Page 687 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

662 CHAPTER 3

VetBooks.ir to be taken over diagnosis. Generally, upper airway Management
The number one priority in any circulatory emer-
obstruction results in inspiratory dyspnoea, while
lower airway is expiratory dyspnoea. Some horses
nasal intubation in some cases. Notably after gen-
will present with collapse. Non-cardiogenic pulmo- gency is ‘A’ – airway. An airway can be provided by
nary oedema is a common sequela of upper airway eral anaesthesia with respiratory distress, a naso-
obstruction in the horse, so blood-stained frothy tracheal tube can usually be passed. A 16–24-mm
nasal discharge is commonly involved. endotracheal tube or large bore stomach tube is
ideal for this purpose. In many cases it is difficult
Differential diagnosis or impossible to pass a tube via the nostrils. It is
Obstructive lower airway disease is the most impor- important not to watch the horse die while trying
tant differential diagnosis. Passage of a nasotracheal nasal intubation. Emergency tracheotomy is often
tube (see below) can be useful to establish if there is necessary. Local anaesthetic should be instilled
an upper or lower airway obstruction. into the midline of the cranial third of the ven-
tral neck. In a severe emergency there is not time
Diagnosis to instil local anaesthetic and in such severe situ-
Endoscopic examination is diagnostic but, in many ations there is minimal reaction from the horse
cases, there is insufficient time for diagnosis – the during surgery. Aseptic preparation is ideal but is
veterinary surgeon may not have an endoscope avail- optional under severe pressure. A linear 10–15 cm
able or examination may precipitate an episode of incision is made through the skin. The incision is
collapse. continued through the sternothyrohyoid muscle
to the ventral surface of the trachea. An inci-
sion is then made transversely between two tra-
3.110 cheal rings. Once into the airway a finger can be
inserted to separate the tracheal rings far enough
to allow enough air passage to sustain life. A tube
should then be passed to allow the airway to be
maintained. A cut off portion of stomach tube is
effective, as is the cut off hollow handle of a typi-
cal 5 litre container. The tube should then be tied
in place around the neck.

Prognosis
Once an airway is established, the prognosis is
dependent on diagnosis of the underlying condi-
tion. Horses with severe swelling from snakebites
or stings have an excellent prognosis (Fig. 3.110).
Once the swelling has subsided the tube is
removed. Second intention healing is almost
invariably uneventful over the next few weeks
Fig. 3.110 Horse (Fig. 3.111). Horses with surgical conditions of
with an adder bite the upper airway can be treated appropriately,
on the lip and severe with the corresponding prognosis. Horses with
facial swelling. Such expansile conditions of the upper airway, such as
horses should be tumours or PEH have a poor prognosis. These
monitored closely horses can be managed with temporary or perma-
for signs of airway nent tracheotomy tubes for many months or even
occlusion. years (Fig. 3.112).