SPECIAL MEDICAL EMERGENCY REQUIREMENTS

HIGH RISK ANAESTHESIA (both intubation and extubation)

RISKS:

• Respiratory failure and airway–related emergencies are a common cause of morbidity in MPS patients,¹ especially during surgical interventions.⁶ Critical decreases in oxygen saturation may occur suddenly¹
• In an airway anaesthesia emergency, there may be less than 3–5 minutes to perform an emergency tracheostomy before permanent brain damage occurs⁷
• ANY sedative can cause respiratory complications, severe hypoxaemia, and, consequently, neurological impairment¹
• Airway obstruction:
  • MPS patients may have obstructive sleep apnoea (OSA), increasing the risk of airway emergencies and chronic hypoxaemia⁸
  • Airway obstructions (see video) may cause diffculties with mask ventilation and intubation¹
  • Temporomandibular joint contracture with diffculty opening the mouth, and accumulation of glycosaminoglycans (GAGs) in the tongue, oral pharynx, and larynx can impede access to the upper airway and identification of the glottis¹. This may result in negative pressure pulmonary oedema, or an inability to ventilate/intubate¹ or visualise the airway⁹
  • Serious complications may occur during extubation, including pulmonary oedema, and the need for re–intubation or emergency tracheostomy¹

RECOMMENDATIONS:

• 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 tracheostomy¹
• Ensure the ENT is aware that performing an emergency tracheostomy is more diffcult, has a higher risk and will take longer for a patient with MPS because of their shorter neck, thickened soft tissue, and the depth of their trachea¹
• Be prepared for alternative methods of intubation (e.g. fibre–optic intubation) if mask induction followed by oral tracheal intubation is unsuccessful¹
• An oral anxiolytic may reduce anxiety and increase the potential for successful fibre–optic intubation – but, if the patient falls asleep, he or she may desaturate to dangerous levels due to upper airway obstruction¹
• Have the pre–op nurse closely monitor oxygen saturation and call the anaesthesia team immediately if changes in oxygen saturation occur¹
• Provide supplemental O₂ during intubation due to the potential for diffculty in ventilation and oxygenation¹
• 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)¹
• Consider placing the patient in the lateral position during induction phase if this improves their airway¹
• Use fibre–optic bronchoscopy for tracheal induction if patient has a diffcult airway⁵
• Use of a laryngeal mask airway (LMA) or nasal airway has been found to improve ventilation during bronchoscopy¹
• 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 trachea⁵
• Avoid use of muscle relaxants until endotracheal intubation is achieved¹
• Use an ETT that is 2–3 times smaller than expected based on age¹
• In order to increase oxygen delivery to the patient during fibre–optic bronchoscopy, consider advancing a short ETT into the contralateral nares to provide continuous O₂ into hypopharynx. Also, attach O₂ to the suction port of the bronchoscope and intermittently inject O₂ from tip of fibre¹⁰
• Ensure full reversal of the muscle relaxant and place a nasopharyngeal airway prior to extubation¹
• Perform extubation in an area with access to the full medical personnel required should the patient need immediate re–intubation or an emergency tracheostomy¹