McKenna's Pharmacology for Nursing, 2e

690

P A R T 8  Drugs acting on the cardiovascular system

Evaluation

comfort; and frequent rest periods to balance supply and demand of oxygen . ■ ■ 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, technique for monitoring pulse and acceptable pulse parameters, dietary measures if appropriate, measures to avoid adverse effects, warning signs of possible toxicity and need to notify healthcare provider and the need for periodic monitoring and evaluation, including ECGs and laboratory testing, to enhance knowledge about drug therapy and to promote compliance.

■ ■ Monitor response to the drug (improvement in signs and symptoms of HF, resolution of atrial arrhythmias, serum digoxin level of 0.5 to 2 ng/mL). ■ ■ Monitor for adverse effects (vision changes, arrhythmias, HF, headache, dizziness, drowsiness, GI upset, nausea). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, proper administration, adverse effects to watch for, specific measures to avoid them and the importance of continued follow-up).

■■ TABLE 44.2 Congestive heart failure and response to cardiac glycosides Response Signs and symptoms* During congestive heart failure

After full digitalisation +

Heart rate, rhythm and size

Heart hypertrophied, dilated; rate rapid, irregular; “palpitations”; auscultation—S 3 Dyspnoea on exertion; orthopnoea; tachypnoea; paroxysmal nocturnal dyspnoea; wheezing, rales, cough, haemoptysis (pulmonary oedema) Pitting oedema of dependent parts; hepatomegaly; ↑ jugular venous pressure; cyanosis; oliguria; nocturia Weakness, fatigue, anorexia, insomnia, nausea, vomiting, abdominal pain

Dilatation decreased, hypertrophy remains; rate, 70–80 beats/minute, may be regular; auscultation—no S 3 ↓ Rate of respiration; wheezes, rales gone

Lungs

↑ Cardiac output and renal blood flow leads to ↑ urine flow, ↓ oedema, ↓ signs and symptoms of poor perfusion

Peripheral

congestion

↑ Appetite: ↑ strength, energy

Other

*Because the clinical picture in heart failure varies with the stage and degree of severity, the signs and symptoms may vary considerably in different people. +Digitalisation will not overcome similar symptoms when they are caused by conditions other than heart failure. Overdosage may actually cause symptoms similar to those of heart failure (e.g. anorexia, nausea, vomiting, cardiac arrhythmias, peripheral congestion).

CRITICAL THINKING SCENARIO Inadequate digoxin absorption

THE SITUATION G.J. is an 82-year-old Caucasian woman with a 50-year history of rheumatic mitral valve disease. She has been stabilised on digoxin for 10 years in a compensated state of heart failure (HF). G.J. recently moved into an extended care facility because she was having difficulty caring for herself independently. She was examined by the admitting facility doctor and was found to be stable. Note was made of an irregular pulse of 76 beats/minute with electrocardiographic documentation of her chronic atrial fibrillation.

Three weeks after her arrival at the nursing home, G.J. began to develop progressive weakness, dyspnoea on exertion, two-pillow orthopnoea and peripheral 2+ pitting oedema. These signs and symptoms became progressively worse, and 5 days after the first indication that her HF was returning, G.J. was admitted to the hospital with a diagnosis of HF. Physical examination revealed a heart rate of 96 beats/minute with atrial fibrillation, third heart sound, rales, wheezes, 2+ pitting oedema bilaterally up to the knees, elevated jugular venous pressure, cardiomegaly, weak pulses and poor peripheral perfusion. G.J.’s serum digoxin level was 0.12 ng/mL (therapeutic range, 0.5 to 2 ng/mL).