Advanced Nursing Concepts
Part 1: Hemodynamic Monitoring
Sandra Lewis, ARNP-BC-ADM
What Comes First?
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The PATIENT!!!
View the patient first, the equipment is
merely an adjunct.
Anatomical review
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http://www.blaufuss.org/tutorial/#
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Go to Start tutorial
Cardiovascular System Review
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Heart- pumps blood forward through the
vasculature
Arteries- carry oxygenated blood from the
heart to the body. (Constriction and Dilation
regulate the blood flow delivered)
Capillaries-microscopic vessels that allow for
exchange of gases, nutrients and metabolic
waste between plasma and the body cells
Hemodynamics
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Basic tenet is the control of adequate
oxygen delivery to the tissues.
Interrelationship of various dynamic
forces that affect the blood’s circulation
through the body.
Knowledge of pressure, flow and
resistance provide the foundation of
understanding.
Continued…
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The ability to anticipate hemodynamic
deterioration or detect adverse changes
early is a major factor in preventing
hemodynamic crisis, thus the major
reason for hemodynamic monitoring.
Indications for Hemodynamic
Monitoring
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Dehydration
Hemorrhage
GI Bleed
Burns
Surgery
Acute MI
Cardiomyopathy
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Shock: all types:
septic, cardiogenic,
neurogenic,
anaphylactic
Congestive Heart
Failure
Cont..
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Veins return deoxygenated blood to the heart. About
70% of circulating blood volume is in the venous
system at any one time.
Blood has both a cellular and fluid component.
About 60% of blood is plasma.
The remainder consists of RBC’s, WBC’s, platelet’s.
ERYTHROCYTES make up about 99% OF THE
CELLULAR COMPONENTS AND ARE RESPONSIBLE
FOR OXYGEN TRANSPORT.
An increase in RBC’s increases viscosity of blood.
Increased viscosity makes blood flow through smaller
vessels more difficult.
Pressure, Flow and Resistance
Basic physics law:
Pressure=Flow X Resistance
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Pressure=the force exerted
Blood Flow= the amount of fluid moved
per unit of time
Resistance=the opposition to force or
flow (influenced by the size, length and
viscosity of the fluid)
Cardiac Cycle
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Both the atria and the ventricles have filling
phases (diastole) and contraction phases
(systole)
During diastole the left and right ventricles
receive blood from the atria
During systole the ventricles squeeze blood
from the heart to the aorta and the
pulmonary artery. See figure 7.4 p.131
Atrial Kick
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Final contraction of the atrium filling the
ventricle…
Preload
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Left ventricular end-diastolic VOLUME.
The VOLUME left in the ventricle when the
mitral valve closes determines the amount of
blood ejected into the systemic circulation.
The ventricle never ejects its entire
volume…just a portion of it…usually 60-70%(
this is the EF..(ejection fraction)
The volume of blood EJECTED with each beat
is referred to as Stroke Volume (SV).
Arterial Blood Flow
Arterial blood pressure=measure of force
exerted on the arterial walls by the
blood
Afterload
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=The pressure or resistance of blood
flow out of the ventricle.
So, if arterial BP is high, the left
ventricle must exert more force to
pump blood out effectively…this
increases myocardial oxygen
requirements.
Contractility
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A measure of how forcefully the
ventricle contracts to eject its volume.
It is the intrinsic ability of the muscle
fibers to shorten.
Systemic Vascular Resistance
(SVR)
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THE major factor that influences SVR is
the lumen (diameter) of the vessel.
This is an important concept, often in
the critical care setting, medications are
used to alter the lumen size of systemic
vessels (primarily the arterioles).
Hemodynamic Monitoring
Equipment
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All contain: a transducer, monitor, and
fluid filled catheter, tubing and flush
system
Swan-Ganz Cath
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Normally has four ports (can have another proximal
lumen for fluids or medication infusion)
The thermistor lumen is used to measure cardiac
output.
The proximal port is used to measure right atrial
pressure
Distal lumen measures pulmonary artery pressure
The balloon port has a special 1.5 ml syringe
connected…this is used to measure PCWP
Functions of the Catheter
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Continuous hemodynamic monitoring,
assessing vascular tone, myocardial
contractility, and fluid balance.
Measures PAP, CVP, and allows
hemodynamic calculations. Cardiac
output can be determined using
thermodilution.
Transvenous pacing
Complications of a Swan/Ganz
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Infection
Dysrhytmias
Air Embolism
Pulmonary thromboembolism
Pulmonary artery rupture
Pulmonary Infarction
See table 7-1 p. 147
Arterial Monitoring
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An invasive technique for monitoring
arterial blood pressure.
Preferred in unstable patients because
it is accurate and continuous
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Allen's test
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A test for integrity of the radial and ulnar arteries at
the wrist. The examiner compresses the patient's
radial and ulnar arteries at the wrist. The patient is
then asked to open and close the hand rapidly until
the palm appears white. The examiner then releases
either the radial or the ulnar artery and looks for
return of pink color and circulation to the hand. The
test is then repeated releasing the other artery. The
hand should return to its pink color within 6 seconds
if circulation through that artery is adequate.
Indications for arterial
Monitoring
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Patients requiring frequent ABG’s or lab
work
Patients with low flow states,
hypotensive
Patients with severe hypertension
Patients with severe vasoconstriction or
vasodilation.
Arterial Lines
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Placed in an artery, usually the radial,
but can use femoral, or brachial.
Connected to a pressurized source
Complications include: thrombosis,
embolism, blood loss, infection
Tubing and transducer replaced every
96 hours.
Continued, Caveats
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Invasive monitoring is more accurate
Invasive BP should by higher than cuff BP
If cuff BP is higher look for equipment
malfunction or technical error
A dampened wave form can indicate a move
toward hypotension…an immediate cuff
pressure should be obtained
Nursing Implications
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Prevent or reduce the potential for
complications.
Maintain 300mmHg on bag
Maintain continuous flow through tubing
Aseptic dressing change
Sterile caps on openings
Change tubing q 96 hrs.
5 min hold on discontinued site
Arterial Measurements
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The systolic pressure is measured at the
peak of the waveform.
See fig. 7-10 p137
This pressure reflects the function of
the left ventricle.
NORMAL value=100-130 mmHg
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The LOWEST point on the waveform
represents the end diastolic pressure.
This pressure reflects systemic
resistance.
Normal diastolic pressure is 60-90
mmHg
Dicrotic notch
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The small notch on the downstroke of
the wave form.
It represents the closure of the aortic
valve.
This is the reference point between the
systolic and diastolic phases of the
cardiac cycle.
Mean Arterial Pressure/MAP
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Is a calculated pressure that closely estimates
the perfusion pressure in the aorta and its
branches.
It represents the average systemic arterial
pressure during the ENTIRE CARDIAC CYCLE.
Normal MAP = 70-100 mmHg
MAP MUST be maintained above 60 for the
major organs to perfuse.
CVP/ Right Atrial Pressure
Monitoring
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A direct measure of the right atrium
pressure
Clinical significance: REFLECTS RIGHT
VENTRICULAR DIASTOLIC PRESSURE
Abnormalities in RAP are caused by
conditions that alter venous tone, blood
volume, or right ventricular contractility
Cont…
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Low RAP indicates hypovolemia that
may be attributed to dehydration, acute
blood loss, extreme vasodilation (as in
sepsis)
High RAP indicates severe
vasoconstriction, fluid overload,
pulmonary hypertension