McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 4 4 Cardiotonic agents

to avoid hypersensitivity reactions ; acute aortic or pulmonic valvular disease, acute MI or fluid volume deficit and ventricular arrhythmias, which could be exacerbated by these drugs ; and current status of pregnancy and breastfeeding to prevent potential adverse effects to the fetus or baby. ■ ■ Perform a physical assessment to establish baseline status before beginning therapy, determine the effectiveness of therapy and evaluate for any potential adverse effects. ■ ■ Assess cardiac status closely, including pulse and blood pressure, to identify changes or the presence of adverse effects ; auscultate heart sounds, noting any evidence of abnormal sounds. ■ ■ Obtain the person’s weight, noting any recent increases or decreases, to determine the fluid status. ■ ■ Inspect skin and mucous membranes for colour, and check nail beds and capillary refill for evidence of perfusion. ■ ■ Examine the abdomen for distension; auscultate bowel sounds to evaluate GI motility. ■ ■ Assess voiding patterns and urinary output to provide a gross indication of renal function. ■ ■ Obtain a baseline ECG to identify rate and rhythm and evaluate for possible changes. ■ ■ Monitor the results of laboratory tests, including serum electrolyte levels, full blood count, and renal and hepatic function tests, to determine the need ■ ■ Protect the drug from light to prevent drug degradation . ■ ■ Ensure that the person has a patent intravenous access site available to allow for intravenous administration of the drug. ■ ■ Monitor pulse and blood pressure frequently during administration to monitor for adverse effects so that the dose can be altered if needed to avoid toxicity. ■ ■ Monitor input and output and record daily weight to evaluate the resolution of HF. ■ ■ Monitor platelet counts before and regularly during therapy to ensure that the dose is appropriate ; inspect the skin for bruising or petechiae to detect early signs of thrombocytopenia ; consult with the prescriber about the need to decrease the dose at the first sign of thrombocytopenia. ■ ■ Monitor intravenous injection sites and provide comfort measures if infusion is causing irritation. ■ ■ Provide life support equipment on standby in case of severe reaction to the drug or development of ventricular arrhythmias. ■ ■ Provide comfort measures to help the person tolerate drug effects. These include small, frequent meals to alleviate GI upset and anorexia ; access to for possible dose adjustment. Implementation with rationale

■■ The cardiac glycoside digoxin increases the movement of calcium into the heart muscle. This results in increased force of contraction, which increases blood flow to the kidneys (causing a diuretic effect), slows the heart rate and slows conduction through the atrioventricular node. All of these effects decrease the heart’s workload. ■■ Phosphodiesterase inhibitors block the breakdown of cAMP in the cardiac muscle. This allows more calcium to enter the cell (leading to more intense contraction) and increases the effects of sympathetic stimulation (which can lead to vasodilation but also can increase pulse, blood pressure and workload on the heart). ■■ Phosphodiesterase inhibitors are associated with severe effects. They are reserved for use in extreme situations. They are only available for IV use. CHAPTER SUMMARY ■■ HF, a condition in which the heart muscle fails to effectively pump blood through the cardiovascular system, can be the result of a damaged heart muscle and increased demand to work harder. bathroom facilities to provide needed facilities if GI upset is severe and when increased urination occurs secondary to increased cardiac output; safety precautions to protect the person if visual changes, dizziness or weakness occur s; and orientation to surroundings to support the person if CNS changes occur. ■ ■ Offer support and encouragement to help the person deal with the diagnosis and the drug regimen. ■ ■ Provide thorough teaching, including the name of the drug, dosage prescribed, measures to avoid adverse effects, warning signs of problems and the need for periodic monitoring and evaluation, to enhance knowledge about drug therapy and to promote compliance. Evaluation ■ ■ Monitor response to the drug (alleviation of signs and symptoms of HF). ■ ■ Monitor for adverse effects (hypotension, cardiac arrhythmias, GI upset, thrombocytopenia). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for, specific measures to avoid them and the importance of continued follow-up). KEY POINTS