Tracheostomy

Chapter 18 Tracheostomy



Mack Fudge, DVM, MPVM, DACVECC



KEY POINTS



• Continuous patient monitoring and intensive nursing care are critical to successful tracheostomy tube management and patient comfort.

• Care must be taken to prevent damage to the left recurrent laryngeal nerve when a tracheotomy is performed.

• Long stay sutures placed around the cartilage rings adjacent to the tracheotomy incision allow routine tube replacement and may be lifesaving if the tube becomes occluded or dislodged.


INTRODUCTION


Temporary tracheostomy is indicated for life-threatening upper airway obstruction, oral or pharyngeal surgery when oral endotracheal intubation is undesirable, airway obstruction from edema and inflammation after pharyngeal or laryngeal surgery, long-term ventilator support for critically ill patients, and removal of tracheal foreign bodies.1 Access to the trachea provided by the tracheostomy allows air to enter distal to obstructions and reduces damage to the oral cavity from prolonged intubation.2,3



TRACHEOSTOMY TUBE SELECTION


Numerous tracheostomy tubes are commercially available. They can be cuffed or uncuffed tubes and may or may not have an inner cannula. The requirement for a tube cuff will depend on individual patient factors. In most cases a cuff is not required, and the use of an uncuffed tube or keeping the tube cuff deflated may reduce the likelihood of tracheal injury. A cuff may be considered desirable in patients that require positive-pressure ventilation, although this mode may also be feasible with uncuffed tubes. A tube cuff may make it necessary to use a slightly smaller tracheostomy tube than would be possible without the cuff.


A removable inner cannula allows for easy and effective tube maintenance and is considered desirable. The inner cannula can be removed briefly for cleaning without disrupting the airway integrity. Unfortunately, smaller tubes cannot be made with an inner cannula. In the absence of an inner cannula, the entire tracheostomy tube should be replaced every 24 hours (more often if indicated) to prevent occlusion with accumulated secretions.


The size of the tracheostomy tube chosen is based on the diameter of the patient’s airway. The largest tube that can be readily accommodated by the trachea is selected. Note that the size of tracheostomy tube does not correspond with the scale used to size endotracheal tubes. An estimate of the appropriate tracheostomy tube size usually can be made by evaluation of the inner lumen diameter of the trachea on a lateral cervical radiograph.


Tracheostomy tubes can also be fenestrated. The fenestration is an opening in the tube that allows air flow through to the upper airway if the external opening is occluded. In human patients this feature is used to enable speech. The utility of a fenestrated tube in veterinary patients is questionable. A fenestrated tube cannot be used if positive-pressure ventilation is required.


If a tracheostomy tube is not immediately available, an endotracheal tube can be shortened and used effectively in the interim.



SURGICAL TECHNIQUE


Temporary tracheostomy is best performed in a controlled manner with the patient under general anesthesia with an orotracheal tube in place. The animal is placed in dorsal recumbency with the neck carefully extended for exposure of the surgical site. The neck can be elevated from the table by placing it on a cushion. Routine surgical preparation of the ventral cervical region is performed.


A 2- to 5-cm ventral cervical midline skin incision is made extending from the cricoid cartilage toward the sternum. The sternohyoid muscles are separated along their midline with blunt dissection and retracted laterally. The peritracheal connective tissue is removed from the region of the tracheotomy site. Throughout the procedure care must be taken to prevent dissection lateral to the trachea to prevent injury to the left recurrent laryngeal nerve or disruption of tracheal blood supply.


Various tracheal incisions have been proposed. Although most surgeons believe that a transverse approach is least likely to cause tracheal stenosis, studies suggest that the type of incision plays a minor role in the development of stenosis.1,3-5 The two common surgical approaches for temporary tracheotomy are transverse and vertical incisions.



Transverse Incision


The annular ligament between the third and fourth or fourth and fifth tracheal rings is incised, taking care not to extend the incision longer than 50% of the tracheal circumference. Extreme care must be taken to avoid the left recurrent laryngeal nerve. A small ellipse of cartilage from each tracheal cartilage adjacent to the tracheotomy incision can be made to help reduce tracheal irritation and inflammation. Long loops of suture are placed around the tracheal rings adjacent to the incision to facilitate retraction of the trachea and future replacement of the tube after cleaning (Figure 18-1).1,2


image

Figure 18-1 Transverse incision tracheostomy.

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Tracheostomy

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