Queen Mother Hospital for Animals, Royal Veterinary College, North Mymms, UK
Tracheostomy tubes may be indicated when upper airway swelling, inflammation, trauma, neoplasia or laryngeal paralysis is present. Some of these conditions may be manageable with sedation alone (e.g., laryngeal paralysis); however, if the patient has severe dyspnoea, hypoxaemia or hypercapnia despite sedation and supplemental oxygen therapy, then endotracheal (ET) or tracheostomy tubes are indicated. Sometimes ET tube placement is sufficient for the upper airway obstruction to be resolved medically or surgically; however, if recovery from the above condition is likely to be prolonged (e.g., >24 hours), tracheostomy tube placement should be considered. Tracheostomy tubes can also be used during mechanical ventilation, as it allows lower doses of sedative agents as animals tolerate tracheostomy tubes better than ET tubes, and may facilitate weaning off the ventilator in patients with upper airway disease. Another indication for tracheostomy tubes would be during intraoral procedures. Patients with tracheostomy tubes must be monitored 24 hours a day, as acute tube obstruction can occur. They should also be avoided if possible in very small animals due to increased risk of complications. It is rare the emergency 'slash' tracheostomy is required, as most of the time, placing an endotracheal tube (if necessary with the aid of a stylet) is possible.
Types of Tracheostomy Tubes
There are several types of tracheostomy tubes available. A cuffed tube is necessary if ventilation is being performed; otherwise, an uncuffed tube should be used, as it is less traumatic and less likely to accumulate secretions. Larger tubes can come with an inner cannula which can be removed intermittently for cleaning; however, smaller tubes do not have inner cannulas. A tracheostomy tube can be made from an ET tube. The size of tracheostomy tubes does not correspond to ET tubes. The outer diameter should be able to accommodate the tracheal diameter without being traumatic, and the inner diameter large enough to minimise obstruction.
1. Place the patient in dorsal recumbency while intubated under general anaesthesia. Clip and aseptically prepare a large area caudal to the larynx.
2. Make a midline incision just caudal to the larynx over the 2nd and 3rd tracheal rings.
3. With self-retaining retractors in place, dissect through the subcutaneous tissue until you can identify the fascia between the two sternohyoideus muscles. Staying completely midline will help with this.
4. Bluntly dissect between the sternohyoideus muscles using Metzenbaum scissors, avoiding the thyroidea vein.
5. Reposition the self-retaining retractors below the sternohyoideus muscles to expose the trachea. Using a scalpel blade, incise the interannular ligament between the 2nd and 3rd tracheal rings, no greater than 50% of the circumference.
6. Place separate stay sutures using non-absorbable suture material around the 2nd and 3rd tracheal rings. Do not make a knot around the tracheal ring. Keep a large loop of suture material, and place mosquito haemostats at the end of the stay sutures.
7. The stay suture around the 2nd tracheal ring is pulled cranially, and the suture around the 3rd tracheal ring is pulled caudally to open the trachea. Remove the ET tube, and quickly insert the tracheostomy tube.
8. Leave the stay sutures in place and label them 'cranial' and 'caudal' for easy manipulation. The wound does not need to be sutured. Place umbilical tape around each flange of the tracheostomy tube and tie behind the neck.
Tracheostomy Tube Care
Tracheostomy tube care should be provided every 1–4 hours depending on the amount of secretions produced.
1. Preoxygenate with 100% oxygen.
2. Aseptically prepare hands and wear sterile gloves.
3. Remove the inner cannula if present. Clean the inner lumen of the tracheostomy tube with sterile cotton buds +/- 0.05% chlorhexidine solution. Clean the outside of the tube with sterile swabs +/ chlorhexidine solution.
4. Humidify the airways with a humidifier for 3–5 minutes. This will help loosen secretions. If a humidifier is not available, small volumes (0.5–3ml) of sterile saline can be instilled into the tracheostomy tube instead; however, there is risk of introducing bacteria into the lungs.
5. Preoxygenate the patient with 100% oxygen for 1 minute.
6. Aseptically place a suction cannula attached to a suction unit. Most suction cannulas have a thumb port to control suctioning. Place the cannula down to the tracheal bifurcation without occluding the thumb port. Suction by occluding the thumb port, and rotating in a circular movement while gently withdrawing the cannula. Suctioning should not take greater than 10 seconds. Once completed, administer 100% oxygen again for 1 minute. If large amounts of secretions are produced, repeat the procedure.
7. If an inner cannula was present, replace the inner cannula with a new or sterile cannula. Clean the used cannula with 0.05% chlorhexidine, and keep bathed in a 0.05% chlorhexidine solution so the two tubes can be used alternatively. Before replacing the inner cannula, rinse with sterile saline or sterile water.
8. Tracheostomy tubes without a cannula should be changed every 24 hours. Preoxygenate the patient with 100% oxygen, keep the trachea open using the cranial and caudal stay sutures. Remove the old tube and replace with a new tube immediately.
Removal of Tracheostomy
If the upper airway disease is improving/resolved, and you think the patient can breathe through their oropharynx again, the tracheostomy tube may be removed. To test if this is possible, occlude the tracheostomy tube opening with a sterile gloved finger for several minutes. If the outer diameter of the tube is small enough, the patient should be able to breathe around the tracheostomy tube. If the tube is a snug fit, then replace with a smaller tube for the occlusion test. If there is a cuff, the cuff must be deflated. Once removed, the tracheostomy site is left open. Suturing the site can cause pneumomediastinum and subcutaneous emphysema. The wound should be cleaned regularly. When discharging the patient home, strict instructions should be given not to place a collar around the neck, no baths, and ensure there are no areas of water the patient may accidentally place their neck (e.g., large water bowls, ponds, etc.).
References are available upon request.