To the Editor:
We previously described a method for selecting double-lumen tube (DLT) size based on the preoperative chest radiograph . We recently managed a patient in whom this technique would have been inappropriate.
A 36-yr-old, 5 prime 4 double prime 160-lb woman presented for right upper lobectomy for chronic atelectasis. She had undergone heart and bilateral lung transplantation 18 mo previously for primary pulmonary hypertension. Tracheal width, measured from the preoperative chest radiograph, was 19 mm. Her left bronchus was clearly visible on the radiograph and measured 10 mm. Her chest computed tomography scan confirmed both these measurements. A 39-French Broncho-Cath DLT (Mallinckrodt, St. Louis, MO) was placed without problems on the first attempt. The DLT functioned properly during the operation. There were no postoperative complications.
A postmortem study found a significant correlation between tracheal and bronchial dimensions in individual patients; the ratio of the diameter of the left bronchus to the trachea is 0.68 . Since the left bronchus often cannot be directly measured from the chest radiograph , we use tracheal diameter to predict left bronchial size and select a large DLT based on these values .
We prefer large DLTs since they cannot be advanced as deeply into the airway, have less resistance to airflow during one-lung ventilation, and require less air to inflate the bronchial cuff. Our patient's native trachea measured 19 mm, predicted left bronchial width was >12 mm, and a 41-French DLT would normally have been used. However, her lungs had been transplanted to the last distal ring of her native trachea, and the transplanted left bronchus was smaller (10 mm) than predicted. Therefore, a 39-French DLT was chosen.
We have used tracheal size to select DLTs for more than 300 patients without a single failure. This case illustrates an important exception-the patient after lung transplant whose transplanted bronchus may be significantly smaller than predicted from measurement of the native trachea.
Ali Habibi, MD
Sean Mackey, MD, PhD
Jay B. Brodsky, MD
Department of Anesthesiology; Stanford University School of Medicine; Stanford, CA 94305
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