This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
[{'content': "Patients is not breathing after anaesthesia is due to \nSelect and explain. \nA. Prolonged anaesthesia, B. Neuro muscular blockage, C. Recurrent intubation leading cord's failure, D. All of the above", 'role': 'user'}, {'content': 'Answer: D \nExplanation: (All of the above) (513 - Lees 13th)* Hypoxaemia is best detected by a pulse oximeter or measurement of blood gases. Hypoxaemia is a late sign of hypoventilationApnoea during spinal and extra dural anaesthesiaCauses of apnoea during spinal and extradural analgesia include* Inadeguate medullary blood flow due to inadequate cardiac output - a serious situation demanding immediate cardio respiratory support* Total spinal analgesia with denervation of all the respiratory muscles true phrenic paralysis is uncommon because the motor roots are large* Accidental subdural injection : a small volume of solution may travel to an unexpectedly high level in this potential space* Toxic effects of the local analgesic drug* Injection of a opioid analgesic drug', 'role': 'assistant'}]