Tracheoesophageal fistulae (TEF) are difficult to detect and require a high index of suspicion. We hypothesized that capnography to identify a spike in end-tidal carbon dioxide (etCO2) during esophagoscopy with carbon dioxide (CO2) insufflation would facilitate TEF diagnosis because of gas passage from the esophagus to the trachea.
Medical records of 42 consecutive cases of recurrent, acquired, or missed congenital TEF diagnosed between January 2015 and November 2019 that underwent esophagoscopy with CO2 insufflation were reviewed. A control cohort of 97 similarly endoscopically evaluated patients with surgical confirmation of absence of recurrent TEF (eg, patients undergoing posterior tracheopexy) was also collected. All patients underwent pre-operative esophagoscopy, bronchoscopy, and capnography; diagnostic abilities of various combinations of modalities for TEF identification were calculated.
Statistical analysis identified a maximum intra-esophagoscopy end-tidal CO2 level of 68 mmHg as the optimal discriminator between cases and controls, though in practice, we anecdotally find that recurrent TEFs typically permit rapid rise ≥90 mmHg. Increasing numbers of diagnostic modalities increased diagnostic sensitivity to detect recurrent TEF; the highest diagnostic sensitivity for TEF identification was achieved by the combination of intra-esophagoscopy fluoroscopy with bronchoscopy and capnography ≥68 mmHg (sensitivity = 88.1%). There were multiple cases of TEF (N = 7 for etCO2 ≥68 mmHg, N = 3 for etCO2 ≥90 mmHg) identified by capnography that were missed by esophagoscopy. There were 5 (for etCO2 ≥68 mmHg) or 6 (for etCO2 ≥90 mmHg) cases of recurrent TEF that were missed by all nonsurgical methods.
Attention to etCO2 during esophagoscopy with CO2 insufflation represents a simple, novel way to detect TEF. Identification of TEF remains challenging, though combinations of diagnostic modalities improve diagnostic sensitivity.