis.

Results: The mortality rate of infants with presumed RDS was 44.7%, which varied by severity of disease (Table 1). Abnormalities in respiratory rate (mild adjusted risk ratio (aRR) 1.33, 95% CI 1.12, 1.58; severe aRR 1.75, 95% CI 1.41, 2.17) retractions (mild aRR 1.9, 95% CI 1.32, 2.73; severe aRR 2.87, 95% CI 2.21, 3.72) and air entry (mildly decreased aRR 3.26, 95% CI 1.72, 6.18; markedly decreased aRR 4.06, 95% CI 2.27, 7.26) as components of the MDS were associated with death due to respiratory failure (Table 2). Between the threshold probabilities of 2 to 20% of severe RDS, the highest net benefit derived from a predictive model guiding receipt of therapy (Figure 1).Conclusion(s): Preterm infants with presumed RDS have a high mortality rate, with multiple components of the MDS associated with death due to respiratory failure. We propose a clinical definition of RDS: central cyanosis in room air or supplemental oxygen requirement within the first 24 hours plus moderate respiratory distress on clinical exam as assessed by the MDS of 4 or greater. Models incorporating maximum MDS, birth weight and receipt of antenatal steroids may help guide judicious distribution of current and future RDS therapies for infants at risk of severe RDS.
Table 1. Patient DemographicsInfants’ presumed RDS severity categorized by treatment received. Mild RDS: received oxygen cannula; Moderate RDS: received CPAP with pressure 6cmH20 or less without escalation; Severe RDS: received CPAP with pressure > 6cmH20, mechanical ventilation, or died due to respiratory failure.
Table 2. Association of Modified Downes’ Score Components with Death due to Respiratory FailureModel adjusted for birth weight, inborn status and exposure to antenatal steroids.
Note: Modified Downes’ Score may be calculated while patient receiving supplemental oxygen therapy.