Plasma Levels Of SRAGE Do Not Predict Postextubation Distress After A Successful Weaning Trial

Abstract

RATIONALE: Postextubation distress after a successful spontaneous breathing trial is associated with increased morbidity and mortality. The soluble form of the receptor for advanced glycation end-products (sRAGE) is a marker of alveolar type I epithelial cell injury, and levels of sRAGE are elevated during acute lung injury. It remains unknown whether sRAGE levels can be useful in identifying patients at risk for postextubation distress during the process of weaning from mechanical ventilation. OBJECTIVES: To verify whether plasma sRAGE levels can be predictive of postextubation distress or weaning failure. METHODS: 89 patients from 2 intensive care units were included in this observational prospective study. Plasma sRAGE levels were measured in duplicate by ELISA before and at the end of a 60-minutes spontaneous breathing trial (SBT), and 4 hours after extubation. To quantify lung aeration, a lung ultrasound score was calculated. MAIN RESULTS: Patients who succeeded SBT (86%) and those who failed (14%) had no differences in sRAGE levels, before (median 954 pg/mL and 1021 pg/mL, respectively, p=0.8) and at the end of SBT (median 876 pg/mL and 1038 pg/mL, respectively, p=0.7). 27 patients (35% of extubated patients) experienced postextubation distress. Patients with or without postextubation distress had comparable sRAGE levels before SBT (median 1131 pg/mL and 872 pg/mL, respectively, p=0.4), after SBT (median 1106 pg/mL and 839 pg/mL, respectively, p=0.7), and 4 hours after extubation (1075pg/mL and 1027 pg/mL, respectively, p=0.3). In patients with postextubation distress, sRAGE levels were not predictive of the need for non invasive or invasive ventilation. sRAGE levels were not associated with lung aeration whether time points were considered separately (before, after SBT, 4 hours after extubation) or together (Spearman's rho=0.05; p=0.5). CONCLUSIONS: Plasma levels of sRAGE do not predict SBT failure/success or postextubation distress in patients undergoing a weaning trial. Lung aeration loss during a successful weaning trial may predict postextubation distress, but cannot be evaluated by sRAGE levels in this setting. sRAGE is a marker of alveolar epithelial injury in the acute setting of ALI/ARDS but does not seem useful in the weaning period.