McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 2 8 Neuromuscular junction blocking agents

CHAPTER SUMMARY ■■ The nerves communicate with muscles at a point called the neuromuscular junction (NMJ), using acetylcholine (ACh) as the neurotransmitter. ■■ NMJ blockers interfere with muscle function. The two groups of NMJ blockers are non-depolarising and depolarising agents. ■■ The non-depolarising NMJs include those agents that act as antagonists to ACh at the NMJ and prevent depolarisation of muscle cells. The depolarising NMJs act as an ACh agonist at the junction, causing stimulation of the muscle cell and then preventing it from repolarising. ■■ NMJ blockers are primarily used as adjuncts to general anaesthesia, to facilitate endotracheal intubation, to facilitate mechanical ventilation and to prevent injury during electroconvulsive therapy. ■■ Adverse effects of NMJ blockers, such as prolonged paralysis, inability to breathe, weakness, muscle pain and soreness, and effects of immobility are related to muscle function blocking. ■■ Care of people receiving NMJ blockers must include: support and reassurance because communication is decreased with paralysis; vigilant maintenance of airways and respiration; prevention of skin breakdown; and monitoring for return of function. Implementation Provide comfort and safety measures: positioning, skin care, temperature control, pain medication as needed, maintain airway, ventilate person, have antidotes on standby. Provide support and reassurance to deal with paralysis and inability to communicate. Provide teaching about procedure being performed and what to expect. Assist with life support as needed. Evaluation Evaluate drug effects: muscle paralysis. Monitor for adverse effects: cardiovascular effects (tachycardia, hypotension, respiratory distress, increased respiratory secretions), GI effects (constipation, nausea), skin breakdown, anxiety, fear. Monitor for drug–drug interactions as indicated. Evaluate the effectiveness of the teaching program and comfort and safety measures. Constantly monitor vital signs and watch for return of normal muscular function. TEACHING FOR S.N. • Before the surgery is performed, you will be given a drug to paralyse your muscles called a neuromuscular

Knowing your strengths and weaknesses helps you to study more effectively. Take a PrepU Practice Quiz to find out how you measure up! ONLINE RESOURCES An extensive range of additional resources to enhance teaching and learning and to facilitate understanding of this chapter may be found online at the text’s accompanying website, located on thePoint at http://thepoint.lww.com. These include Watch and Learn videos, Concepts in Action animations, journal articles, review questions, case studies, discussion topics and quizzes. Healthcare providers and students may want to consult the following Internet sources: http://allaboutanaesthesia.com.au Information about anaesthesia and anaesthetics. www.anzca.edu.au Home page of the Australian and New Zealand College of Anaesthetists. www.spanza.org.au Home page of the Society for Paediatric Anaesthesia in New Zealand and Australia. WEB LINKS blocking agent. It is important that your muscles do not move at this time because it could interfere with the procedure. • Common effects of these drugs include complete paralysis: • You will not be able to move or to speak while you are receiving this drug. • You will not be able to breathe on your own, and you will receive assistance in breathing. • This drug may not affect your level of consciousness, and it can be very frightening to be unable to communicate with anyone around you. Someone will be with you, will try to anticipate your needs, and will explain what is going on at all times. • This drug may have no effect on your pain perception. Every effort will be made to make sure that you do not experience pain. • You will be receiving suxamethonium; with this drug, you may experience back and throat pain related to muscle contractions that occur. You will be able to take aspirin to relieve this discomfort. • Recovery of your muscle function may take 2 to 3 hours and someone will be nearby at all times until you have recovered from the paralysis.