Exam (elaborations)
CCRN Practice Questions with verified answers- Cardiovascular
- Course
- Institution
CCRN Practice Questions with verified answers- Cardiovascular
[Show more]
Content preview
CCRN Practice Questions with verifiedanswers- Cardiovascular
A patient is in cardiac and respiratory arrest. The selection of medications to reestablish cardiac
t t t t t t t t t t t t t t
function would stimulate the sympathetic nervous system beta1 receptors. This stimulation
t t t t t t t t t t t
would result in increased automaticity and which of the
t t t t t t t t t
following?
a. Increased myocardial contractility
t t t
b. Decreased left ventricular stroke work
t t t t t
c. Decreased myocardial oxygen consumption
t t t t
d. Increased left ventricular afterload - ➡ Correct answer: a
t t t t t t t t t
Rationale: The sympathetic nervous system contains alpha, beta, and dopaminergic receptors
t t t t t t t t t t
that produce various responses when stimulated. Stimulation of beta1 receptors increases
t t t t t t t t t t t
heart rate, conductivity, and myocardial contractility. Stimulation of beta2 receptors produces
t t t t t t t t t t t
vasodilation and bronchodilation. Alpha receptors, when stimulated,
t t t t t t t
produce vasoconstriction. Stimulation of dopaminergic receptors produces a vasodilating
t t t t t t t t
effect on renal, mesenteric, coronary, and cerebral vessels.
t t t t t t t
Test-Taking Strategy: Note the helpful clue in the stem: stimulate the sympathetic system and
t t t t t t t t t t t t t
recall that this results in a fight-or-flight response—the body is responding to survive. Stroke
t t t t t t t t t t t t t t
volume would increase, so eliminate option b. Afterload would increase, but this is due to alpha
t t t t t t t t t t t t t t t t
stimulation, not beta1 stimulation, so eliminate option d. Because the heart is working faster
t t t t t t t t t t t t t t
and harder, the myocardial oxygen consumption does increase, so eliminate option c.
t t t t t t t t t t t t
Remember that the primary effects of beta1 receptors are to increase heart rate, contractility,
t t t t t t t t t t t t t t
and rate of conduction. Choose option a. A memory aid that also may help is this: beta 1 beta 2, 1
t t t t t t t t t t t t t t t t t t t t t
heart 2 lungs: beta1 affects the heart, and beta2 affects the lungs.
t t t t t t t t t t t t
A patient arrived in the emergency department with complaints of chest pain. The 12-lead
t t t t t t t t t t t t t
electrocardiogram shows ST segment elevation in leads V3 and V4. Occlusion of the affected
t t t t t t t t t t t t t t
coronary artery most likely would affect perfusion to which portion of the
t t t t t t t t t t t t
conduction system? t
a. Sinoatrial (SA) node
t t t
,b. Bachmann's bundle
t t
c. Atrioventricular (AV) node
t t t
d. Bundle of His - ➡ Correct answer: d
t t t t t t t t
Rationale: ST segment elevation in leads V3 and V4 indicates injury to the anterior wall, which
t t t t t t t t t t t t t t t
would occur with occlusion of the left anterior descending (LAD) artery. In most persons, the SA
t t t t t t t t t t t t t t t t
node, Bachmann's bundle, and AV node are supplied by the right coronary artery. The bundle of
t t t t t t t t t t t t t t t t
His is supplied by the left anterior descending artery. This is why an
t t t t t t t t t t t t t
anterior myocardial infarction may cause type II second-degree AV block or third-degree AV
t t t t t t t t t t t t
heart block at the level of the bundle of His.
t t t t t t t t t t
Test-Taking Strategy: Note that options a, b, and c are part of the supraventricular conduction
t t t t t t t t t t t t t t
system. They usually are supplied by the right coronary artery. The LAD artery supplies most of
t t t t t t t t t t t t t t t t
the interventricular conduction system, including the bundle of His and
t t t t t t t t t t
the bundle branches.
t t
Oxygen delivery (DO2) is the product of which of the following?
t t t t t t t t t t
a. PaO2, hemoglobin, mean arterial pressure
t t t t t
b. SaO2, hemoglobin, cardiac output
t t t t
c. SvO2, cardiac index, SaO2
t t t t
d. PaO2, mean arterial pressure, SvO2 - ➡ Correct answer: b
t t t t t t t t t t
Rationale: Ninety-seven percent of oxygen is attached to the hemoglobin molecule, so the SaO2
t t t t t t t t t t t t t
(arterial oxygen saturation) is a more accurate reflection of the amount of oxygen in blood. The
t t t t t t t t t t t t t t t t
PaO2 represents only the 3% that is dissolved in the plasma. The lungs must put the oxygen in
t t t t t t t t t t t t t t t t t t
the blood, the hemoglobin must carry the oxygen, and the cardiac output is a reflection of how
t t t t t t t t t t t t t t t t t
well the heart is moving the blood with its hemoglobin with attached
t t t t t t t t t t t t
oxygen. SvO2 (venous oxygen saturation) is a reflection of the oxygen reserve. SvO2 is what is
t t t t t t t t t t t t t t t
left over after the tissues have extracted what they need. The mean arterial pressure is a
t t t t t t t t t t t t t t t t
reflection of organ tissue perfusion pressure but does not indicate anything about the amount
t t t t t t t t t t t t t t
of oxygen in that blood.
t t t t t
Test-Taking Strategy: Oxygen is delivered from the arterial end, so choose an option that has
t t t t t t t t t t t t t t
SaO2 instead of SvO2. Also remember that most oxygen is carried on hemoglobin. Look for SaO2
t t t t t t t t t t t t t t t t
(not PaO2) and hemoglobin. The only option with both of these is option b.
t t t t t t t t t t t t t t
, Which of the following types of block are most likely after an anterior wall myocardial infarction
t t t t t t t t t t t t t t t
(MI)?
t
a. Sinus block
t t
b. Second-degree atrioventricular (AV) block, type I
t t t t t t
c. Second-degree AV block, type II
t t t t t
d. Third-degree AV block with junctional escape rhythm - ➡ Correct answer: c
t t t t t t t t t t t t
Rationale: Anterior MI is caused by a left anterior descending (LAD) artery lesion. The LAD
t t t t t t t t t t t t t t
artery supplies the bundle of His and bundle branches, so anterior MIs may cause blocks of the
t t t t t t t t t t t t t t t t t
bundle of His or bundle branches. Second-degree AV block type II is a block at the level of the
t t t t t t t t t t t t t t t t t t t
bundle of His. If this patient does develop a third-degree AV block, it would be at the level of the
t t t t t t t t t t t t t t t t t t t t
bundle of His, and the only escape rhythm available below the bundle of His is a ventricular
t t t t t t t t t t t t t t t t t
escape rhythm.
t t
Test-Taking Strategy: The sinus node is supplied by right coronary artery (in 55% of people) or t t t t t t t t t t t t t t t
left coronary artery (in 45% of people), so eliminate option a. Type I AV block, also called
t t t t t t t t t t t t t t t t t
Wenckebach, is a block at the AV node, and the AV node is supplied by right coronary artery (in
t t t t t t t t t t t t t t t t t t t
90% of people) or left coronary artery (10%), so eliminate option b. The
t t t t t t t t t t t t t
LAD artery supplies the bundle of His, and blocks in this area would eliminate the possibility of
t t t t t t t t t t t t t t t t
junctional escape rhythms, so eliminate option d. Choose option c.
t t t t t t t t t t
A patient develops atrial fibrillation after abdominal surgery. Her blood pressure falls from
t t t t t t t t t t t t
110/70 mm Hg to 92/68 mm Hg. The hypotension is related to which of the following?
t t t t t t t t t t t t t t t t
a. Decrease in ventricular contractility
t t t t
b. Hypovolemia
t
c. Mural thrombi
t t
d. Decrease in ventricular filling - ➡ Correct answer: d
t t t t t t t t t
Rationale: The contribution that atrial contraction makes to ventricular filling volume is
t t t t t t t t t t t
approximately 15% to 30%. Atrial fibrillation results in quivering but not contracting atria. The
t t t t t t t t t t t t t t
loss of 15% to 30% of diastolic filling volume reduces cardiac output and can have significant
t t t t t t t t t t t t t t t t
hemodynamic consequences. Although mural thrombi also are a problem, they
t t t t t t t t t t
result in an embolic phenomenon rather than a direct decrease in cardiac output. The
t t t t t t t t t t t t t
relationship between the development of atrial fibrillation and the decrease in cardiac output
t t t t t t t t t t t t t
make hypovolemia and decrease in contractility less likely.
t t t t t t t t
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Fordenken. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $15.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
76799 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now
