Tracheal palpation to assess endotracheal tube depth: an exploratory study

  • William P. McKayEmail author
  • Jim Klonarakis
  • Vladko Pelivanov
  • Jennifer M. O’Brien
  • Chris Plewes
Reports of Original Investigations



Correct placement of the endotracheal tube (ETT) occurs when the distal tip is in mid-trachea. This study compares two techniques used to place the ETT at the correct depth during intubation: tracheal palpation vs placement at a fixed depth at the patient’s teeth.


With approval of the Research Ethics Board, we recruited American Society of Anesthesiologists physical status I-II patients scheduled for elective surgery with tracheal intubation. Clinicians performing the tracheal intubations were asked to “advance the tube slowly once the tip is through the cords”. An investigator palpated the patient’s trachea with three fingers spread over the trachea from the larynx to the sternal notch. When the ETT tip was felt in the sternal notch, the ETT was immobilized and its position was determined by fibreoptic bronchoscopy. The position of the ETT tip was compared with our hospital standard, which is a depth at the incisors or gums of 23 cm for men and 21 cm for women. The primary outcome was the incidence of correct placement. Correct placement of the ETT was defined as a tip > 2.5 cm from the carina and > 3.5 cm below the vocal cords.


Movement of the ETT tip was readily palpable in 77 of 92 patients studied, and bronchoscopy was performed in 85 patients. Placement by tracheal palpation resulted in more correct placements (71 [77%]; 95% confidence interval [CI] 74 to 81) than hospital standard depth at the incisors or gums (57 [61%]; 95% CI 58 to 66) (P = 0.037). The mean (SD) placement of the ETT tip in palpable subjects was 4.1 (1.7) cm above the carina, 1.9 cm (1.5-2.3 cm) below the ideal mid-tracheal position.


Tracheal palpation requires no special equipment, takes only a few seconds to perform, and may improve ETT placement at the correct depth. Further studies are warranted.


Vocal Cord Correct Placement Sternal Notch Esophageal Intubation Cricothyroid Membrane 
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La palpation trachéale pour évaluer la profondeur de la sonde endotrachéale: une étude exploratoire



On définit le bon positionnement de la sonde endotrachéale (SET) lorsque l’extrémité distale de la SET se situe à mi-trachée. Cette étude compare deux techniques pour placer la SET à la bonne profondeur pendant l’intubation: la palpation trachéale et le positionnement à une profondeur fixe par rapport aux dents du patient.


Après avoir obtenu le consentement du Comité d’éthique de la recherche, nous avons recruté des patients de statut physique I-II selon la classification de l’American Society of Anesthesiologists devant subir une chirurgie non urgente avec intubation trachéale. On a demandé aux cliniciens réalisant les intubations trachéales « d’avancer la sonde lentement une fois que l’extrémité a dépassé les cordes vocales ». Un chercheur a palpé la trachée du patient à l’aide de trois doigts étendus sur la trachée du larynx à l’échancrure sternale. Une fois l’extrémité de la SET sentie dans l’échancrure sternale, la SET a été immobilisée et sa position a été déterminée par bronchoscopie par fibres optiques. La position de l’extrémité de la SET a été comparée à notre norme hospitalière, soit une profondeur aux incisives ou aux gencives de 23 cm chez les hommes et de 21 cm chez les femmes. Le critère d’évaluation principal était l’incidence de bon positionnement. Un bon positionnement de la SET était défini si l’extrémité était située à > 2,5 cm de la carène et > 3,5 cm sous les cordes vocales.


Le mouvement de l’extrémité de la SET était facile à palper chez 77 des 92 patients à l’étude, et la bronchoscopie a été réalisée chez 85 patients. Le positionnement par palpation trachéale a entraîné davantage de bons positionnements (71 [77 %]; intervalle de confiance [IC] 95 % 74 à 81) par rapport à la profondeur standardisée dans notre hôpital par rapport aux incisives ou aux gencives (57 [61 %]; IC 95 % 58 à 66) (P = 0,037). Le positionnement moyen (ET) de l’extrémité de la SET chez les patients palpables était situé à 4,1 (1,7) cm au-dessus de la carène, 1,9 cm (1,5-2,3 cm) sous la position idéale à mi-trachée.


La palpation trachéale ne nécessite aucun matériel spécial, ne prend que quelques secondes, et pourrait améliorer le positionnement de la SET à la bonne profondeur. Des études supplémentaires sont nécessaires.


This study was funded by the Department of Anesthesia, University of Saskatchewan. No author has any commercial or other affiliation that is, or may be perceived to be, a conflict of interest.

Conflicts of interest

None declared.


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Copyright information

© Canadian Anesthesiologists' Society 2013

Authors and Affiliations

  • William P. McKay
    • 1
    Email author
  • Jim Klonarakis
    • 1
  • Vladko Pelivanov
    • 1
  • Jennifer M. O’Brien
    • 1
  • Chris Plewes
    • 2
  1. 1.Department of Anesthesia, RUHUniversity of SaskatchewanSaskatoonCanada
  2. 2.Department of RadiologyUniversity of SaskatchewanSaskatoonCanada

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