SPECIAL MEDICAL EMERGENCY REQUIREMENTS
of patients with Mucopolysaccharidosis VI (MPS VI) and Morquio A (MPS IVA)
STABILISE THE NECK IMMEDIATELY TO AVOID CERVICAL CORD INJURY
- MPS VI and Morquio A patients are at significant risk or cervical cord injury that may result in paralysis and sudden, premature death.
- They may experience atlantoaxial instability,1,2,3 commonly associated with cervical cord compression and myelopathy.
- Use manual in-line stabilization to prevent cervical spine injury.5
- Limit the degree flexion/extension because of the possible laxity of ligaments (with or without odontoid dysplasia) and cervical stenosis.
- Intubation:Intubation: Maintain the patient in a neutral position during intubation since the “sniff” position may not be possible. Use fiberoptic intubation or video laryngoscopy.5
- Maintain rest of spinal column in neutral position as compression may occur in other regions.
- Neurophysiological monitoring is recommended for all patients undergoing prolonged (more than 30 minute) procedures or all procedures involving spine or manipulation o head (oral surgery, etc) surgeries.
EMERGENCY TRACHEOSTOMY MAY BE NECESSARY
CONTACT AN OTOLARYNGOLOGIST(ENT)
- Respiratory failure and airway-related emergencies are a common cause of morbidity in MPS patients,6 especially during surgical interventions.7 Critical decreases in oxygen saturation may occur suddenly.
- In an airway anaesthesia emergency, there may be less than 3–5 minutes to perorm an emergency tracheostomyspan> in MPS patients before permanent brain damage occurs.
- ANY sedative can cause respiratory complications, severe hypoxaemia, and consequently neurological impairment.5
- See video o airway obstructions: click here
- Airway obstruction:
- MPS patients may have obstructive sleep apnoea (OSA), increasing the risk of airway emergencies as well as chronic hypoxaemia.
- Airway obstructions (see picture) may cause difficulties with mask ventilation and intubation.
- TM joint contracture with diculty opening the mouth, and accumulation of glycosaminoglycans (GAGs) in the tongue, oral pharynx, and larynx can impede access to upper airway and identification of the glottis. This may resultin negative pressure pulmonary oedema, or an inability to ventilate/intubate5 or visualize the airway.7,8
- Serious complications may occur during extubation, including pulmonary oedema and the need for re-intubation or emergency tracheostomy.
- Have an otolaryngologist (ENT), preferably with MPS experience, readily available during any surgical procedure on MPS patients due to the high potential for an emergency tracheostomy.5
- Ensure the ENT is aware that perorming an emergency tracheostomy is more dicult, has a higher risk and will take longer for a patient with MPS because of the shorter neck, thickened soft tissue, and the depth of the trachea.5
- Be prepared for alternative methods of intubation (e.g. fiberoptic intubation) if mask induction followed by oral tracheal intubation is unsuccessful.5
- An oral anxiolytic may reduce anxiety and improve ability for fiberoptic intubation – but if the patient falls asleep, he or she may desaturate to dangerous levels due to upper airway obstruction.
- Have the pre-op nurse closely monitor oxygen saturation and call the anaesthesia team immediately if changes in oxygen saturation occur.
- Provide supplemental O2 during intubation due to the potential for diffculty in ventilation and oxygenation.7
- Consider use of nitrous oxide to assist in placement of an intravenous catheter followed by induction with midazolam or fentanyl (reversed by flumazenil and naloxone, if required).5
- Consider placing the patient in lateral position during induction phase if this improves the patient’s airway.
- Use fiberoptic bronchoscopy for tracheal induction if patient has a diffcult airway.5
- Use of a laryngeal mask airway (LMA) or nasal airway has been found to improve ventilation during bronchoscopy.5
- Consider inserting a J-tipped guide-wire through the suction channel of the bronchoscope into the trachea, remove the bronchoscope and insert a ureteral dilator or airway exchange catheter over the wire, then advancing the endotracheal tube (ETT) over this to help guide it into the trachea.9
- Avoid use of muscle relaxants until endotracheal intubation is achieved.5
- Use an ETT that is 2–3 times smaller than expected based on age.10
- In order to increase oxygen delivery to the patient during fiberoptic bronchoscopy, consider advancing a short ETT into the contralateral nares in order to provide continuous O2 into hypopharynx. Also, attaching O2 to the suction port of the bronchoscope and intermittently inject O2 from tip of fibre.
- Ensure full reversal of the muscle relaxant and place a nasopharyngeal airway prior to extubation.5
- Perform extubation in an area with access to the full medical personnel required should the patient need
immediate re-intubation or an emergency tracheostomy.5
DO NOT EXTUBATE
ENSURE SUFFICIENT SPACE IN THE
NOSE OR MOUTH FOR PASSAGE OF AIR.
- Difficult intubations may result in injury to the glottis, stridor, inection or airway collapse.
- Potential for chronic hypoxemia due to obstructive sleep apnoea (OSA).
- Once MPS patients are extubated, re-intubation may not be possible, creating a potential emergency.
- See video for anaesthesia techniques: click here
- If injury to the glottis has occurred: consider delaying extubation.
- Do not extubate until the airway is confirmed to be clear.
- Always have an experienced otolaryngologist (ENT) or paediatric surgeon in the room during all surgical procedures on MPS patients due to the high potential for an emergency tracheostomy.
- Significant cardiac manifestations are reported for MPS patients.6,1
- Cardiac valve disease is the most commonly reported cardiac manifestation in MPS patients,6,11 increasing the risk of mortality during surgical procedures.5
- Irreversible ischemia and cardiac arrest due to hypotension may occur.
- See video of cardiac monitoring: click here
- Continuously monitor MPS patients with EKG to identiy conduction abnormalities and signs o myocardial ischemia.
- Perform an echocardiogram to identify cardiac valve regurgitation or stenosis as well as decreased function
- Monitor blood pressure using intra-arterial cannulae if surgery is lengthy or high risk.5