Respiratory severity score and extubation readiness in very low birth weight infants

Background: The respiratory severity score (RSS) is a byproduct of mean airway pressure (MAP) and fraction of inspired oxygen (FiO(2)). We sought to determine whether RSS could be used as a screening tool to predict extubation readiness in very low birth weight (VLBW) infants. Methods: In a retrospective cohort study, medical records of all VLBW infants admitted to our unit (6/1/09-2/28/12) were reviewed for infants' demographics, prenatal characteristics, and medication use. Also, records were reviewed for unplanned vs. planned extubation, blood gas, ventilator parameters and signs of severe respiratory failure [RF, defined as partial pressure of carbon dioxide (pCO(2)) > 65, pH < 7.20, FiO(2) > 50%, and MAP > 10 cm] on the day of extubation. Results: During the study period 31% (45/147) failed extubation. Overall, infants who failed extubation had a lower birth weight (BW) and gestational age (GA), and on the day of extubation had a higher RSS and percentage of having one or more signs of severe RF. In a logistic regression model, adjusting for BW, GA, RSS and RF, RSS remained the only risk factor associated with extubation failure [adjusted OR 1.63 (95% CI: 1.10-2.40); p = 0.01]. RSS had a sensitivity of 0.86 (95% CI: 0.72-0.94) at a cutoff of 1.26 and a specificity of 0.88 (95% CI: 0.80-0.94) at a cutoff of 2.5. There was no difference in extubation failure between unplanned vs. planned extubation [41% (9/22) vs. 29% (36/125); p = 0.25]. Conclusion: An elevated RSS is associated with extubation failure. Successful unplanned extubation is common in VLBW infants. Copyright (C) 2017, Taiwan Pediatric Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license.