Abstract Introduction Elevated respiratory end-tidal CO2 (EtCO2) during esophagoscopy insufflation is commonly used to detect bronchial-esophageal fistulas (BEF). CO2 insufflation can result in blood absorption and real-time monitoring of blood CO2 in patients with suspected BEF may improve monitoring for complications and potentially patient safety. Description A 17-year-old patient suffered a right thorax gunshot wound resulting in scapular fracture with transmediastinal transit through the esophagus and bilateral lungs. Thoracotomy was performed for bilateral penetrating lung injury and esophageal repair at the level of the first rib. No tracheal injury was noted on initial bronchoscopy or chest imaging. A protracted hospital course was complicated by development of pneumomediastinum, mediastinal abscess, and elevated pleural fluid amylase from esophageal leak with extravasation of contrast on esophagoscopy requiring partial closure with endoclips and endoscopic vacuum sponge. Subsequent bronchoscopy and simultaneous esophagoscopy (HD73) demonstrated a large esophageal defect with contiguous abscess cavity. EtCO2 rose rapidly with esophagoscopy CO2 insufflation (99 mmHg) and serial bronchoscopic balloon occlusion isolated the BEF to the right upper lobe segments (RB1-3). Transcutaneous CO2 (tcCO2) monitoring showed increased CO2 as high as mid-70’s mmHg from baseline in the 40’s, corresponding with CO2 insufflation that spontaneously resolved after 30 seconds of continued mechanical ventilation. The patient was transferred to an outside hospital for esophagectomy and right upper lobectomy with eventual discharge home. Discussion Causes of BEFs include malignancy, congenital anatomic anomalies, iatrogenic or traumatic injury, prolonged mechanical ventilation, foreign bodies and infections. Rapid diagnosis and treatment are necessary to prevent complications of respiratory failure, sepsis, and death. Esophagoscopy with barium extravasation is commonly used to detect esophageal injury, however aspiration of contrast into the lungs can complicate use with BEFs. EtCO2 spikes ≥68 mmHg during esophagoscopy CO2 insufflation is another detection method, though sensitivity may be diminished with small fistulas. Serial bronchoscopy-guided balloon occlusion has been used to isolate bronchopleural fistulas and less commonly for temporary isolation of BEFs. A retrospective case series suggests all three techniques has the highest diagnostic sensitivity. TcCO2 monitoring provides a non-invasive and accurate surrogate of PaCO2 and supports diffusion of CO2 into the blood stream with insufflation. Our case highlights the rapid increase of tcCO2 in the presence of a BEF, as well as the rapid normalization of transcutaneous CO2 during mechanical ventilation. We postulate that patients with underlying lung disease may be at higher risk for unanticipated intraprocedural hypercapnia and acidosis with potential for clinical complications. This abstract is funded by: None
Dwyer et al. (Fri,) studied this question.