Respiratory Severity Score and Its Association with Adverse Outcomes in Extremely Low Birth Weight Infants Undergoing Invasive Mechanical Ventilation

Abstract

Background: Respiratory severity score (RSS) is a simple, non-invasive respiratory failure assessment tool that its appropriateness for lung disease severity is well-established. Objectives: This study aimed to investigate the potential value of early-life RSS values in predicting mortality or severe bronchopulmonary dysplasia (BPD) in infants with extremely low birth weight (ELBW) undergoing invasive mechanical ventilation. Methods: Following a retrospective approach, the current multi-center study intended to estimate the RSS and RSS/kg values in the first three days of life and time-weighted means of these values in ELBW babies who received invasive mechanical ventilation. Participants were categorized into two groups of survival without severe BPD and those with severe BPD or death. All RSS values and other risk factors were compared between groups. A multivariate logistic regression analysis was used to identify factors affecting severe BPD or death. The sensitivity and specificity of RSS values in predicting severe BPD or death were estimated using receiver operating characteristic (ROC) curves. Results: A total of 101 infants met the inclusion criteria. All RSS and RSS/kg values in the first three days of life were found to be significantly higher in the severe BPD or death group. The maximum area under the curve (AUC) in the ROC curves created for the respiratory severity score values was determined as RSS/kg mean with a cut-off value of 3.62 (85.3%), (P = 0.001). According to the multivariate logistic regression analysis, which included risk factors that may affect the development of severe BPD or mortality, both the mean RSS/kg score and the duration of invasive mechanical ventilation maintained statistically significant. [RSS/kg mean; OR = 2.28 (1.37 – 3.78), P = 0.001], [invasive MV duration; OR = 1.08 (95% CI, 1.03 – 1.14), P = 0.003]. Conclusions: This study demonstrated that high RSS/kg mean values in the early periods of life are valuable in predicting severe BPD or death in ELBW babies undergoing invasive mechanical ventilation. Furthermore, mean RSS had more predictive power than single RSS determinations, and incorporating body weight was associated with improved sensitivity of the score.