& Management / Disease
Investigation & Management / Techniques:
- Induce anaesthesia in the rabbit (usually with injectable agents,
sometimes with injectable and volatile agents in combination. (J60.13.w1)
- Ensure the rabbit is adequately anaesthetised. (J34.23.w1)
- Wait until jaw relaxation has developed before intubating. (J15.30.w2)
- Give the rabbit 100% oxygen for at least two minutes before
attempting intubation to reduce the risk of hypoxia developing; (B601.16.w16)
for a few minutes. (J15.30.w2)
- Consider spraying the larynx with lidocaine
spray to reduce the risk
of laryngospasm. (J15.20.w2,
- Note: if intubation fails, try a smaller endotracheal tube.
If two or three attempts fail, stop trying to intubate, as continuing
risks development of laryngeal trauma (oedema, haemorrhage) and laryngeal
spasm, which can lead to respiratory obstruction and may therefore be
- Pre-measure the tube to the level of the larynx.
- Place the rabbit in sternal recumbency and hyper-extend the neck,
bringing the glottis in line with the oropharyx.
- Lift so the rabbit's front legs are only just on the table. (J15.20.w2)
- Gently pull the tongue out to one side. (J83.28.w1)
- Insert the endotracheal tube into the mouth to the pre-measured point.
- Listen at the connector end of the tube.
- Or with a clear endotracheal tube, look for condensation appearing in the
- When breath sounds are loudest (when the tip of the tube is at the
glottis during inspiration), gently advance the tube.
OR when strong fogging occurs in a clear tube, indicating
correct positioning at the larynx. (J83.28.w1)
- Often increased breathing sounds and commonly a slight cough are
noted when the tube enters the larynx. (J15.20.w2)
- Condensation clears as inspiration starts; this is the time to
advance the tube. (J213.10.w2)
- If the sounds of breathing are no longer audible (or condensation is
no longer appearing and disappearing), the tube has failed to enter the larynx;
withdraw and try again. (J15.20.w2,
- Hold a bit of fur at the end of the tube and check for movement of
the fur in association with inspiration/expiration.
- It is easy to traumatise the glottis with this method. (J60.13.w1)
- Repeated attempts at blind intubation are not recommended. (J60.13.w1)
(B545.8.w8, J15.20.w2, J15.30.w2,
- Place the rabbit in sternal recumbency and hyper-extend the neck,
bringing the larynx in line with the oropharyx.
- Hold the rabbit's mouth wide open.
- Either use bandage materials or a dental gag as retractors.
- Or have an assistant hold the skull in a hyperextended position,
while the operator pulls the mandible ventrally.
- Gently pull the tip of the tongue out of the mouth.
- Take care not to damage this on the lower incisors, which have
sharp occlusal surfaces.
- Use a small laryngoscope, otoscope or endoscope to allow
visualisation of the glottis.
- With a laryngoscope
- Use a laryngoscope with a size 0 or size 1 Wisconsin blade.
- Use the blade to keep the mouth open and (tip of the blade)
depress the fleshy torus at the back of the tongue.
- Note: at this point, often the soft palate is ventral to
- With the tip of the endotracheal tube, elevate the soft palate,
revealing the glottis.
- Observe the glottis.
- During inspiration, insert the endotracheal tube through the
larynx into the trachea.
- Do not force the tube into the trachea.
- Alternatively in small rabbits: initially insert a
smaller-diameter tube e.g. a 5 or 9 French polypropylene urinary
catheter, then remove the laryngoscope and advance the
endotracheal tube over the catheter into the larynx. Withdraw the
- With an otoscope with a closed cone
- Initially pass a stylet (e.g. 3-5 Fr urinary catheter) through
the otoscope and through the larynx into the trachea.
- Pass the endotracheal tube over the stylet.
- Remove the connector from the endotracheal tube.
- Remove the otoscope.
- Reattach the connector.
- Or pass the stylet, remove the otoscope, then pass the
endotracheal tube over the stylet.
- With an otoscope, rabbit in dorsal recumbency:
- Grasp the tongue and gently pull it forwards and to one side.
- Introduce the otoscope into the mouth until the larynx is
- Pass an introducer (e.g. cat catheter) through the otoscope,
through the larynx and into the trachea.
- If the epiglottis is visible rather than the larynx, use the tip
of the otoscope, or the introducer, to gently push this out of the
- Keeping the introducer in position, remove the otoscope.
- Lubricate the tip of an endotracheal tube with gel such as
- Thread the endotracheal tube (2.5 - 3.0 mm for rabbits 1 - 3 kg)
over the introducer and advance this through the larynx into the
- If there is some resistance (common) as the endotracheal
tube reaches the larynx, gentle rotation while advancing the
tube may assist.
- Once the endotracheal tube is securely into the trachea,
withdraw the introducer.
- Tie the endotracheal tube into position.
- With a rigid endoscope
- Insert a rigid endoscope into the lumen of a (2.5 - 4.5 mm
internal diameter) endotracheal tube; only a few mm of the tube
should extend beyond the end of the endoscope.
- Place the rabbit supine with its head extended over the edge of
the table and resting on an assistant's hand
- Insert the endoscope and tube into the rabbit's mouth.
- Have the assistant pull the rabbit's tongue slightly outwards.
- Use direct visualisation to advance through the glottis and
vocal cords (as they open during inspiration) and into
- Advance the endotracheal tube over the end of the endoscope,
further into the trachea.
- Quickly withdraw the endoscope.
- Attach the endotracheal tube to the anaesthetic
- With a semi-rigid endoscope (J513.7.w1,
- Select an endotracheal tube, 2.0 - 3.5 mm internal diameter, Cole or
- Trim the tube at the adaptor end if it is longer than 6 inches in
- Insert a semi-flexible endoscope into the tube from its adapter end.
- Focuscope semi-flexible fibreoptic endoscope with
portable handheld light source. (J513.7.w1)
- Stop with the endoscope still 1-2 mm inside the tube.
- This maximises the field of view while protecting the patient's
tissues from the end of the endoscope and avoiding saliva and
mucus collecting in the tip of the tube.
- Apply a small amount of lidocaine lubricant jelly or lidocaine
injectable solution to the larynx or the tip of the endotracheal tube
- Look directly through the scope using the handheld battery-powered
- Or visualise via a video monitor if preferred.
- Anaesthetise the rabbit.
- Consider giving atropine or glycopyrrolate to decrease salivary
- Place the rabbit in lateral recumbency.
- Advance the tip of the combined endotracheal tube and endoscope over
the base of the tongue until the tip of the epiglottis is visible
through the soft palate.
- Advance the scope gently dorso-caudally, to lift the soft palate and
allow the epiglottis to fall forwards.
- Withdraw the endoscope about 1 cm so the tip rests on the epiglottis
and the glottis is visualised.
- Advance the endoscope and ET tube into the laryngeal opening.
- On inspiration, advance the endoscope and ET tube into the trachea.
- Correct positioning is confirmed by the visualisation of the
tracheal rings. (J513.7.w1)
- Withdraw the endoscope. (J513.7.w1)
- Confirm the position of the endotracheal tube
- Auscultate both lung fields to check the tube has not passed the
bifurcation and entered one of the bronchi. (J513.7.w1)
- Note: the rabbit will not necessarily cough when the
endotracheal tube enters the trachea. (J60.13.w1)
- Hold hairs at the connector end and observe these for movement
as the rabbit breathes. (J60.13.w1)
- Check that thoracic movement results if positive pressure
ventilation is produced using the anaesthetic circuit. (J60.13.w1)
- Secure the endotracheal tube with open-weave bandage tied around the connector
and then around the back of the rabbit's head. (J60.13.w1)
|Appropriate Use (?)
Reasons to intubate include:
- Enables provision of supplemental oxygen.
- Protects the lower respiratory tract from foreign material,
including fluids (if the tube is tight-fitting or shouldered) during
- Allows well-controlled anaesthetic gas provision together with
minimal atmospheric contamination.
- Enables use of intermittent positive-pressure ventilation (IPPV) if
required to assist lung perfusion and if needed during a respiratory
- Nasotracheal intubation is useful during oral surgery to deliver oxygen without obstructing
access to the oral cavity. (B601.16.w16)
- Rabbits have a small tidal volume, about 4-6 mL/kg; small increases
in dead space within the anaesthetic system can significantly affect
respiratory efficiency. (J60.13.w1)
|Complications / Limitations / Risk
"The oropharyngeal anatomy of the rabbit, specifically the presence of large incisors, long and narrow dental arcade, the hump at the base of the tongue, and the acute angle between the mouth and the larynx, makes orotracheal intubation of rabbits technically difficult with a high failure
- Not appropriate for short anaesthetics where carrying out intubation
could unduly prolong the anaesthetic. (J60.13.w1)
- Usually not used for routine dentals, as the tube will reduce oral
- Repeated attempts at endotracheal intubation may cause traumatic
damage to the larynx (with resultant laryngeal oedema, haemorrhage, laryngospasm or
even laryngeal perforation), which can lead to respiratory obstruction
and may therefore be fatal. Additionally, repeated attempts at
intubation may prolong the required anaesthetic
- Attempt intubation only for a limited time (a few minutes). (J513.7.w1)
- Stop trying to intubate if there is any evidence of injury to
the larynx. (J513.7.w1)
- With blind intubation, there is a risk that food or caecotrophs held
unseen in the rabbit's mouth may be pushed into the trachea with the
endotracheal tube. (V.w125)
- Accidental extubation may occur. (J513.7.w1)
- If the tube is advanced too far it may pass from the trachea into
one of the two main bronchi, resulting in aeration of one lung only. (J513.7.w1)
- If the rabbit breaths air, rather than 100% oxygen, prior to
intubation, hypoxia may develop rapidly during the intubation
- This can be prevented by giving 100% oxygen for two minutes
prior to the start of intubation. (B601.16.w16)
|Equipment / Chemicals required and Suppliers
Endotracheal tubes, small, uncuffed, in a
variety of sizes. (J60.13.w1)
Note: usually, new tubes need to be shortened
so that when the connector is at the lips the end of the tube is in
the trachea. Keeping the tube short reduces dead space in the
anaesthetic system. (J60.13.w1)
Local anaesthetic to reduce laryngospasm.
Stylet to stiffen the endotracheal tube during
initial placement, if preferred. (J60.13.w1)
For direct visualisation
Over-the-top endotracheal intubation
Focuscope semi-flexible fibreoptic endoscope with
portable handheld light source. (J513.7.w1)
Endotracheal tubes, 2.0 - 3.5 mm internal diameter,
either Cole stepped wall or straight-walled. (J513.7.w1)
|Expertise level / Ease of Use
- This procedure should only be
carried out by an individual with appropriate clinical training and practical
- Intubation of rabbits needs practice. (J513.7.w1)
|Cost / Availability
- Inexpensive except when expensive endoscopes are used for
|Legal and Ethical Considerations
In some countries there may be
legislation restricting the use of this type of technique to licensed veterinarians. For
example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides,
subject to a number of exceptions, that only registered members of the Royal College of
Veterinary Surgeons may practice veterinary surgery." (See: LCofC1
- RCVS Guide to Professional Conduct 2000 - Treatment of
Animals by Non-Veterinary Surgeons).
||Debra Bourne MA VetMB PhD
||Molly Varga BVetMed DZooMed MRCVS