title: Predicting the depth of insertion of left-sided double-lumen endobronchial tubes.
abstract: OBJECTIVE
  To analyze the parameters that predict the depth of insertion of a left-sided double-lumen tube (DLT) and to assess the accuracy of the parameters after intubation.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Tertiary-care hospital.
  
  
  METHODS
  Patients undergoing 1-lung ventilation for thoracic surgery (n = 240).
  
  
  METHODS
  In the first 121 patients, the ideal depth of insertion was verified using fiberoptic bronchoscopy in the lateral position. Multiple regression analysis was used to find the correlation of this depth of insertion to the patients' height, weight, age, and the clavicular-to-carinal distance of the trachea measured from the chest radiograph. Another 119 patients were studied in whom the DLT was inserted blindly using the best regression line. The accuracy of the technique was assessed by fiberoptic bronchoscopy.
  
  
  RESULTS
  The depth of DLT insertion correlated significantly (p < 0.05) only with the height and clavicular-to-carinal distance of the trachea of the patients with the best regression line: Depth of insertion (cm) = 0.75 x clavicular-to-carinal distance of trachea (cm) + 0.112 x height (cm) + 6 with R(2) = 0.62 and p < 0.001. Using this best regression line, the DLT was placed in an acceptable position in 93 patients in the lateral position (positive predictive value of 78.2%) without further intraoperative adjustments.
  
  
  CONCLUSIONS
  The ideal depth of insertion of the left-sided DLT correlated significantly with patients' height and clavicular-to-carinal distance of the trachea. The best regression line enabled the left-sided DLT to be placed in an acceptable position without complications nearly 80% of the time.
authors.affiliation: Department of Anaesthesia and Surgical Intensive Care Unit, Singapore General Hospital, Singapore. markchow@bigfoot.com
authors.forename: Mark Yew-Hoong
authors.initials: MY
authors.lastname: Chow
authors.forename: Meng-Huat
authors.initials: MH
authors.lastname: Goh
authors.forename: Lian-Kah
authors.initials: LK
authors.lastname: Ti
mesh_terms: D000328:Adult; D000368:Aged; D001827:Body Height; D001980:Bronchi / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013223:Statistics as Topic; D019616:Thoracic Surgical Procedures; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000601:surgery