C H A P T E R 4 4
Cardiotonic agents
689
Care considerations for
people receiving cardiac glycosides
Assessment: History and examination
■
■
Assess for contraindications or cautions: known
allergies to any digitalis product
to avoid
hypersensitivity reactions
; impaired kidney
function,
which could alter the excretion of the
drug
; ventricular tachycardia or fibrillation,
which
require treatment with other life-saving drugs
;
heart block, sick sinus syndrome or IHSS,
which
could be exacerbated by the drug
; acute MI,
which could lead to increased muscle damage and
infarction
; electrolyte abnormalities (increased
calcium, decreased potassium or decreased
magnesium),
which could alter the action potential
and drug effects
;
and current status of pregnancy
or breastfeeding.
■
■
Perform a physical assessment
to establish baseline
status before beginning therapy, determine the
effectiveness of therapy and evaluate for any
potential adverse effects.
■
■
Obtain the person’s weight, noting any recent
increases or decreases,
to determine the person’s
fluid status.
■
■
Assess cardiac status closely, including pulse and
blood pressure,
to identify changes requiring a
change in dosage of the drug or the presence of
adverse effects
; and auscultate heart sounds, noting
any evidence of abnormal sounds,
to identify
conduction problems.
■
■
Inspect the skin and mucous membranes for
colour, and check nail beds and capillary refill
for
evidence of perfusion.
■
■
Monitor affect, orientation and reflexes
to evaluate
central nervous system (CNS) effects of the drug.
■
■
Assess the person’s respiratory rate and auscultate
lungs
for evidence of adventitious breath sounds
to monitor for evidence of left-sided heart failure.
■
■
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 electrocardiogram (ECG)
to
identify rate and rhythm and evaluate for possible
changes.
■
■
Monitor the results of laboratory tests, including
serum electrolyte levels and renal function tests,
to
determine the need for possible dose adjustment.
Implementation with rationale
■
■
Consult with the prescriber about the need for a
loading dose when beginning therapy
to achieve
desired results as soon as possible.
■
■
Monitor apical pulse for 1 full minute before
administering the drug
to monitor for adverse
effects.
Withhold the dose if the pulse is less than
60 beats/minute in an adult or less than 90 beats/
minute in an infant; retake the pulse in 1 hour. If
the pulse remains low, document it, withhold the
drug and notify the prescriber
because the pulse
rate could indicate digoxin toxicity
(see Table 44.2
for Signs and symptoms).
■
■
Monitor the pulse for any change in quality or
rhythm
to detect arrhythmias or early signs of
toxicity.
■
■
Check the dose and preparation carefully
because
digoxin has a very small margin of safety and
inadvertent drug errors can cause serious
problems.
■
■
Check paediatric dose with extreme care
because
children are more apt to develop digoxin toxicity.
Have the dose double-checked by another nurse or
midwife before administration.
■
■
Follow dilution instructions carefully for
intravenous use; use promptly
to avoid drug
degradation.
■
■
Administer intravenous doses very slowly over at
least 5 minutes
to avoid cardiac arrhythmias and
adverse effects.
■
■
Avoid intramuscular administration,
which could
be quite painful.
■
■
Arrange for the person to be weighed at the
same time each day, in the same clothes,
to
monitor for fluid retention and HF.
Assess
dependent areas for oedema; note the amount
and degree of pitting
to evaluate the severity of
fluid retention.
■
■
Avoid administering the oral drug with food or
antacids
to avoid delays in absorption.
■
■
Maintain emergency equipment on standby:
potassium salts, lignocaine (
for treatment of
arrhythmias
), phenytoin (
for treatment of
seizures
), atropine (
to increase heart rate
) and a
cardiac monitor,
in case severe toxicity should
occur.
■
■
Obtain digoxin level as ordered; monitor the
person for therapeutic digoxin level (0.5 to
2 ng/mL)
to evaluate therapeutic dosing and to
monitor for the development of toxicity.
■
■
Provide comfort measures
to help the person
tolerate drug effects.
These include small, frequent
meals
to help alleviate GI upset or nausea
; access
to bathroom facilities if GI upset is severe and
to accommodate increased urination related to
increased cardiac output
; safety precautions
to
reduce the risk of injury secondary to weakness
and drowsiness
; adequate lighting
to accommodate
vision changes if they occur
; positioning for
