Accuracy of stridor-based diagnosis of post-intubation subglottic stenosis in pediatric patients

Cláudia Schweiger, Larissa Valency Eneas, Denise Manica, Cátia de Souza Saleh Netto, Paulo Roberto Antonacci Carvalho, Jefferson Pedro Piva, Gabriel Kuhl, Paulo José Cauduro Marostica

To assess the accuracy of stridor in comparison to endoscopic examination for diagnosis of pediatric post-intubation subglottic stenosis. Children who required endotracheal intubation for >24h were included in this prospective cohort study. Children were monitored daily and underwent flexible fiberoptic laryngoscopy after extubation. Those with moderate-to-severe abnormalities underwent another examination 7-10 days later. If lesions persisted or symptoms developed, laryngoscopy under general anesthesia was performed. Patients were assessed daily for stridor after extubation. A total of 187 children were included. The incidence of post-extubation stridor was 44.38%. Stridor had a sensitivity of 77.78% (95% confidence interval [95% CI]: 51.9-92.6) and specificity of 59.18% (95% CI: 51.3-66.6) in detecting subglottic stenosis. The positive predictive value was 16.87% (95% CI: 9.8-27.1), and the negative predictive value was 96.15% (95% CI: 89.9-98.8). Stridor persisting longer than 72h or starting more than 72h post-extubation had a sensitivity of 66.67% (95% CI: 41.2-85.6), specificity of 89.1% (95% CI: 83.1-93.2), positive predictive value of 40.0% (95% CI: 23.2-59.3), and negative predictive value of 96.07% (95% CI: 91.3-98.4). The area under the receiver operating characteristic (ROC) curve was 0.78 (95% CI: 0.65-0.91). Absence of stridor was appropriate to rule out post-intubation subglottic stenosis. The specificity of this criterion improved when stridor persisted longer than 72h or started more than 72h post-extubation. Thus, endoscopy under general anesthesia can be used to confirm subglottic stenosis only in patients who develop or persist with stridor for more than 72h following extubation.