College Answer

This appears to be a chronic problem, and there is probably not time to discuss possible/probable
futility of more active therapy. Key features of management should include:
•    clinical assessment to help establish the diagnosis (especially sensation, pattern of weakness
[eg. lower motor neurone, long tract signs etc])
•    reasonable  to  intubate/ventilate  (hopefully  after  a  full  clinical  examination  has  been performed)
•    drugs for intubation – such as the acute risk with suxamethonium, and the potential harm associated with the use of neuromuscular blockade
•    establishment of specific diagnosis (from disorders of muscle, neuromuscular junction, peripheral nerves, anterior horn cell disease, cord lesions and central lesions)
•    collaboration with neurologists,
•    relevant investigations (eg. EMG, LP, CT, MRI etc)
•    general supportive care, including consideration of early tracheostomy.

Common problems related to lack of relevant detailed knowledge.

Discussion

This question brings about another round of differential diagnosis generation, for the question "what is causing this whole-body weakness". The assessment of the critically ill patient with weakness is well discussed elsewhere.

Thus:

• First, one would take a detailed history, and perform a focused clinical examination, with attention paid to airway and breathing.
• If these are stable (i.e. intubation is not imminent) then a complete neurological examination can be performed.
• Then, the airway control can be definitively established. The patient needs intubation before she aspirates.
• Muscle relaxant choice would rest with some sort of non-depolarising agent
• Once intubated, the ventilation can be addressed, and normoxia established.
• Now, aspiration pneumonia can be investigated with a chest Xray, which would also confirm line placement and ETT position.
• Once the ABCs have been controlled, investigation of the underlying disrder can be approached
• Potential causes and their investigations include
  • Central cerebral lesions - CT brain
  • Brainstem lesions - CT/MRI
  • Spinal cord lesions - MRI
  • Infectious and autoimmune CNS pathology - LP
  • Peripheral nerves - nerve conduction studies
  • NMJ diseases - electromyography (EMG) and acetylcholine receptor antibodies
  • Myopathy - raised CK and muscle biopsy
  • Critical illness polyneuropathy - clinical diagnosis
  • Steroid myopathy - history, and its a clinical diagnosis
  • Electrolyte derangement - electrolyte levels
• Collaboration with neurologists is essential, because you will be discharging this patient into their care
• A tracheostomy needs to be thought about if the course of ventilation is expected to be prolonged.