title: Measurement of left mainstem bronchus using multiplane CT reconstructions and relationship between patient characteristics or tracheal diameters and left bronchial diameters.
abstract: OBJECTIVE
  To measure the tracheal diameters (TDs) [transverse (Tr) TD, and anteroposterior (AP) TD] and left main bronchus diameters (LBDs) [Tr and AP] using multiplane CT scan reconstructions with a tridimensional correction of the declination. To evaluate the relationship between clinical variables and CT scan diameters of the tracheobronchial tree. To aid in the selection of a double-lumen tube of appropriate size.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Private and university hospitals.
  
  
  METHODS
  A total of 206 patients (105 women and 101 men) undergoing a CT scan for medical investigations or preoperative evaluation.
  
  
  METHODS
  No intervention.
  
  
  RESULTS
  TDs and LBDs are greater in men (p < 0.001). The Tr-TD is smaller than AP-TD for men (p < 0.001). The Tr-LBD is greater than AP-LBD in both sexes (p < 0.001). In men, height, Tr-TD, and AP-TD are predictive factors for Tr-LBD, while Tr-TD and AP-TD are the only predictive factors for AP-LBD. In women, Tr-TD and AP-TD are the only predictive factors for Tr-LBD and AP-LBD. The smallest LBD (ie, the lesser of the Tr-LBD or the AP-LBD [called the smallest LBD]) is the Tr-LBD in 25.2% of the cases. The mean (+/- SD) ratio of the smallest LBD/Tr-TD is 0.70 +/- 0.14 for men and 0.65 +/- 0.12 for women. The estimated (Est) LBD is calculated using this ratio. The mean value for Est-LBD minus the smallest LBD is 1.6 +/- 1.3 mm, and this difference is < 1 mm in 40% of male patients and 39% of female patients.
  
  
  CONCLUSIONS
  In conclusion, the left main bronchus is most often elliptic, and the smallest LBD cannot be accurately evaluated using patient characteristics or a ratio from TD.
authors.affiliation: Groupe des Anesthésistes Réanimateurs de l'Hôpital Privé d'Antony, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Olivier
authors.forename: David
authors.initials: D
authors.lastname: Hayon-Sonsino
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Convard
authors.forename: Pierre-Antoine
authors.initials: PA
authors.lastname: Laloë
authors.forename: Marc
authors.initials: M
authors.lastname: Fischler
mesh_terms: D001980:Bronchi / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000033:anatomy & histology*