McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 2 7 General and local anaesthetic agents

CHAPTER SUMMARY ■■ General anaesthetics result in analgesia, amnesia and unconsciousness; they also block muscle reflexes that could interfere with a surgical procedure or put the person at risk for harm. ■■ The use of general anaesthetics involves a widespread CNS depression that could be harmful, especially in people with underlying CNS, cardiovascular or respiratory diseases. ■■ Anaesthesia proceeds through four predictable stages from loss of sensation to total CNS depression and death. ■■ Induction of anaesthesia is the period of time from the beginning of anaesthesia administration until the person reaches surgical anaesthesia. ■■ Balanced anaesthesia involves giving a variety of drugs, including anticholinergics, rapid intravenous anaesthetics, inhaled anaesthetics, NMJ blockers and opioids. ■■ People receiving general anaesthetics should be monitored for any adverse effects; they need reassurance and safety measures until the recovery of sensation, mobility and the ability to communicate. ■■ Local anaesthetics block the depolarisation of nerve membranes, preventing the transmission of pain sensations and motor stimuli. Focus physical examination on the following: CV: blood pressure, pulse, peripheral perfusion, ECG CNS: orientation, affect, reflexes, vision Skin: colour, lesions, texture, sweating Respiratory: respiration, adventitious sounds Laboratory tests: liver function tests, plasma esterases Implementation Provide comfort and safety measures: positioning, skin care, side rails, pain medication as needed, maintain airway, antidotes on standby. Provide support and reassurance to deal with loss of sensation and mobility. Provide teaching about procedure being performed and what to expect. Provide life support as needed. Evaluation Evaluate drug effects: loss of sensation, loss of movement. Monitor for adverse effects: cardiovascular effects (blood pressure changes, arrhythmias), respiratory depression, GI upset, CNS alterations, skin breakdown, anxiety and fear. Monitor for drug–drug interactions as indicated for each drug.

■■ Local anaesthetics are administered to deliver the drug directly to the desired area and to prevent systemic absorption, which could lead to serious interruption of nerve impulses and response. ■■ Ester-type local anaesthetics are immediately destroyed by plasma esterases. Amide local anaesthetics are destroyed in the liver and have a greater risk of accumulation and systemic toxicity. ■■ Care of people receiving general or local anaesthetics should include safety precautions to prevent injury and skin breakdown; support and reassurance to deal with the loss of sensation and mobility; and teaching regarding what to expect, to decrease stress and anxiety. TEACHING FOR A.M. Teaching about local anaesthetics is usually incorporated into the overall teaching plan about the procedure that the man will undergo. Things to highlight with the man would include the following: • Discussion of the overall procedure: • What it will feel like (any numbness, tingling, inability to move, pressure, pain, choking?) • Any anticipated discomfort • How long it will last • Concerns during the procedure: Report any discomfort and ask any questions as they arise • Discussion of the recovery: • How long it will take • Feelings to expect: tingling, numbness, pressure, itching • Pain that will be felt as the anaesthesia wears off • Measures to reduce pain in the area • Signs and symptoms to report (e.g. pain along a nerve route, palpitations, feeling faint, disorientation) Evaluate the effectiveness of the teaching program and comfort and safety measures. Constantly monitor vital signs and muscular function and sensation as it returns.

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ONLINE RESOURCES

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