Page 95 - WSAVA2017
P. 95

D. McBride1
1Royal Veterinary College, Queen Mother Hospital for Animals, London, United Kingdom
Royal Veterinary College, Hawkshead Lane, North Mymms, United Kingdom
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.
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