[Anaesthesiology] Neuromuscular blockade

It is often necessary to blockade neuromuscular signalling to induce muscular paralysis. 
There are two types of neuromuscular blockade (NMB) agents. 

 

Depolarising neuromuscular blocking agents

These act by competitively blocking the binding of ACh to its receptors, and in some cases, they also directly block the ionotropic activity of the ACh receptors

• Succinylcholine
• Decamethonium (rarely)

Non-depolarising neuromuscular blocking agents

These act by depolarizing the sarcolemma of the skeletal muscle fiber. This persistent depolarisation makes the muscle fiber resistant to further stimulation by ACh.

• Mivacurium  
• Atracurium 
• Cisatracurium
• Vecuronium  
• Rocuronium 
• Pancuronium

Indications

• Facilitating tracheal intubation. 
• Assisting orthopaedic surgeons in manipulating limbs. 

Reversal agents

• Acetylcholinesterase inhibitor

Adverse effects

• Anaesthesia may end before NMB. Therefore, it is necessary to remain with the patient until normal neuromuscular signalling has returned, so that the airway can be protected. 
• Suxamethonium and decamethonium are known causes of malignant hyperthermia.