Transcript PPT_18

Chapter 18:
Patient Management:
Cardiovascular System
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Alteration of the Thrombotic Process
• Three types of thrombi occur with coronary artery
disease (CAD)
– Arterial with vessel wall changes associated with CAD
– Venous and mural: formed from stasis of blood
• Treatment of thrombi
– Platelet inhibitors prevent platelet aggregation
– Anticoagulants prevent further clot formation and
minimize embolization
– Fibrinolytics dissolve existing clots
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Four Classes of Antiarrhythmic Drugs
Class
Fast
Sodium
Channel
1
Inhibits
2
Can inhibit
Slow
Effects
Calcium Reentry
Channel Circuit
Increases refractory period;
decreases automaticity and
excitability
Can
inhibit
3
4
Effect on
Action Potential
Yes
Suppresses automaticity
and catecholamines
Yes, by
Increases duration of action
bipotential; prolongs
directional refractoriness
block
Blocks
Slows automaticity of SA
node and slows AV
conduction and refractory
period
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Effects of Inotropic Meds on Heart
Increased ventricular contraction
(ventricles empty more
completely)
Decreased preload; decreased
ventricular filling pressure;
decreased pulmonary congestion
Increased stroke volume
(increased HR, increased
myocardial O2 demand)
Increased cardiac output
(increased BP, increased
coronary artery perfusion)
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Question
Which of the following is true about dopamine?
A. It increases myocardial contractility when the dose is 3
to 10 mcg/kg/min.
B. It can be given through a peripheral line.
C. It blocks the release of norepinephrine from sympathetic
nerve endings.
D. It can cause bradycardia and hypotension.
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Answer
A. It increases myocardial contractility when the dose is 3
to 10 mcg/kg/min.
Rationale: Doses >10 mcg/kg/min result in
vasoconstriction and hypertension. Dopamine should be
given through a central line to avoid extravasation into
tissues. Dopamine promotes the release of
norepinephrine. The side effects of dopamine include
tachycardia, angina, headache, and hypertension.
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Antihyperlipidemic Drugs
Drug
Action
Statins
Block
cholesterol
synthesis
Total
Cholesterol
LDL
HDL
Triglycerides
Nicotinic acid Decrease
lipoprotein
synthesis
Bile acid
sequestrants
Bind
cholesterol in
intestine
Fibrates
Decrease
synthesis of
cholesterol
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Slight
Percutaneous Coronary Interventions
Indications
• Coronary arteries with
at least 70%
narrowing
• Totally occluded
vessels
• Venous grafts or
native vessels
occluded after CABG
• Patient with evolving
MI
Contraindications
• <70% narrowing could
result in abrupt closure
• Longer survival rate
for diabetic patients
who have CABG
instead of PCI
• Not candidate for
surgery
• Anatomical limitations
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Potential Complications of PCI
• Hemorrhage: monitor ACT, sheath insertion site
• Vascular occlusion: monitor peripheral vascular
checks and pulses
• Hypotension: have fluid bolus/orders ready
• Dysrhythmias: keep emergency cart/defibrillator
nearby
• Chest pain: ongoing assessment, ST-segment
monitoring, troponin, ECG
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Question
A client is admitted to the hospital for an angioplasty.
Which of the following medications the client reported
taking the morning of the procedure should concern the
nurse?
A. Clopidogrel (Plavix)
B. Multivitamin
C. Metformin (Glucophage)
D. Lisinopril (Prinivil)
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Answer
C. Metformin (Glucophage)
Rationale: Metformin should be discontinued prior to
having any procedure with contrast dye because it
reacts with the dye, leading to lactic acid build-up.
There have been deaths reported from this interaction.
It is a research-based standard of care to give a dose
of Plavix before the procedure and one after the
procedure to help decrease risk for reclosure. The
multivitamin will have no effect on the procedure.
Clients are allowed to take their regularly prescribed
antihypertensives before the procedure.
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Physiological Effects of IABP Therapy
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IABP Therapy
Indications
• Cardiogenic shock
• Postop left ventricular
failure
• Unstable patient
requiring
interventional
cardiology procedure
Contraindications
• Incompetent aortic
valve
• Aortic aneurysm
• Severe peripheral
vascular disease is a
relative
contraindication
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Nursing Care for the Patient During
Electrical Cardioversion
• Place patient on ECG monitor, BP cuff, pulse oximeter,
O2 (as ordered).
• Establish IV for short-term anesthetic administered by
qualified health professional.
• Follow ACLS guidelines for cardioversion.
• If successful cardioversion occurs, follow with ordered
antidysrhythmics and oral anticoagulation (if applicable).
• Monitor VS, O2 sat, ECG, and mentation until stable.
• Assess skin for burns and discomfort.
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Nursing Care for Patient After
Radiofrequency Catheter Ablation
• VS, ECG, peripheral vascular checks, assess affected
groin site
• Keep leg immobilized for 4 hours (if venous access used)
or for 6 hours (if arterial access used)
• Assess for pain
• Assess fluid volume status
• Monitor for potential complications
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The NASPE/BPEG Generic Pacemaker
Code
See Box 18-22.
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Failure to Capture
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Oversensing
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Undersensing
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Question
The nurse is troubleshooting a temporary pacemaker
and notes there is a pacemaker spike but no QRS
present. What should the nurse do?
A. Increase the output setting (MA) until capture is
achieved.
B. Decrease the sensitivity (MV).
C. Replace the battery in the pacemaker.
D. Tighten the cable connection.
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Answer
A. Increase the output setting (MA) until capture is achieved
Rationale: The pacemaker malfunction is failure to capture,
and the action to take is to increase the output setting
until capture is achieved. If this does not work, then
CPR would have to be initiated if only pacemaker spikes
were present on the ECG strip. The sensitivity is
decreased when the pacemaker is oversensing, which is
interpreting tall T waves as R waves. The pacemaker is
working in this question, which is evidenced by a
pacemaker spike, so replacing the battery or tightening
the connections will not help.
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Implantable Cardioverter NBD
Defibrillator Code
Shock
Chamber
Chamber antitachycardia
pacing
delivered
Where tachydysrhythmia
detected
Pacemaker
capabilities
O - None
O - None
E - Intracardiac
electrogram
3- to 5-letter
pacemaker code
A - Atrium
A - Atrium
HHemodynamic
V - Ventricle
V - Ventricle
D - Dual
D - Dual
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Role of Nurse to Detect Problems That
May Lead to Arrest
• Cardiac
– Assess and treat chest pain quickly and aggressively.
– Search for underlying causes of dysrhythmias, new
murmurs, pericardial friction rub, distant or muffled
heart sounds, pulse parodoxus.
• Pulmonary
– Risk factors for deep vein thrombosis, pneumothorax
– Electrolyte imbalances
• Drug side effects/toxicity
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Difference Between Monophasic and
Biphasic Defibrillators
• Monophasic - shock flows from one electrode pad to the
other. Requires more peak current and more risk of
damage to heart.
• Biphasic - shock flows in one direction and then in the
opposite direction. Requires less peak current and less
risk of damage to heart.
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How Hypothermia Improves Neurological
Function During Cardiac Arrest
Mild
hypothermia
Decreased
cerebral
metabolic rate
for O2
Decreased
apoptosis
Decreased
production of
free radicals
Improved
preservation of
neurological
function
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