McKenna's Pharmacology for Nursing, 2e

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P A R T 4  Drugs acting on the central and peripheral nervous systems

KEY POINTS

■ ■ Provide thorough teaching, including anaesthetic to be given, method for administration, activities involved with administering and monitoring the drug, and safety precautions. Evaluation ■ ■ Monitor the person’s response to the drug (loss of feeling in designated area). ■ ■ Monitor for adverse effects (respiratory depression, blood pressure changes, arrhythmias, GI upset, skin breakdown, injury, CNS alterations). ■ ■ Evaluate the effectiveness of the teaching plan (the person can relate the anticipated effects of the drug and the recovery process).

■■ Local anaesthetics block the depolarisation of nerve membranes, preventing the transmission of pain sensations and motor stimuli. ■■ 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.

CRITICAL THINKING SCENARIO Local anaesthesia

THE SITUATION A.M., a 32-year-old male athlete with a history of asthma (which could indicate pulmonary dysfunction), was admitted to the hospital for an inguinal hernia repair. At the person’s request, the surgeon elected to use a local anaesthetic employing spinal anaesthesia. Because the extent of the repair was unknown (A.M. had undergone two previous repairs), bupivacaine, a long-acting anaesthetic, was selected. He remained alert (blood pressure 120/64 mmHg, pulse 62 beats/minute, respiration rate 10/minute) and stable throughout the procedure. Two hours after the conclusion of the procedure, A.M. appeared agitated (blood pressure 154/68 mmHg, pulse 88 beats/ minute, respiration rate 12/minute). Although he did not complain of discomfort, he did state that he still had no feeling and had only limited movement of his legs. CRITICAL THINKING What safety precautions need to be taken? What interventions should be done at this point? How could the man be reassured? Think about the anxiety level of the man—an athlete who elected to have local anaesthesia may have a problemwith control and feel somewhat invincible. Consider the anxiety that loss of mobility and sensation in the legs may cause in a person who makes his living as an athlete. In addition, consider the expected duration of action of bupivacaine and the rate of return of function. DISCUSSION Bupivacaine is a long-acting anaesthetic with effects that may persist for several hours. The timing of the drug’s

effects should be explained to A.M., and he should be monitored for a period of time to determine whether his agitated state and slightly elevated vital signs are a result of anxiety or an unanticipated reaction to the surgery or the drug. Life-support equipment should be on standby in case his condition is a toxic drug reaction or some unanticipated problem occurring after surgery. The healthcare professional is in the best position to perform the following interventions: explaining the effects of the drug and the anticipated recovery schedule; keeping the man as flat as possible to decrease the headache usually associated with spinal anaesthesia; encouraging the man to turn from side to side periodically to allow skin care to be performed and to alleviate the risk of pressure sore development; and staying with the man as much as possible to reassure him, to answer his questions, and to encourage him to talk about his feelings and reaction. If the agitated state is caused by a stress reaction, the man should return to normal; comfort measures, teaching and reassurance should be provided. An elevated systolic pressure with a normal diastolic pressure often is an indication of a sympathetic stress response. An athlete is more likely than most people to suffer great anxiety and fear if his legs become numb and he is unable to move them. Teaching and comfort measures may be all that is needed to relieve the anxiety and ensure a good recovery. CARE GUIDE FOR A.M.: LOCAL ANAESTHESIA Assessment: History and examination Assess for allergies to local anaesthetics or to parabens,

cardiac disorders, vascular problems, hepatic dysfunction; also assess for concurrent use of suxamethonium.