P1.090: Amylase Levels in Chest Tube Output: A Biomarker for Early Detection of Esophageal Leaks in Children

Background: Anastomotic leaks (AL) following esophageal anastomoses in children are common, and early identification is key to reducing morbidity. The use of chest tubes to detect AL varies, and it is unclear if chest tube output, quantity or composition can signal AL before clinical symptoms arise. Amylase levels in chest tube drainage may serve as a biomarker for early AL detection. We investigate the diagnostic accuracy of amylase levels in chest tube drainage as a biomarker for early detection of esophageal AL in children.

Methods: This single-institution retrospective cohort study included children who underwent esophageal anastomoses between March 2023 and August 2024. ALs were classified as contained or uncontained, and as clinically significant or minimally symptomatic. Daily amylase levels were measured from chest tube output while the tubes remained in place. The relationship between amylase levels and AL presence was analyzed.

Results: Sixty-eight children (median age 6 months [IQR 2-24.5], median weight 6.9 kg [4.1-11]) were included. One child (1.5%) had a clinically significant, uncontained AL requiring reoperation, and three (4.4%) had contained, minimally symptomatic leaks treated with antibiotics. Chest tubes remained for a median of 7 days (range 5-9). Amylase levels were significantly elevated in the child with a clinically significant leak (1776 U/L) compared to contained leaks (mean 20 U/L, range 9-26 U/L) and no leaks (mean 38.28 U/L, range 3-335 U/L), p< 0.001. No correlation was found between output volume or postoperative day and amylase levels. Amylase >1000 U/L had 100% sensitivity (95% CI 0.025–1) and specificity (95% CI 0.946–1) for detecting clinically significant AL, but sensitivity dropped to 25% (95% CI 0.006–0.806) with 100% specificity (95% CI 0.944–1) for all ALs (including contained). Amylase elevation preceded clinical symptoms by one day in the child with the significant leak. Similar elevations (>1000 U/L) were observed in cases of esophageal perforation due to other etiologies, including ischemia following esophageal mobilization and post-dilation injury.

Conclusion: Elevated amylase levels in chest tube output are a highly sensitive and specific marker for clinically significant esophageal AL in children, providing early detection before clinical symptoms. Postoperative amylase monitoring can streamline care by identifying patients at low risk for leaks, enabling earlier chest tube removal, potentially avoiding esophagograms, and facilitating earlier oral feeding.