Tracheostomy

Indications and Contraindications

Despite its long history and frequent use, the indications and timing for tracheostomy remain controversial. Common indications for tracheostomy include respiratory insufficiency requiring prolonged mechanical support, uncontrolled tracheobronchial secretions, relief of upper airway obstruction, and for patients undergoing a laryngectomy.1 Requirement for prolonged mechanical support due to respiratory failure is the least clearly defined indication for tracheostomy. Although it is generally agreed that conversion of an endotra-cheal tube to a tracheostomy is indicated at some point during a prolonged stay in the ICU, the exact timing remains controversial. The decision to convert to a tracheostomy must be individualized and the risk-benefit ratio must be taken into account. Generally, if a patient remains intubated for 1 week and it is clear that he or she will not be extubated at anytime in the near future, a tracheostomy should be performed, assuming an acceptable surgical risk. Beyond this time period, the risk of severe laryngeal injury, need for effective pulmonary toilet, improved patient comfort, and finally, the need for a stable airway begin to shift the risk-benefit ratio toward a tracheostomy.2-4

Anatomy

The trachea is a 12-cm fibrocartilaginous tube, which extends from the larynx to the roots of the lungs. There are 18-22 cartilaginous rings. The isthmus of the thyroid gland lies over the second and third tracheal rings. The inferior thyroid veins form a plexus anterior to the trachea and inferior to the isthmus. A small thyroid ima artery is present in about 10 percent of patients and ascends to the inferior border of the isthmus. The brachiocephalic trunk lies to the right of the trachea at the root of the neck. In infants and children the thymus lies anterior to the inferior part of the trachea.

Procedure

A tracheostomy is performed by making a 3-cm transverse incision over the second or third tracheal ring. To identify this region the surgeon palpates the cricoid cartilage and makes an incision 1.5 cm inferior to it. The platysma is then divided and the strap muscles are separated vertically in the midline. The thyroid isthmus is then retracted superiorly. It is important to keep in mind the following important anatomic structures to avoid possible injury: the inferior thyroid veins, thyroid ima artery, left brachiocephalic vein, jugular venous arch, pleurae, and the thymus gland specifically in infants and children. After the second tracheal ring is identified, securing sutures are placed on either side of the midline between the first and second cartilages and used to retract the trachea upward. A scalpel blade is then used to make a vertical, midline incision through the second and third tracheal rings. A tracheal dilator is subsequently used to spread the divided tracheal cartilages while a lubricated tracheostomy tube is inserted through the newly created stoma. The tracheostomy tube is advanced as the endotracheal tube is carefully withdrawn. The tracheostomy tube is then confirmed to be in adequate position and subsequently sutured to the skin and tied into place with trachea around the patient's neck (Fig. 18-12).

i^j Skin incision

Figure 18-12 Technique of Tracheostomy. (Source: Adapted from Townsend CM, Beauchamp RD, Evers BM, et al. Sabiston Textbook of Surgery, 17th ed. The Netherlands: Elsevier, 2004.)

Complications

The complication rate following a tracheostomy is approximately 5-6 percent.2 Acute complications of tracheostomy primarily include bleeding and infection.

Tracheoinnominate artery fistula is a rare long-term complication that occurs when a tracheostomy tube erodes into the innominate artery, resulting in life-threatening hemorrhage. An impending tracheoinnominate artery erosion may be heralded by the finding of bright-red blood during tracheal tube suctioning. The diagnosis may be confirmed with increased hemorrhage on temporary deflation of the tracheal cuff. Acutely, hemorrhage is controlled by either overinflating the tracheal cuff or by inserting a finger through the tracheostomy stoma and applying digital compression against the sternum while the patient is transferred to the operating room for repair.

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