Brachycephalic Obstructive Airway Syndrome Surgery (BOAS)  

BOAS patients, by the very nature of the condition, will be a higher anaesthetic risk category than other patients. Ensuring that they are stable before surgery is therefore high on our list of considerations. It is good to discuss medication protocols with your surgeon before starting. Be mindful of possible side effects of various medications that can be given. Opioids such as methadone can cause hypersalivation and panting, which could become detrimental to a respiratory compromised patient. Some medications such as midazolam can cause excitement which would also not be suitable for these types of patients. The surgery itself shouldn't be overly painful for most patients, so some surgeons may opt to avoid any potent opioids for premedication and instead utilise paracetamol and NSAIDs for analgesia instead. Others may use full opioids and supplement with an antiemetic such as maropitant to counteract any nausea and regurgitation that could occur. Either way, try to familiarise yourself with the medications prior to surgery to avoid any unwanted surprises!

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I'd recommend having the patient preoxygenated for as long as possible before and after premedication. If they will tolerate nasal prongs, these can work well on brachycephalic patients. The majority of BOAS patients will also have prominent eyes due to their face shapes, so remember to lubricate their eyes frequently at all peri-operative stages to reduce corneal ulceration risks.

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Once premedicated, do not leave the patient unattended and ideally maintain them in sternal recumbancy with their head elevated and forward to maximise breathing abilities. Ensure that you have emergency airway kit to hand once premedicated as well in case the patient becomes compromised and requires assistance. I will keep this kit with the patient until they are discharged, just in case of an emergency.

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Once intubated and under general anaesthesia, maintain the patient in sternal recumbancy and use foam wedges to keep the head elevated and forward. Suction may be needed at intubation as BOAS patients often suffer with gastrointestinal conditions including reflux, which can pose a higher risk at this stage. If the patient is overweight, it can be beneficial to angle the table or the patient with the chest and head slightly higher than the abdomen, to reduce pressure on the lungs. 

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The surgery can then proceed.

 

Monitor capnography carefully throughout, as well as pulse oximetry, as these can give valuable information on respiration and oxygen saturation. Note: often brachycephalic patients will present as hypercapnic (normal range for ETC02 is 35-45mmHg), so don't be alarmed if this is high when first intubated.

 

During the surgery, ensure that the ET tube doesn't become dislodged or damaged (especially if using a surgical laser). It can sometimes be useful to get the surgeon to place a swab over the tube if they are using the laser near to it, to keep it protected. 

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Bleeding can be a factor during these surgeries, so I will make sure to always have a couple of adrenaline soaked swabs or cotton buds which can be held over any bleeding to improve vasoconstriction at these sites. 

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Due to the location of the surgery, it is obviously difficult to assess the palpebral reflex and eye positions of the patient. Make sure to communicate with your surgeon and ask them to report positions and reflexes back to you if they are able to. 

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Once the surgery is complete, I will often get the surgeon to place a couple of frozen throat packs at the back of the mouth for a few minutes to aid with reducing inflammation before switching off the anaesthetic agent (assuming the patient is stable and hasn't been anaesthetised for an extended amount of time). ENSURE THAT THESE ARE REMOVED PRIOR TO RECOVERY.

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When the patient is recovering, make sure to leave the ET tube in place for as long as possible. Often BOAS patients will tolerate an ET tube incredibly well once awake and I will usually wait until they are either chewing on the tube or walking around before removing it. Once the tube is removed, monitor the patient very closely for any signs of respiratory distress. Sometimes it may be necessary to provide additional sedation if they recovery excitably or are barking excessively. It can be useful to keep pulse oximetry on the patient whilst recovering also and supplemental oxygen can be given if they are struggling to keep saturation numbers high.

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Keep the patient's emergency airway kit with them and remember to lubricate the eyes freqently.

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If they will tolerate it, use of a nebuliser with adrenaline (I use 1mg adrenaline diluted in 5ml of sterile saline solution) for 10 minutes q6h, works well at reducing inflammation in the upper respirratory tract.