title: Predicting the size of a double-lumen endobronchial tube using computed tomographic scan measurements of the left main bronchus diameter.
abstract: 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 require smaller DLT sizes. Fifty consecutive Asian adults aged 17-80 yr with preoperative chest CT scans undergoing elective thoracic surgery were entered into the study. The measurements of the left main bronchus diameter were made by using the electronic calipers of the spiral scanner to the nearest millimeter. The sizes of DLT selected were 32F, 35F, 37F, 39F, and 41F for left main bronchus diameters of <10 mm, 10 mm, 11 mm, 12 mm, and >12 mm, respectively. All DLT placements were confirmed and positioned by using fiberoptic bronchoscopy. The tracheas of all patients were successfully intubated with the predicted DLT sizes. Thirty-four patients (68%) were predicted to require 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 showed that CT scan measurements of the diameter of the left bronchus were especially useful in choosing smaller DLTs.
  
  
  CONCLUSIONS
  We used computer tomographic scans to measure the diameter of the left mainstem bronchus, then 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 accurately, especially the smaller DLTs.
authors.affiliation: Department of Anesthesia, Singapore General Hospital and Tan Tock Seng Hospital, Singapore. markchow@bigfoot.com
authors.forename: M Y
authors.initials: MY
authors.lastname: Chow
authors.forename: B L
authors.initials: BL
authors.lastname: Liam
authors.forename: C H
authors.initials: CH
authors.lastname: Thng
authors.forename: B K
authors.initials: BK
authors.lastname: Chong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001980:Bronchi / Q000033:anatomy & histology*; D001995:Bronchography; D020680:Bronchoscopes; D002138:Calibration; D017558:Elective Surgical Procedures; D004582:Electronics, Medical / Q000295:instrumentation; D004867:Equipment Design; D005260:Female; D005336:Fiber Optic Technology; D005544:Forecasting; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D019616:Thoracic Surgical Procedures; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000033:anatomy & histology