Changes in Pulmonary Function After A Caffeine Loading Dose and Extubation Outcome in Preterm Infants with Respiratory Distress Syndrome

Abstract

Abstract BACKGROUND: Prolonged endotracheal intubation in preterm infants leads to adverse outcomes including bronchopulmonary dysplasia, pneumonia and sepsis. Extubating preterm infants early can lead to apneas, respiratory distress and hypoxemia with reintubation, a destabilizing and traumatic event. Identifying readiness for extubation would avoid these harmful events. Current clinical criteria perform poorly in predicting extu-bation outcome in preterm infants. Caffeine is used to facilitate extubation and also affects pulmonary function. OBJECTIVES: To determine pulmonary functions before and after a caffeine loading dose in preterm infants < 31 weeks gestation with respiratory distress syndrome (RDS) undergoing their first trial of extubation and use them to predict extubation outcome. DESIGN/METHODS: We determined dynamic compliance (Cdyn), tidal volume (TV), minute ventilation (MV), and dynamic airway resistance (Rdyn) before and after a loading dose of 10 mg/kg of caffeine base in preterm infants <31 weeks gestation with RDS prior to extubation. These measurements were taken as an average of ten non-distorted breaths with < 10% endotracheal air leak. Infants were ventilated with the EvitaXl Neo (Draeger, Germany). Pulmonary function readings were downloaded from the ventilator. Extubation failure was defined as the need for reintubation within 72 h after extubation. Exclusion criteria included grade 3-4 intra-ventricular hemorrhage, sedation, pneumothorax, medications affecting pulmonary function, chromosomal and congenital malformations. Mann Whitney test was used for continuous variables and the χ2 or Fisher’s exact test for dichotomous data. A p value <0.05 was considered significant. RESULTS: Blood gas values and ventilator parameters were similar between the groups before extubation.There was significant improvement in pulmonary function after a loading dose caffeine. Amongst pulmonary functions, ratio of Cdyn before and after caffeine performed best in predicting extubation outcome with an area under the curve of 0.85 (95% CI 0.79-0.94). CONCLUSION: Caffeine improves pulmonary function in preterm infants. A ratio of dynamic compliance before and after caffeine best predicted extu-bation outcome. Our results need validation in a prospective study.