title: Tracheal size variability is associated with sex: implications for endotracheal tube selection.
abstract: OBJECTIVE
  Whereas selection of endotracheal tube (ETT) size in pediatric patients benefits from predictive nomograms, adult ETT sizing is relatively arbitrary. We sought to determine associations between cervical tracheal cross-sectional area (CTCSA) and clinical variables.
  
  
  METHODS
  One hundred thirty-two consecutive patients undergoing noncontrasted chest computed tomography (CT) at a single tertiary care institution from January 2010 to June 2011 were reviewed. Patients with improper CT technique, endotracheal intubation, and pulmonary/tracheal pathology were excluded. Tracheal luminal diameters in anteroposterior (D1) and transverse (D2) were measured 2 cm inferior to the cricoid and used to determine CTCSA = π*D1*D2*¼. The demographic variables of age, height, weight, and body mass index (BMI) were tested for association with CTCSA by Spearman correlation. Wilcoxon rank-sum test was used to compare CTCSA by race and sex. Multivariate linear regression was performed including all clinical variables.
  
  
  RESULTS
  There were 91 patients who met inclusion criteria. There was no correlation between age, weight, or BMI and CTCSA. There was a significant positive correlation between patient height and CTCSA (P = .001, R = 0.35); however, this was confounded by sex. Female patients had significantly smaller CTCSA (mean = 241 mm(2)) compared to male patients (mean = 349 mm(2), P < .001). Multivariate linear regression stratified by sex revealed that height is correlated with CTCSA only in males (P = .028). Males also had more variability in CTCSA (SD 118.6) compared to females (SD 65.5).
  
  
  CONCLUSIONS
  Our data suggest that selection of ETT size in male patients should include height as a predictive factor. For female patients, it may be appropriate to select a uniformly smaller diameter ETT size.
authors.affiliation: Department of Otolaryngology and Center for Voice, Airway and Swallowing, Georgia Regents University, Augusta, Georgia, USA.
authors.forename: Arunabha
authors.initials: A
authors.lastname: Karmakar
authors.affiliation: Department of Otolaryngology and Center for Voice, Airway and Swallowing, Georgia Regents University, Augusta, Georgia, USA.
authors.forename: Mariah B
authors.initials: MB
authors.lastname: Pate
authors.affiliation: Department of Otolaryngology and Center for Voice, Airway and Swallowing, Georgia Regents University, Augusta, Georgia, USA.
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Solowski
authors.affiliation: Department of Otolaryngology and Center for Voice, Airway and Swallowing, Georgia Regents University, Augusta, Georgia, USA.
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Postma
authors.affiliation: Department of Otolaryngology and Center for Voice, Airway and Swallowing, Georgia Regents University, Augusta, Georgia, USA Center for Biotechnology and Genomic Medicine, Georgia Regents University, Augusta, Georgia, USA pweinberger@gru.edu.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Weinberger
mesh_terms: D000367:Age Factors; D001827:Body Height; D015992:Body Mass Index; D004867:Equipment Design; D004865:Equipment and Supplies, Hospital; D005260:Female; D005845:Georgia; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009929:Organ Size; D018579:Patient Selection; D044469:Racial Groups; D012189:Retrospective Studies; D012737:Sex Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D014132:Trachea / Q000473:pathology*
keywords: airway management; intratracheal intubation; trachea; tracheal stenosis