There are both advantages and disadvantages of tracheostomy compared with translaryngeal intubation (Table 33-4). No clear evidence or consensus exists for when a tracheostomy should replace an endotracheal tube. Using percutaneous techniques, the modern tracheostomy procedure is a relatively simple bedside procedure. Although many patients tolerate endotracheal intubation for weeks without complications, prolonged intubation increases the risk of glottic injury. On the other hand, tracheostomy increases the risk of tracheal stenosis. Tracheostomy is usually reserved for patients requiring long-term ventilatory support and for those needing long-term airway protection (eg, patients with neurologic disease) or those with multiple failed attempts to extubate. Some failure-to-wean patients may be successfully liberated from mechanical ventilation after tracheostomy. This may relate to less resistance through the tracheostomy tube, less dead space, increased ability to remove secretions, and improved patient comfort.
Table 33-4Comparison of Advantages of Translaryngeal Intubation and Tracheostomy During Prolonged Ventilatory Support ||Download (.pdf) Table 33-4 Comparison of Advantages of Translaryngeal Intubation and Tracheostomy During Prolonged Ventilatory Support
|Translaryngeal intubation ||Tracheostomy |
Easy and rapid initial insertion
Avoids surgical procedure
Lower cost of initial placement
Ease of reinsertion if dislodged
Reduced laryngeal injury
Better secretion removal with suctioning
Lower incidence of tube obstruction
Less oral injury
Improved patient comfort
Better oral hygiene
Improved ability to speak
Preservation of glottic competence
Better swallow allowing oral feeding
Lower resistance to air flow
Less tube dead space
Lower work of spontaneous breathing
More rapid weaning from mechanical ventilation
Types of Tracheostomy Tubes
Tracheostomy tubes are available in a variety of sizes and styles from several manufacturers. The dimensions of tracheostomy tubes are given by their inner diameter, outer diameter, length, and curvature. Proper fit of the tube is an important consideration, as a poorly fitting tube can lead to distal obstruction in the trachea and the formation of granulation tissue. Tracheostomy tubes can be angled or curved to improve the fit of the tube in the trachea. Extra proximal length tubes facilitate placement in patients with large necks, and extra distal length tubes facilitate placement in patients with tracheal anomalies. Some tubes have a spiral wire reinforced flexible design, and some have an adjustable flange design to allow bedside adjustments to meet extra length tracheostomy tube needs. An inner cannula is used on some tracheostomy tube designs. The inner cannula can be removed for cleaning. Cuffs on tracheostomy tubes include high-volume low-pressure cuffs, tight-to-shaft cuffs, and foam cuffs. The fenestrated tracheostomy tube has an opening in the posterior portion of the tube, above the cuff, which allows the patient to breathe through the upper airway when the inner cannula is removed. Some tracheostomy tubes have a port above the cuff that allows subglottic aspiration of secretions.
Speaking With a Tracheostomy Tube
For mechanically ventilated patients with a tracheostomy, the cuff is deflated and the leak that results through the upper airway can be used to facilitate speech. Good-quality voice can result in many patients by using higher levels of PEEP (which increases leak during exhalation), a longer inspiratory time, and a higher tidal volume set on the ventilator to compensate for the volume lost due to leak. For many patients voice quality is adequate without the need for a speaking valve, improving safety if the upper airway becomes obstructed when a speaking valve is used.
A speaking valve allows the patient to inhale through the tracheostomy tube but exhale through the upper airway. A speaking valve is more commonly used when the patient no longer requires positive pressure ventilation. When a speaking valve is placed, it is important that the patient can adequately exhale through the upper airway. This can be assessed by measurement of tracheal pressure when the valve is placed. If the expiratory tracheal pressure is greater than 10 cm H2O, the placement of a smaller tube or the presence of upper airway pathology should be considered.
For patients who do not tolerate cuff deflation, a speaking tracheostomy tube can be used. With this tube, gas flow is introduced above the cuff to provide flow past the vocal cords and, thus, allow speech. Cuff deflation, with or without a speaking valve, usually produces better voice than a speaking tracheostomy tube.
In patients no longer requiring mechanical ventilation, level of consciousness, cough effectiveness, secretions, and oxygenation are considered important determinants of decannulation readiness. A stepwise approach is usually followed. The patient is first observed for tolerance of cuff deflation, followed by tolerance of a speaking valve and tolerance of capping. If the patient tolerates a capped tracheostomy tube for 24 to 72 hours, strong consideration should be given to decannulation. Decannulation failure is commonly defined as the need to reinsert an artificial airway within 48 to 96 hours following planned tracheostomy removal.