TSRA Content:
Author: Martin Kosztowski, MD
For patients who are unable to wean from invasive mechanical ventilation via an endotracheal tube (ET), tracheostomy tubes should be considered. Disadvantages of long-term ET include increased sedation requirements, patient discomfort, patients have difficulty communicating, and potential for pressure-induced tracheal injury. This chapter will discuss the indications, timing and techniques for tracheostomy as well as the management of several common problems following tracheostomy placement.
Indications and Timing
The most common indication for tracheostomy is a need for long term mechanical ventilatory support in the setting of respiratory failure. However, tracheostomy also is used frequently to provide a secure airway in patients with a fixed upper airway obstruction (tumor, vocal cord paralysis, burn/caustic injury, subglottic infection, etc.). It may also be used to facilitate pulmonary toilet such as for patients with neuromuscular disease or those with an impaired mental status. While there are no stringent contraindications to tracheostomy, procedural complications are higher in patients with uncorrected coagulopathy. High levels of ventilatory support (i.e. high FiO2 or PEEP requirements) are a relative contraindication as desaturation is common when ventilation is intermittently held in these patients. In general, tracheostomy should be deferred until the patient has been medically stabilized to the greatest degree possible. The benefit of tracheostomy over orotracheal intubation is chiefly the ability to more aggressively wean the patient from mechanical ventilation. Less sedation is typically required, allowing for a more coordinated respiratory effort. Tracheostomy also allows for a patient to be 'exercised' for periods of time without mechanical ventilatory support while preserving the option to return to mechanical ventilation without a secondary procedure such as intubation.
Placement of a tracheostomy may also minimize the risk of tracheal injury (specifically stricture) caused by pressure from the ET tube cuff. However, tracheostomy may predispose to the development of subglottic stenosis. The appropriate time to perform tracheostomy for patients with respiratory failure remains controversial. Recent data from a meta-analysis supports conversion to tracheostomy following seven days of mechanical ventilation resulting in a decrease in ICU length of stay and a decrease in the duration of mechanical ventilation. However, subsequent studies have not shown the same degree of benefit with early tracheostomy. A reasonable approach is to elect early (7 day) tracheostomy for patients who have injury/illness likely to require prolonged respiratory support (blunt multi-organ trauma, neurological injury, etc.) while delaying tracheostomy until 14 days in patients who may experience recovery in the near term (pneumonia, chest surgery, etc.).
Tracheostomy Types
Two distinct methods of tracheostomy placement are currently practiced: open surgical tracheostomy (OST) and percutaneous dilatational tracheostomy (PDT). In most patients, the two approaches are equivalent in terms of both efficacy and safety. The ability to perform PDT at the bedside, without the need to schedule operating room time is a major advantage of this technique. However, OST may be a safer option in those patients who require higher levels of ventilatory support (as an anesthesiologist is present), have coagulopathy which cannot be corrected by the administration of blood products or factors, or for those patients with unfavorable anatomy.
Open Surgical Tracheostomy
There are several approaches to open tracheostomy, though the variations among the procedures are relatively minor. The patient is positioned supine with a shoulder roll between the scapulae to extend the neck. The cricoid cartilage is palpated as a landmark and an incision made at approximately the level of the third tracheal ring. The platysma is divided, and the dissection carried down to the trachea in the midline following the fat plane between the strap muscles. In some patients, the thyroid isthmus is encountered and will need to be divided (usually with a suture ligature).
Once the trachea is encountered, the 2nd or 3rd tracheal ring is identified. The tracheostomy is ideally placed at the level of the third ring. An incision is made in the trachea below the ring and extended superiorly, excising a portion of the cartilaginous ring to create a square opening in the trachea. The inspired oxygen is decreased to <50% at this point if electrocautery is to be used to minimize the risk of an airway fire. Some surgeons excise this section of anterior trachea entirely. Alternatively, the trachea maybe left intact on one side, with a suture placed through the ring to serve as a retractor to re-open the tracheotomy should the tracheostomy tube become dislodged. Once the tracheotomy has been created, ventilation is held and the ET tube is withdrawn into the hypopharynx under direct vision. The tracheostomy tube, with the obturator inside, is inserted into the airway. Once in position the obturator is exchanged for an inner cannula and a sterile on table ventilator circuit is connected. A completion bronchoscopy should be performed to verify cannula position and clear any blood from the airway.
Percutaneous Dilational Tracheostomy
The anatomic principles of PDT are identical to those of OST. A basic over-wire Seldinger technique is used to insert the tracheostomy tube. First, the ET tube is withdrawn to the hypopharynx under bronchoscopic guidance. The airway is cannulated with a needle below the 3rd tracheal ring and a guidewire inserted. Serial dilators enlarge the tract through the soft tissues to allow passage of the tracheostomy tube. The large final dilator is passed until the black mark is visible inside the airway. The dilator is then withdrawn and the tracheostomy tube (with a tapered obturator inside) passed over the wire and sheath into the trachea under direct bronchoscopic vision. Once in place, the cuff is inflated, and ventilation transferred to the tracheostomy. A completion bronchoscopy is then performed.
Complications
While tracheostomy is generally a safe and well-tolerated procedure, there are several potential complications which may arise, requiring specific management.
Dislodged Tracheostomy Tube
The appropriate management, will depend upon the maturity of the tracheostomy and the stability of the patient. For unstable patients and patients with an immature (<14 days) tracheostomy, orotracheal intubation is the safest option and should be the default for most people without any delays. In the stable patient with a mature tracheostomy tract, an attempt may be made to replace a tracheostomy tube (with an obturator in place). The tracheostomy should be confirmed prior to use to avoid insufflation of the mediastinum or hypoxia.
Subcutaneous Emphysema
Often occurs due to air leaking around the tracheostomy tube. Further inflating the cuff often solves this issue. A change to a larger tracheostomy or a tube with a longer limb may be needed for patients with a large amount of soft tissue in the neck.
Bleeding
Most bleeding immediately after tracheostomy placement is caused by small vessels in the soft tissues of the neck. This type of bleeding typically responds to direct pressure once coagulopathy is corrected. Topical hemostatic agents may be added if bleeding persists. Surgical exploration is rarely indicated. Tracheoinnominate fistula (TIF) is the most lethal complication of tracheostomy. This possibility should be considered in the setting of any large volume tracheostomy bleeding, especially with a mature tracheostomy. Avoiding low tracheotomy and minimizing cuff pressures may decrease TIF risk. Commonly, the first indication is a 'herald bleed' - a large-volume bleed which resolves spontaneously. This requires immediate investigation (CTA in a stable patient vs operative exploration with CPB standby if the clinical suspicion is high). If active bleeding is encountered, the patient should be orotracheally intubated to secure the airway. Temporary vascular control may be accomplished by inserting a finger through the tracheotomy and compressing the artery against the posterior table of the sternum. However, mortality in this circumstance is high.
Hypoxia/Poor Ventilation
Verify that the tracheostomy tube is in a good position. ET suctioning or bronchoscopy may be beneficial to clear secretions. A chest radiograph should also be assessed to evaluate alternate causes of desaturation.
Tracheostomy Downsizing and Decannulation
Patients can be considered for decannulation if the following criteria are met mechanical ventilation is no longer needed, no upper airway obstruction, minimal secretions, presence of an effective cough, and intact sensorium. There is no standard decannulation pathway, and much of this is provider dependent. The tracheostomy can either be immediately decannulated after a capping trial, or it can be sequentially downsized over the course of a few days. Most tracheocutaneous tracts should be almost completely closed by seven days after decannulation. If the tract persists for more than 3-6 months, the patient has developed a tracheocutaneous fistula. This can be a result of epithelialization of the tract and can be closed by debridement of the tract and sometimes can require a muscle flap.