title: [Diagnostic utility of the hyomental distance ratio as predictor of difficult intubation at UMAE 25].
abstract: BACKGROUND
  The hyomental distance ratio is defined as the ratio of the hyomental distances in neutral position and at head extension. The aim of the study was to establish the diagnostic utility as predictor of difficult intubation.
  
  
  METHODS
  In a cross-sectional study, the assessment of the airway was performed in 70 patients (35 male and 35 female, 15-75 years old) undergoing general anesthesia with endotracheal intubation for elective surgery. We assessed Mallampati, Patil Aldreti, interincisive distance, Bellhouse Doré scales and hyomental distance ratio. Subsequently, laryngoscopy was performed and the view graded with Cormack scale. We define "difficult intubation" as Cormack III and IV. We determined the diagnostic utility of the scales and the hyomental distance ratio.
  
  
  RESULTS
  For hyomental distance ratio of ≤ 1.2 we calculated sensitivity, 60%; specificity, 20%; positive predictive value, 5%; negative predictive value, 86%; positive likelihood ratio of 0.75 and negative likelihood ratio of 2.
  
  
  CONCLUSIONS
  The hyomental distance ratio, as predictor of difficult intubation, has little utility.
authors.affiliation: Departamento de Anestesiología. Unidad Médica de Alta Especialidad Hospital de Especialidades N.o 25 Centro Médico Nacional Noreste (UMAE 25). Instituto Mexicano del Seguro Social, Monterrey, N.L., México.
authors.forename: Jair Marino
authors.initials: JM
authors.lastname: Montemayor-Cruz
authors.affiliation: Departamento de Anestesiología. Unidad Médica de Alta Especialidad Hospital de Especialidades N.o 25 Centro Médico Nacional Noreste (UMAE 25). Instituto Mexicano del Seguro Social, Monterrey, N.L., México.
authors.forename: Rosa Ma
authors.initials: RM
authors.lastname: Guerrero-Ledezma
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D058109:Airway Management / Q000379:methods; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006928:Hyoid Bone / Q000033:anatomy & histology; D007442:Intubation, Intratracheal / Q000379:methods*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology; D008875:Middle Aged; D011237:Predictive Value of Tests; D055815:Young Adult