Measurement of Leak Volume as a Diagnostic Predictor of Post-extubation Stridor in Pediatric Patients

Abstract

Background: Endotracheal intubation can cause post-extubation stridor (PES). PES can prolong the hospital stay length and is linked to high mortality and morbidity, especially, if re-intubation is essential. Leak volume (LV) test is a simple method to detect upper airway edema. Objective: We aimed to evaluate the effectiveness of percent leak volume (PLV) and LV in predicting PES. Methods: Before extubation, expired tidal volume (VTe) and inspired tidal volume (VTi) were observed for 6 respiratory cycles during positive pressure ventilation. The average of the 6 VTi and 6 VTe values were recorded. LV was the difference between average VTi and average VTe. The conversion of the ratio of LV to average VTi into percentage was defined as PLV. Both LV and PLV were assessed to indicate cut-off values in predicting PES. Results: Among 77 patients, 39 patients (50.6%) developed PES. Both LV and PLV showed a significant decrease in patients with PES. ROC analysis indicated that LV at cut-off value < 18.34 ml gave a sensitivity of 82.1% and specificity of 57.9%, whereas PLV < 13.83% yielded 79.5% sensitivity and 57.9% specificity, for PES prediction. PLV and LV showed an area under the ROC curve of 0.770 (p < .001, 95%CI: 0.665, 0.874) and 0.706 (p = .01, 95%CI: 0.59, 0.821) respectively. Conclusion: LV and PLV could be used as a predictor of PES in pediatric patients.