Plus-Hex CLINICAL
Further medications that are often given before BOAS surgery are gastroprotectants and antiemetics. Maropitant( Cerenia 10 mg / ml, Zoetis, 1 mg / kg IV or subcutaneously( SC)) is often given to prevent vomiting, although it will not prevent regurgitation. It should be given 60 min before surgery [ 6 ]. Metoclopramide( Emeprid 5 mg / ml, Ceva Animal Health, 1 – 2 mg / kg over 24 hours) is also used, with mixed reports as to whether it is effective in this scenario [ 12 ].
Omeprazole( Teva, 1 mg / kg) is often given orally 3 – 5 days ahead of surgery [ 9 ], and the owner should be made aware that this is to help prevent regurgitation during surgery. The patient can also be given omeprazole( Sandoz, 40 mg vial diluted to 0.4 mg / ml, dose: 1 mg / kg) by IV injection over a 30 min period before surgery, or by IM injection 90 min before intubation using a longacting formulation( Omeprazole Injection, Bova Specials UK, 100 mg / ml, dose: 4 mg / kg) [ 13 ]. This option should be considered if owners express concern about giving oral medication or it is causing more stress than is necessary.
Eye lubricant should also be applied regularly during the perianaesthetic period because exophthalmos is common in dogs with BOAS, and it will help prevent eye ulcers from forming [ 7 ]. If the equipment is available, non-sterile suction should be on hand to remove any regurgitation, should it occur. At all stages, the patient should remain in sternal recumbency, where possible, to prevent atelectasis and reduction of O 2 perfusion.
The patient should be monitored using pulse oximetry to measure oxygen saturation( SpO 2
), capnography, blood pressure and temperature monitoring [ 9 ], and electrocardiography. However, the VN will have to consider the access required by the VS to and around the head of the patient. Where possible, monitoring equipment such as temperature probes and pulse oximetry should be placed elsewhere on the patient ' s body. Ideally, invasive blood pressure( IBP) monitoring with a multiparameter monitor capable of IBP measurement and a transducer should be used, as this gives real-time measurement of blood pressure by measuring arterial blood pressure via an arterial catheter.
The ET tube and circuit should be well secured to ensure they cannot accidentally be dislodged while working on the patient. The VN should also prepare sterilised tongue depressors, cotton buds or sponges on sticks so the VS can apply pressure to incisions in and around the soft palate. An iodine-based surgical skin preparation( 1:20 dilution) should also be prepared if rhinoplasty is to occur. Chlorhexidine would be contraindicated in this scenario as it should not be used on the mucous membranes.
The patient ' s head should be propped up, with rolledup towels placed under the neck or wedges to provide support. The maxilla will need to be held open; often, cohesive bandage( vet wrap) is placed behind the canine teeth and fastened either to a square frame attached to the surgical table or to drip stands placed either side of the patient. A mouth gag can also be used to provide the VS a clear view of the oral cavity. The mandible will also need to be kept open, and conforming bandage, e. g. K-Band, or tape can be used for this purpose [ 14 ].
Peri-anaesthesia concerns
Vagal response causing bradycardia and hypotension
A heightened vagal response can occur when manipulating the patient ' s trachea. Care should be taken when intubating, by using a laryngoscope to clearly visualise the airway and intubate as quickly as possible, so as not to overstimulate the trachea. Monitoring equipment such as temperature probes should be placed elsewhere on the patient ' s body to lower the chances of creating this response [ 6 ]. These patients are also at risk of sinus arrest on inspiration due to higher vagal tone [ 11 ]; however, as sinus arrest can be common in brachycephalic dogs, treatment with atropine( Hameln Pharma Ltd, 0.01 – 0.04 mg / kg IM or IV) is administered only when the sinus arrest causes decreased cardiac output. Similarly, when adjusting the patient on the table, sudden changes in position can cause a vagal response, and so these adjustments should be made slowly by the nursing team [ 9 ].
High end-tidal carbon dioxide( ETCO 2
) and hypercapnia leading to rebreathing and hypoxia
This can occur as brachycephalic dogs tend to have a higher partial pressure of carbon dioxide( PaCO 2
) [ 9 ], which shows on a capnograph as a higher ETCO 2
, leading to hyperventilation as the patient tries to remove the excess carbon dioxide( CO 2
). If this becomes a consistent issue while the patient is under anaesthetic, increasing O 2 delivery, placing the patient on a ventilator or applying intermittent-positive pressure ventilation( IPPV) can assist. A‘ shark’ s fin’ trace( an upward-sloping waveform that looks like a shark ' s fin) on the capnograph indicates airway obstruction; the patient may have mucus covering the end of the ET tube [ 9 ] or a kink in the tube obstructing the flow of air into the airway.
Hypothermia
Hypothermia, leading to prolonged recovery time [ 6 ] and increased O 2 requirement in a patient with an already inflamed and irritated airway, can be a concern. Ideally, active heating with either a forced warm air blanket, such as a Bair Hugger, or heat mat can help to prevent heat loss during surgery. The patient ' s temperature should be carefully monitored and active heating should be stopped once it is 36.5 – 37 ° C [ 3 ]. This will prevent overheating, which would cause excessive panting in recovery, leading to a higher O 2 requirement and more stress on the inflamed airway.
Volume 41( 3) • June 2026
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