TRACHEOSTOMY
Tracheostomy is a surgical procedure which consists of making an incision on the anterior aspects (front) of the neck and opening a direct airway through a incision in the trachea.
Indication of tracheostomy
To provide an artificial airway in place of orotracheal or nasotracheal intubation. This may be provide better patient comfort, avoid vocal cord, mouth or nasal trauma or, in an emergency, bypass acute upper airway obstruction. The optimal time to perform a tracheotomy in an intubated patient is not known; a prospective rendomised study ( the 'TracMan' trial) id underway in the UK. Reduced need foe sedation, the potential to eat, drink and speak, and facilitation of mouth care are all advantages.
Percutaneous tracheostomy
Percutaneous tracheostomy can be performed in the ICU. Coagulopathy should be excluded or treated first. Subcutaneous tissues are infiltrated with 1% lidocaine and epinephrine (adrenaline). After a 1-1.5 cm midline skin crease incision, the subcutaneous tissue is blunt-dissected to the anterior tracheal wall. The ET tube tip is withdrawn to the level of the vocal cords. The trachea is then punctured in the midline with a 14G needle between the 1st and 2nd tracheal cartilages (or lower), allowing guide wire insertion. The stoma is created by dilatation to 32-36 Fr (Ciagli technique) or by a guided forceps dilating tool ( Schachner-Ovill technique). In the former case, the tracheostomy tube is introduced over an appropriate-sized dilator, and in the latter, through the open dilating tool. End tidal CO2 monitoring confirms adequate ventilation during the procedure. Fibreoptic bronchoscopy may be used to confirm correct tracheal placement and no trauma to the posterior tracheal wall.
Complications of tracheostomy
The main early complication is bleeding from vessels anterior to the trachea. This is usually controlled with direct pressure or, occasionally, sutures. Bleeding into the trachea may result in clot obstruction of the airway; endotracheal suction is usually effective. Paratracheal placement should be rare, but promptly recognised by the inability to ventilate the lungs. Later complications include tracheostomy tube displacement, stomal infection, and tracheal stenosis. Rare complications include tracheo-esophageal fistula due to trauma or pressure necrosis of the posterior tracheal wall, or erosion through the lateral tracheal wall into a blood vessel.
Maintenance of a tracheostomy
Since the upper air passages have been bypassed, artificial humidification is required. Cough is less effective without a functioning larynx so regular tracheal suction will be necessary. Natural laryngeal PEEP is lost with a tracheostomy . The risk of basal atelectasis can be overcome with CPAP or attention to respiratory exercises that promote deep breathing. After 3-5, the tracheostomy tube can be safely replaced.
Tracheostomy tube removal
Before removing the tube, ensure the upper airway is patient, either by allowing the patient to exhale passed an occluded tube or by visualisation.
Tracheostomy tubes
Standard high volume, low pressure cuff
Fenestrated with or without cuff
Usually where airway protection is not a primary concern. May be closed during normal breathing while providing intermittent suction access.
Fenestrated, with inner tube
As above but with an inner tube to facilitate closure of the fenestration during intermittent mechanical ventilation.
Fenestrated, with speaking valve
Inspiration allowed through the tracheostomy to reduce dead space and inspiratory resistance. Expiration through the larynx via the fenestration, allowing speech and the advantages of laryngeal PEEP.
Adjustable flange
Accommodates extreme variations in skin to trachea depth while ensuring the cuff remains central in the trachea.
Pitt speaking tube
A non-fenestrated, cuffed tube for continuous mechanical ventilation and airway protection with a port to direct airflow above the cuff to the larynx. When airflow is directed through the larynx, some patients are able to vocalise.
Passy- Muir speaking valve
This expiratory occlusive valve is placed onto the tracheostomy tube to permit inspiration through the tracheostomy and expiration through the glottis. The tracheostomy tube cuff must be first deflated. The valve allows phonation, facilitates swallowing, and may reduce aspiration. Small studies have suggested that it may reduce the work of breathing. The potential tidal volume drop through cuff deflation makes this valve only suitable in those patients requiring no ( or relatively low level) invasive ventilatory support.
Silver tube
An uncuffed tube used occasionally in ENT practice to maintain a tracheostomy fistula.
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