Predicting the size of a double-lumen endobronchial tube using computed tomographic scan measurements of the left main bronchus diameter

We investigated the use of chest computer tomographic (CT) scan measurement of the left mainstem bronchial diameter to predict the correct left-sided double-lumen endobronchial tube (DLT) size in Asian patients who may requir e smaller DLT sizes. Fifty consecutive Asian adults aged 17-80 yr with preo perative chest CT scans undergoing elective thoracic surgery were entered i nto the study. The measurements of the left main bronchus diameter were mad e by using the electronic calipers of the spiral scanner to the nearest mil limeter. The sizes of DLT selected were 32F, 35F, 37F, 39F, and 41F for lef t main bronchus diameters of <10 mm, 10 mm, 11 mm, 12 mm, and >12 mm, respe ctively. All DLT placements were confirmed and positioned by using fiberopt ic bronchoscopy. The tracheas of all patients were successfully intubated w ith the predicted DLT sizes. Thirty-four patients (68%) were predicted to r equire smaller DLTs (37F or smaller). Six patients were correctly predicted to receive 32F DLTs. Twelve patients (24%) received an oversized DLT, but none received an undersized DLT. The overall positive predictive value for the male and female patients was 84.4% and 61.1%, respectively. Our study s howed that CT scan measurements of the diameter of the left bronchus were e specially useful in choosing smaller DLTs. Implications: We used computer t omographic scans to measure the diameter of the left mainstem bronchus, the n selected the size of the left-sided double-lumen endobronchial tube (DLT) accordingly. We found that we could predict the sizes of the DLT fairly ac curately, especially the smaller DLTs.