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

■ ■ Monitor pulse, respiration, blood pressure, ECG and cardiac output continually during administration to assess systemic response to CNS depression and provide appropriate support as needed. ■ ■ Monitor temperature and reflexes because dose adjustment may be needed to alleviate potential problems and to maximise overall benefit with the least toxicity. ■ ■ Institute safety precautions, such as side rails, and monitor person until the recovery phase is complete and the person is conscious and able to move and communicate to ensure safety. ■ ■ Provide comfort measures to help the person tolerate drug effects. Provide pain relief as appropriate, along with reassurance and support to deal with the effects of anaesthesia and loss of control , skin care and turning to prevent skin breakdown and supportive care for conditions such as hypotension and bronchospasm. ■ ■ Offer support and encouragement to help the person cope with the procedure and the drugs being used. ■ ■ Provide preoperative teaching, realising that most individuals who receive the drug will be unconscious or will be receiving teaching about a particular procedure: –– Information about the anaesthetic (e.g. what to expect, rate of onset, time to recovery) –– Medications that may be used preoperatively –– Effects of the medication on the person preoperatively –– Measures to maintain the person’s safety preoperatively and during recovery –– How the person will feel during the recovery phase –– Signs and symptoms to report during recovery and afterward Evaluation ■ ■ Monitor response to the drug (analgesia, loss of consciousness). ■ ■ Monitor for adverse effects (respiratory depression, hypotension, bronchospasm, slowed GI activity, skin breakdown, malignant hyperthermia). ■ ■ Evaluate the effectiveness of the teaching plan (person can relate anticipated effects of the drug and the recovery process). ■ ■ Monitor the effectiveness of comfort and safety measures.

■■ General anaesthetics must be administered by doctors or anaesthetists trained in their administration and prepared to provide constant monitoring and life support measures to assist the person when the CNS is depressed. ■■ General anaesthetics include barbiturates and non-barbiturate drugs, which are administered parenterally, and anaesthetic gases and volatile liquids, which are administered through inhalation. ■■ People receiving general anaesthetics must be constantly monitored because the CNS depression can cause respiratory arrest, cardiovascular reactions including hypotension and alterations in GI activity that can lead to nausea and vomiting. LOCAL ANAESTHESIA Local anaesthesia refers to a loss of sensation in limited areas of the body. It can be achieved by several differ- ent methods: topical administration, infiltration, field block, nerve block and intravenous regional anaesthesia. Topical administration Topical local anaesthesia involves the application of a cream, lotion, ointment or drop of a local anaesthetic to traumatised skin to relieve pain. It can also involve applying these forms to the mucous membranes in the eye, nose, throat, mouth, urethra, anus or rectum to relieve pain or to anaesthetise the area to facilitate a medical procedure. Although systemic absorption is rare with topical application, it can occur if there is damage or breakdown of the tissues in the area. Infiltration Infiltration local anaesthesia involves injecting the anaes- thetic directly into the tissues to be treated (e.g. sutured, drilled, cut). This injection brings the anaesthetic into contact with the nerve endings in the area and prevents them from transmitting nerve impulses to the brain. Field block Field block local anaesthesia involves injecting the anaes- thetic all around the area that will be affected by the procedure or surgery. This is more intense than infiltra- tion anaesthesia because the anaesthetic agent comes in contact with all of the nerve endings surrounding the area. This type of block is often used for tooth extractions. Nerve block Nerve block local anaesthesia involves injecting the anaesthetic at some point along the nerve or nerves that