A Fluoroscopic Diagnosis of Bronchus Suis or Porcine Bronchus to Explain Hypoxemia During Anesthesia

Abstract

To the Editor: Migration of the endotracheal tube tip into the right main bronchus and hemoglobin oxygen desaturation is a possible complication in children undergoing cardiac catheterization procedures. In these patients, position changes (head flexion, raising arms above the shoulders) may occur. Therefore, the tracheal tube is taped at a higher level than usual to avoid this problem.1 We report a case where despite these precautions, there was an unusual cause for persistent hemoglobin oxygen desaturation in a young child. A child with abnormal pulmonary venous drainage into the superior vena cava presented for cardiac catheterization. Anesthesia was induced with sevoflurane followed by IV rocuronium for tracheal intubation. To avoid inadvertent right main intubation, which can occur when the patient’s arms are raised up for positioning in the Catheterization laboratory, the endotracheal tube tip was deliberately placed in a higher location in the trachea. Despite this precaution, hemoglobin oxygen desaturation occurred and the airway/ventilation were reevaluated. Fluoroscopy revealed that the tip of the endotracheal tube was in midtrachea 2 cm above the carina; however, the right upper lobe was not ventilated since the tube tip was below the opening of an abnormal right upper lobe (RUL) bronchus. The diagnosis of “Porcine Bronchus” or “Broncho Suis,” an infrequent congenital abnormality in which an aberrant right upper lobe bronchus arises from the mid or distal third trachea rather than from the right main bronchus, was made (Fig. 1). The clinical significance of this abnormality is the association of recurrent atelectasis of RUL, recurrent pneumonia, congenital strider, laryngomalacia, presence of tracheal stenosis, high incidence of genetic disorders (Down’s syndrome), and cardiopathies.2 This anomaly would not have been considered in the differential diagnosis of desaturation without immediate availability of fluoroscopic guidance. After diagnosis, the tip of the tracheal tube was maintained above the orifice of the abnormal bronchus with the use of intermittent fluoroscopic confirmation.Figure 1.: Right upper lobe bronchus arising from the middle at the trachea instead of the right main bronchus.Susan Verghese, MD Greg Jensen, MD Kanishka Ratnayaka, MD Joshua Kanter, MD Department of Anesthesiology and Children’s Heart Institute Children’s National Medical Center Washington, DC [email protected]