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(palpation of cricoid cartilage)
Vacanti and Roberts described a method of blind intubation that uses palpation of the cricoid cartilage to assist placement of a styletted tracheal tube.
A standard tube stylet is placed within a tracheal tube to within 5 mm of the end, and bent at a 60 degree angle (presumably just proximal to the cuff ). The patient’s head rests on the bed without any additional support, placed in full atlanto-occipital extension. An assistant subluxes the mandible forward by lifting at the angle of the mandible. Intubator stands at the side of the patient and introduces the tracheal tube into the corner of the mouth with his or her dominant hand. The tube and stylet are advanced along the curvature of the tongue while probing with the tube tip; slight pressure is put on the cricoid cartilage with the forefinger and thumb of the other hand. Tracheal placement can be appreciated by palpation and by the clicks felt as the tube is advanced into the trachea. If entry into the trachea is not accomplished, the tube tip can be directed left or right as needed. Vacanti found that this technique was effective in intubating 49/50 patients in less than a minute. Prior to testing the technique blindly, Vacanti performed fiberoptic evaluation of the technique and concluded that mandible subluxation was critical for lifting the epiglottis off of the posterior pharyngeal wall. Tube insertion in the corner of the mouth made for a short distance down to the larynx, and allowed the tube to remain bent appropriately. Although a standard stylet was used, a lighted stylet or optical stylet could also be used in this manner, and would provide the additional benefit of trans-illumination or direct visualization.
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| A tracheal tube can also be placed with direct palpation of the epiglottis or larynx. It is easiest in patients with no teeth and a short distance from the mouth to the larynx. Children and edentulous adults are ideal for this procedure. It should not be attempted unless the patient is in cardiac arrest, is pharmacologically paralyzed, or for some other reason is not capable of biting.
A stylet is useful for pre-molding the tube and stylet into a large arc, beginning at the middle of the tube and extending to the tip. The stylet should be well lubricated within the tracheal tube to facilitate removal.
The procedure is most easily performed from the patient’s left side (assuming operator is right-hand dominant). Head extension lengthens the distance from the mouth to the trachea and should be avoided. Head and neck flexion may be beneficial, as long as mouth opening is not restricted. Tongue traction may permit further advancement of the fingers. The index and long fingers of the operator’s left hand are slid over the surface of the tongue until the tip of the epiglottis or the posterior cartilages of the larynx is appreciated. The right hand is then used to rotate the pre-molded tracheal tube and stylet downward between the fingers of the left hand. The fingertips help direct the tip anteriorly into the larynx.
While the left hand stabilizes the tube, the stylet is withdrawn and the tube advanced into the trachea to the proper depth. In order to obtain proficiency with digital intubation, the clinician must have a good appreciation of what the epiglottis feels like while wearing a latex glove. Being able to palpate the posterior cartilages of the larynx can guide correct placement. Appreciating the feel of the epiglottis or being able to reach the posterior cartilages is quite difficult in many adult patients, especially those with prominent upper dentition. Conversely, this is not the case in small children. In practice, digital intubation is rarely used. Potentially in situations of massive bleeding (or other fluids) it theoretically has a role when direct laryngoscopy visualization or other imaging based techniques are impossible. |
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