Summary

In study session III you have learnt

• Neuromuscular blocking drugs interrupt transmission of nerve impulses at the neuromuscular junction (NMJ) and thereby produce paralysis of skeletal muscles. The principal clinical uses of NMBDs are to produce skeletal muscle relaxation for facilitation of tracheal intubation and to provide optimal surgical working conditions
• Depolarizing muscle relaxants (Suxamethonium) mimics the action of ach and produces a sustained depolarization of the postjunctional membrane. Non depolarizing muscle relaxants act by occupying the receptor site the muscle relaxant molecules prevent acetylcholine from attaching.
• Dual block occasionally follows a repeated dose of suxamethonium. A single dose causes a pure depolarizing block. This is termed a phase I block. A repeated dose causes the same drug to act differently and occasionally produce a nondepolarizing block.
• Mixed block may follow the simultaneous injection of depolarizer and nondepolarizer. The receptors may manifest both types of blocks at the same time. It is good to be aware of dual and mixed blocks. The important point is to ventilate these patients until they start breathing spontaneously again.
• Anticholinesterase drugs (neostigmine, pyridostigmine) are typically administered during the time when spontaneous recovery from the neuromuscular blockade.
• Anticholinergics are a class of medications that inhibit parasympathetic nerve impulses (blocks the neurotransmitter acetylcholine) by selectively blocking the binding of the neurotransmitter acetylcholine to its receptor in nerve cells. Atropine, scopolamine, and glycopyrrolate are the three most common antimuscarinic drugs used in anesthetic practice.
• The central anticholinergic syndrome refers to central nervous system changes that range from unconsciousness to hallucinations. Agitation and delirium are not unusual in elderly patients. Other systemic manifestations include dry mouth, tachycardia, atropine flush, atropine fever, and impaired vision.