title: Proper insertion depth of endotracheal tubes in adults by topographic landmarks measurements.
abstract: OBJECTIVE
  To evaluate a new method of endotracheal tube (ETT) positioning relative to carina, based on external topographic landmarks.
  
  
  METHODS
  Prospective, randomized, crossover study.
  
  
  METHODS
  Operating room, university hospital.
  
  
  METHODS
  200 American Society of Anesthesiologists (ASA) physical status I-II patients (100 women and 100 men) scheduled for elective surgery with general anesthesia.
  
  
  METHODS
  ETT insertion depth was topographically determined by adding the distance measured (in cm) from the right mouth corner to right mandibular angle to the distance measured from the right mandibular angle to a point situated on the center of a line running transversally through the middle of the sternal manubrium. This method was compared to the 21/23 cm insertion depth method.
  
  
  METHODS
  ETT position was assessed fiberoptically. The main end point was considered the percentage of ETT tips situated more than 25% higher or lower than a predetermined "best" tip position (4 cm above the carina).
  
  
  RESULTS
  There were 58.5% ETT tips positioned too closely (<3 cm above the carina) to the carina with the control method and 24% with the study method (P=0.0001). No ETT tip was too high (>5 cm above the carina). The tip-carina distance was shorter in women (2.7+/-2.5 vs 3.6+/-2.2 cm in men P=0.0001) and in those aged more than 65 years (2.8+/-2.4 vs 3.4+/-2.4 cm with age less than 65 years; P=0.012) only with the 21/23 cm method.
  
  
  CONCLUSIONS
  With our new ETT positioning method, there were fewer ETTs positioned outside the desired range of distance to carina. Our method may be especially valuable in women and in patients older than 65 years.
authors.affiliation: Department of Anesthesia, The Edith Wolfson Medical Center, Holon 58100, Israel.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Evron
authors.forename: Marian
authors.initials: M
authors.lastname: Weisenberg
authors.forename: Ethan
authors.initials: E
authors.lastname: Harow
authors.forename: Vadim
authors.initials: V
authors.lastname: Khazin
authors.forename: Peter
authors.initials: P
authors.lastname: Szmuk
authors.forename: Doron
authors.initials: D
authors.lastname: Gavish
authors.forename: Tiberiu
authors.initials: T
authors.lastname: Ezri
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000886:Anthropometry / Q000379:methods; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D005336:Fiber Optic Technology; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012044:Regression Analysis; D015203:Reproducibility of Results; D014132:Trachea / Q000033:anatomy & histology*