C h a p t e r 2 0
Heart Failure and Circulatory Shock
497
are used to document ejection fraction, ventricular pre-
load, and regional wall motion.
Invasive hemodynamic monitoring may be used
for assessment in acute, life-threatening episodes of
heart failure.
37
These monitoring methods include cen-
tral venous pressure (CVP), pulmonary artery pres-
sure monitoring, measurements of cardiac output, and
intra-arterial measurements of blood pressure. Central
venous pressure reflects the amount of blood return-
ing to the right side of the heart. Measurements of CVP
are best obtained by a catheter inserted into the right
atrium through a peripheral vein or by the right atrial
port (opening) in a pulmonary artery catheter.
Ventricular volume pressures are obtained indirectly,
such as by means of a flow-directed, balloon-tipped
pulmonary artery catheter. This catheter is introduced
through a peripheral or central vein and then advanced
into the right atrium. The balloon is then inflated with
air, enabling the catheter to float through the right
ventricle into the pulmonary artery until it becomes
wedged in a small pulmonary vessel. With the balloon
inflated, the catheter monitors pulmonary capillary
pressures (i.e.,
pulmonary capillary wedge pressure
or
pulmonary artery occlusion pressure
), which reflect
pressures from the left ventricle. The pulmonary capil-
lary pressures provide a means of assessing the pump-
ing ability of the left ventricle. One type of pulmonary
artery catheter is equipped with a thermistor probe
to obtain
thermodilution measurements
of cardiac
output. Catheters with oximeters built into their tips
that permit continuous monitoring of oxygen satu-
ration (SvO
2
) also are available. Intra-arterial blood
pressure monitoring provides a means for continuous
monitoring of blood pressure. It is used in persons with
acute heart failure who need continuous blood pres-
sure monitoring, such as when aggressive intravenous
medication therapy or a mechanical assist device is
required.
Treatment
The goals of treatment for heart failure are determined
by the rapidity of onset and severity of the heart fail-
ure. Persons with acute heart failure require urgent
therapy directed at stabilizing and correcting the cause
of the cardiac dysfunction. For persons with chronic
heart failure, the goals of treatment are directed
toward relieving the symptoms, improving the quality
of life, and treating or reducing or eliminating risk fac-
tors (hypertension, diabetes, or obesity) with the long-
term goal of slowing, halting, or reversing the cardiac
dysfunction.
1,2
Treatment measures for both acute and chronic heart
failure include pharmacologic and nonpharmacologic
approaches. Mechanical support devices, including the
aortic balloon pump (for short-term acute failure) and
ventricular assist devices (VADs), can be used to sustain
life in persons with severe heart failure. Heart transplant
or a VAD remains an option for some people with end-
stage heart disease.
It is important to note that current guideline-directed
therapies only target HF patients with a reduced ejection
fraction. Therapies specific to patients with a preserved
ejection fraction or HFpEF have not been established.
Nonpharmacologic Methods
Exercise intolerance is typical of persons with chronic
heart failure. Consequently, individualized exercise
training is important to maximize muscle condition-
ing. Persons who are not accustomed to exercise and
those with more severe heart failure are started at a
lower intensity and shorter duration than those who are
largely asymptomatic. Sodium and fluid restriction and
weight management are important for all persons with
heart failure, with the level of sodium and fluid restric-
tion individualized to the severity of sodium intake, and
diuretic therapy facilitates the excretion of edema fluid.
Counseling, health teaching, and ongoing evaluation
programs assist persons with heart failure to self-manage
and cope with their treatment regimen.
38
PharmacologicTreatment
Once heart failure becomes moderate to severe, poly-
pharmacy becomes a management standard. First line
therapies for patients with a reduced ejection fraction
include
β
-adrenergic inhibitors, angiotensin-converting
enzyme (ACE)/angiotensin receptor inhibitors, and
diuretics. But for patients who are intolerant to these
drugs or who remain symptomatic despite guideline-
directed therapies, additional agents may be used, such
as aldosterone antagonists or digoxin.
1,2,39
The choice
of pharmacologic agents is determined by problems
caused by the disorder (i.e., systolic or diastolic dys-
function), those brought about by activation of com-
pensatory mechanisms (e.g., excess fluid retention,
inappropriate activation of sympathetic mechanisms),
and the person’s comorbidities.
40
Diuretics
are among
the most frequently prescribed medications for symp-
toms of volume overload.
13
They promote the excre-
tion of fluid and help to sustain cardiac output and
tissue perfusion by reducing preload and allowing the
heart to operate at a more optimal part of the Frank-
Starling curve. In emergencies, such as acute pulmonary
edema, loop diuretics such as furosemide (Lasix) can be
administered intravenously. When given intravenously,
these medications act quickly to reduce venous return
through vasodilation so that right ventricular output
and pulmonary vascular resistance are decreased. This
response to intravenous administration is extrarenal
and precedes the onset of diuresis.
The
ACE inhibitors,
which prevent the conversion of
angiotensin I to angiotensin II, have been used effectively
in the treatment of chronic heart failure.
40
The renin-
angiotensin-aldosterone system is activated early in the
course of heart failure and plays an important role in its
progression. It results in an increase in angiotensin II,
which causes vasoconstriction, unregulated ventricular
remodeling, and increased aldosterone production with
a subsequent increase in sodium and water retention by
