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TECHNICAL CORNER: THE SIGNIFICANCE OF CONGESTIVE HEART FAILURE
IN THE SLEEP LAB By Chad Eiken, RPSGT
QUESTION
What is congestive heart failure, and what should a sleep technologist know about it?
ANSWER
Congestive heart failure (CHF) is an epidemic. As of 2007,
there were five million Americans with a diagnosis of CHF
along with 600,000 new cases and one million hospitalizations
occurring annually. Although some evidence suggests that these
numbers are increasing, new innovations in the management
of CHF have resulted in slight improvements in survival.1 The
rapid increase in the elderly population in the U.S. undoubtedly
plays a role in the increasing prevalence of CHF. Since the
prevalence of both CHF and obstructive sleep
apnea increases with age, the likelihood is high
that elderly patients may have coexisting OSA
and CHF:
There is a high prevalence of sleep disordered
breathing in congestive heart failure patients
with mild and severe disease. This manifests
as either central, mixed or obstructive sleep
apnea/hypopnea. Sleep disordered breathing
contributes to a poorer prognosis in CHF
patients although it is rarely associated with
daytime sleepiness.2
Therefore, it is important for sleep technologists
to be aware of CHF, which is defined as:
heart or only on one side. As a result both the impact on the
body and the patient’s presenting symptoms may differ.
For instance, a patient may present to the sleep center with
peripheral edema. Although there are many causes of leg
edema, right-sided heart failure should always be considered.
Neck vein engorgment (jugular venous distension or JVD) occurring together with leg edema confirms the presence of rightsided heart failure (cor pulmonale). This occurs because of the
diminished ability of the right heart to sufficiently move blood
from the systemic veins to the pulmonary circuit of the vascular
system. The “congestion” occurring in the right ventricle causes
the volume of blood in the peripheral circulation to increase
(volume overload).
With left-sided heart failure, it is more difficult to observe the effect of volume overload.
When the left heart is unable to adequately
move blood from the pulmonary veins to the
systemic arteries, there is a volume overload in
the pulmonary circuit. It is important for the
sleep technologist to be aware of this scenario
because it may result in Cheyne-Stokes respirations. This breathing pattern is a significant
form of sleep-disordered breathing that may
cause excessive daytime sleepiness, frequent
arousals and awakenings during sleep, and
insomnia complaints. It also will increase the
workload of the heart, potentially causing more
damage to the heart. CHF patients who have
nocturnal Cheyne-Stokes respirations appear
to have a higher risk of mortality than those
who have a normal breathing pattern, despite a
similar degree of left ventricular dysfunction.4
The interface of Cheyne-Stokes respirations and left-sided CHF is complex. During
non-rapid eye movement (NREM) sleep the
balance of oxygen and carbon dioxide is gauged
by specialized chemoreceptors located in the aortic arch and
the carotid bodies. When these receptors sense that the blood
is too acidic (think of this as containing too much carbon
dioxide), the respiratory system compensates by increasing effort and tidal volume. This will efficiently lower the acidity of
blood in the pulmonary circuit. However, with left-side heart
failure there is a volume overload in the pulmonary circuit, and
decreased efficiency when moving blood from the pulmonary
circuit to the systemic arteries. Therefore, there is a lag from
the time that blood is in the pulmonary circuit to the time
when the acidity of the blood can be evaluated at the aortic
arch/carotid bodies.
As the blood reaches the aortic arch, the chemoreceptors determine that the acidity has decreased somewhat rapidly (think
of this as lacking carbon dioxide). The respiratory system reacts
by relaxing in terms of effort until the acidity of the blood has
been raised, and the cycle is repeated.
The way the respiratory system reacts during this cycle is a
result of the hypercapnic drive, which is what gives Cheyne-
CHF patients
who have
nocturnal
Cheyne-Stokes
respirations
appear to have
a higher risk of
mortality than
those who
have a normal
breathing
pattern…
An abnormal condition that reflects impaired
cardiac pumping. Its causes include myocardial infarction, ischemic heart disease, and
cardiomyopathy. Failure of the ventricles to
eject blood efficiently results in volume overload, ventricular dilation, and elevated intracardiac pressure.
Increased pressure in the left side of the heart causes pulmonary congestion; increased volume in the right side causes
systemic venous congestion and peripheral edema.3
The key points to remember are that poor ventricular ejection
= volume overload, left side = pulmonary congestion, and right
side = systemic venous congestion/peripheral edema. Diminished
cardiac function can exist in both the left and right sides of the
Chad Eiken, RPSGT
Chad Eiken, RPSGT, has been in the sleep
field since 2005 and is the lead sleep
technologist for Region's Hospital in St.
Paul, Minn.
A2Zzz 18.4 | December 2009
29
Stokes respirations the hallmark waxing-and-waning effort.
Prior to performing polysomnography in a patient who has
CHF, it can be beneficial to review a recent echocardiogram
to note the left-ventricular ejection fraction (LVEF). This is
the proportion of blood pumped out of the heart in relation to
the volume of blood present at the end of diastole. In healthy
patients this should be at least 50 to 65 percent. A LVEF < 40
percent is indicative of systolic dysfunction. Up to 45 percent
of patients with such dysfunction have been shown to exhibit
nocturnal Cheyne-Stokes respirations.5 One study showed that
the LVEF of patients who had been successfully treated with
servo-ventilation increased from 11.6 to 16.4 percent over a
six-month period.1 Although CHF sometimes is asymptomatic,
the presence of CheyneStokes respirations during polysomnography may prompt the physician to evaluate the patient for
CHF if there are no other reasons for the patient to exhibit this
breathing pattern.
The outcome of CHF is generally poor, with the American
Heart Association estimating 50,000 deaths annually. However,
long-term mortality rates have been somewhat stable for the
past decade. This is most likely a result of innovations in CHF
management. Evidence suggests that Cheyne-Stokes respirations have a largely negative effect on prognosis, and proper
management of Cheyne-Stokes respirations can be of great
benefit to the patient. Therefore, it is likely that sleep technologists will have an increasingly significant role in the management of patients with CHF.
REFERENCES
1. Hosenpud JD, Greenberg BH, editors. Congestive
heart failure. Philadelphia: Lippincott Williams &
Wilkins;2007.
2.
Hastings PC, Vazir A, Meadows GE, et al. Adaptive servo-ventilation in heart failure patients with sleep apnea: A
real world study. Int J Cardiol. 2008 Sep 19. [Epub ahead
of print].
3.
Anderson KN, editor. Congestive heart failure. In:
Mosby’s medical, nursing, & allied health dictionary. 6th
ed. C.V. Mosby;2001.
4. Lanfranchi PA, Braghiroli A, Bosimini E, et al. Prognostic value of nocturnal Cheyne-Stokes respiration in chronic heart failure. Circulation. 1999 Mar
23;99(11):1435-40.
5. Köhnlein T, Hoffmann B, Klein H, Welte T. CheyneStokes respiration during sleep in patients with low
cardiac output due to chronic coronary artery disease or
dilated cardiomyopathy. Eur Respir J. 1998;12:124s. 
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