CARDIAC SURGERY CSC COMPREHENSIVE
QUESTIONS AND ANSWERS SURE A+
✔✔Coagulopathies associated with CBP can include which of the following:
A. Heparin rebound.
B. HIT.
C. DIC.
D. All of the above. - ✔✔D. DIC (disseminated intravascular coagulation) is a systemic
process due to massive activation of the clotting cascade. Excessive thrombin
production leads to widespread deposition of fibrin which results in intravascular clotting
and tissue ischemia. This widespread intravascular coagulation consumes platelets and
clotting factors, which then results in bleeding. In cardiac surgery involving the use of
CPB, DIC can result from prolonged contact between the blood and the artificial surface
of the bypass circuit which leads to activation of the clotting cascade.
HIT (heparin induced thrombocytopenia) ) is an immune-mediated disorder in which
antibodies are formed against the heparin-platelet factor 4 complex. Cardiac surgery
patients receive large amounts of unfractionated heparin while on CPB. Heparin binds
with platelet factor 4 released by activated platelets, forming a heparin- PF4 complex.
The body makes antibodies to this heparin-PF 4 complex, forming a heparin-PF4-
antibody complex on the platelet surface. These platelets aggregate and are removed
prematurely from the circulation leading to thrombocytopenia which increases the risk of
bleeding.
Heparin rebound is the reappearance of anticoagulant activity after adequate
neutralization of heparin with protamine at the end of surgery. A significant amount of
heparin is bound to plasma proteins and tissues, and is not completely neutralized by
protamine. This protein and tissue-bound heparin is released slowly after surgery,
producing the heparin rebound phenomenon. Heparin rebound is one of the most
common causes of postoperative bleeding after cardiac surgery.
✔✔Which of the following are true about the surgical MAZE procedure:
A. It involves ablation of the AV node and permanent pacemaker insertion.
B. It is surgical amputation of the left atrial appendage.
C. It is done to correct severe mitral stenosis.
D. It is done to prevent recurrent atrial fibrillation. - ✔✔A. The MAZE procedure creates
multiple incisions in the right and left atria in order to interrupt the reentry pathways
,responsible for maintenance of atrial fibrillation. It usually includes amputation of the left
atrial appendage as well, since this is the site of most thrombus formation in atrial
fibrillation.
AV node ablation with permanent pacemaker insertion is an electrophysiology
procedure that can be performed in patients with chronic atrial fibrillation who are
unresponsive to or intolerant of drug therapy. AV node ablation prevents the atrial
fibrillation from conducting into the ventricle but requires a ventricular pacemaker to
maintain an adequate ventricular rate.
✔✔The use of protamine to reverse heparin at the end of a cardiac surgical procedure
can result in which of the following complications:
A. Anaphylaxis and heparin rebound.
B. Acute kidney injury and SIRS.
C. Arrhythmias and pulmonary hypertension.
D. Perioperative MI and pulmonary edema. - ✔✔A. Hypersensitivity reactions, including
anaphylaxis, can occur following protamine administration. Hypotension, cardiovascular
collapse, noncardiogenic pulmonary edema, pulmonary vasoconstriction, and
pulmonary hypertension may occur. Patients with fish allergy and those using NPH
insulin are at higher risk for a protamine reaction.
Heparin rebound is the reappearance of anticoagulant activity after adequate
neutralization of heparin with protamine at the end of surgery. Heparin that is bound to
plasma proteins and tissues may not be completely neutralized by protamine. This
protein and tissue-bound heparin is released slowly after surgery, producing the heparin
rebound phenomenon after the effects of protamine are gone.
Acute kidney injury is a potential complication of CABG that can be caused by multiple
factors including intraoperative or postoperative hypotension, hemolysis, embolization to
renal arteries (associated with aortic cross clamping during CPB), and exposure to
contrast media prior to surgery. SIRS can occur secondary to the use of CPB during
surgery. Protamine use is not directly associated with acute kidney injury or SIRS.
Perioperative MI and arrhythmias are potential complications of CABG and can be due
to multiple factors including intraoperative or postoperative hypotension, embolization to
coronary arteries (associated with aortic cross clamping during CPB), acute graft
closure, and inadequate myocardial protection during CPB. Protamine use is not directly
associated with perioperative MI or arrhythmias.
Severe protamine reactions can result in pulmonary vasoconstriction with elevated PA
pressures, right ventricular dysfunction, and significant hypotension due to vasodilation.
✔✔All of the following statements are true about use of antibiotics in cardiac surgery
patients EXCEPT:
A. A cephalosporin (typically cefazolin or cefuroxime) is the antibiotic of choice in
patients without MRSA.
B. Preoperative IV prophylactic antibiotics should not be given until the patient is in the
operating suite so the administration can be timed to be 30 to 60 minutes prior to the
initial incision.
C. Vancomycin is indicated for proven or suspected MRSA.
,D. Post-operative antibiotics are continued for 7 to 10 days after surgery. - ✔✔D.
Preoperative intravenous prophylactic antibiotics are not given until the patient is in the
operating suite so the administration can be timed to be 30 to 60 minutes prior to the
initial incision. National quality standards require administration within one hour of
incision time to insure adequate tissue levels at the time of incision.
Postoperative antibiotics are given for 48 hours or less.
A cephalosporin (typically cefazolin or cefuroxime) is the antibiotic of choice in patients
without MRSA, and vancomycin, alone or in combination with other antibiotics, is
recommended in patients with MRSA.
✔✔Which of the following medications should be held prior to cardiac surgery:
A. ASA, beta blocker, IV insulin drip.
B. Clopidogrel, beta blockers, oral hypoglycemic agents.
C. Statin, beta blockers, prasugrel.
D. Clopidogrel, ACE inhibitors, oral hypoglycemic agents, NSAIDS. - ✔✔D. All
antianginal, antihypertensive, and heart failure medications should be continued up until
the time of surgery. Exceptions are ACE inhibitors and angiotensin receptor blockers,
which should be held the morning of surgery. P2Y12 inhibitors (clopidogrel, prasugrel,
ticagrelor) should be discontinued 5-7 days prior to surgery whenever possible to
reduce the risk of post op bleeding. Oral hypoglycemic agents should be held for 24
hours prior to surgery. NSAIDS should be held a few days prior to surgery to decrease
risk of bleeding and in patients with renal dysfunction.
Beta blockers should be continued or started at least 24 hours prior to surgery to reduce
the risk of postop atrial fibrillation. Statin therapy should be started at least one week
prior to surgery, as they are associated with decreased incidence of stroke, atrial
fibrillation, renal dysfunction and infection. ASA should not be discontinued in patients
with acute coronary syndrome or critical coronary artery disease. If there is an
increased risk for bleeding, or if the patient refuses blood transfusion, ASA can be held
3 days prior to surgery. If a patient is dependent on IV insulin to maintain glucose <180
mg/dL, the drip should be started preoperatively and continued through the first 24
hours postop.
✔✔All of the following are true regarding the cardiopulmonary bypass machine (heart /
lung machine) EXCEPT for:
A. Cardiopulmonary bypass provides perfusion to the other organs of the body during
surgery.
B. Cardiopulmonary bypass allows for surgery to be performed on a still and bloodless
heart.
C. Blood is drained from the aorta and reentered into the right atrium allowing for a high
pressure flow through the circuit.
D. The circuit contains an arterial line filter to remove microemboli before returning
blood to the patient. - ✔✔C. Cardiopulmonary bypass allows for surgery to be
performed on a still and bloodless heart while at the same time providing perfusion to
other organs of the body. Blood is drained (usually by gravity) from the right atrium into
a venous reservoir. From there blood is oxygenated, cooled or warmed, and returned to
the patient through an arterial cannula usually placed in the ascending aorta. The circuit
, contains an arterial line filter to remove microemboli before returning blood to the
patient. Microemboli can consist of air, blood, fat, and platelet microaggregates.
✔✔Which of the following patients should receive a transfusion of RBCs following
cardiac surgery:
A. A patient with a Hgb of 9 g/dL.
B. A stable patient with a HCT of 22%.
C. A patient who is bleeding and has a HCT of 24%.
D. A 78 year old patient with prolonged bypass time and a HCT of 26%. - ✔✔C. A
bleeding patient should be transfused to maintain a HCT of >25%. A HCT of 22-24% is
considered acceptable in stable patients (Bojar, 2011: Manual of perioperative care in
adult cardiac surgery, 5th ed.) Transfusion guidelines from the Society of Thoracic
Surgeons and the Society of Cardiovascular Anesthesiologists recommend RBCs when
the Hgb is < 6g/dL as a lifesaving strategy and for most patients when the Hgb is <
7g/dL. It is reasonable to transfuse patients with higher Hgb levels if signs of end organ
ischemia are present.
✔✔Thrombocytopenia after CABG surgery is common due to the following contributing
factors:
A. Use of the intra aortic balloon pump.
B. Platelet activation during cardiopulmonary bypass.
C. Use of heparin during or after surgery.
D. All of the above. - ✔✔D.Multiple factors in the patient post CABG affect the platelet
count. Intraoperative cardiopulmonary bypass reduces the platelet count through
platelet activation and dilution. Any patient who requires supportive intra aortic balloon
pump therapy will have a further decline in platelet count due to the effect of balloon
inflation on blood components. Medications such as heparin add the additional potential
to reduce the platelet count.
✔✔You are caring for a patient who had an aortic valve replacement due to severe
aortic stenosis causing left ventricular hypertrophy. His postoperative hemodynamic
profile is: CO = 4.6 L/min, CI = 2.4 L/min/M2, CVP = 6 mmHg, PWP = 22 mmHg. His
postoperative ejection fraction (EF) was 58%. You interpret this hemodynamic profile as
indicating:
A. Left ventricular systolic heart failure.
B. Right heart failure.
C. Left ventricular diastolic dysfunction.
D. Normal hemodynamic values. - ✔✔C. Severe aortic stenosis (AS) can cause left
ventricular hypertrophy (LVH) and remodeling that is characterized by an increased LV
wall thickness and normal or reduced LV cavity size. LVH can cause diastolic
dysfunction in which the LV is stiff and non-distensible, resulting in a higher pressure for
any given LV volume. A normal PWP is 8-12 mmHg when LV volume is normal, but in
severe AS the same normal volume causes an increase in PWP because of the thick,
stiff LV. Even though the aortic valve has been replaced, the underlying LV diastolic
dysfunction remains, resulting in higher PWP than would be seen with a normal LV.
Patients with LVH due to aortic stenosis or hypertrophic cardiomyopathy often require
QUESTIONS AND ANSWERS SURE A+
✔✔Coagulopathies associated with CBP can include which of the following:
A. Heparin rebound.
B. HIT.
C. DIC.
D. All of the above. - ✔✔D. DIC (disseminated intravascular coagulation) is a systemic
process due to massive activation of the clotting cascade. Excessive thrombin
production leads to widespread deposition of fibrin which results in intravascular clotting
and tissue ischemia. This widespread intravascular coagulation consumes platelets and
clotting factors, which then results in bleeding. In cardiac surgery involving the use of
CPB, DIC can result from prolonged contact between the blood and the artificial surface
of the bypass circuit which leads to activation of the clotting cascade.
HIT (heparin induced thrombocytopenia) ) is an immune-mediated disorder in which
antibodies are formed against the heparin-platelet factor 4 complex. Cardiac surgery
patients receive large amounts of unfractionated heparin while on CPB. Heparin binds
with platelet factor 4 released by activated platelets, forming a heparin- PF4 complex.
The body makes antibodies to this heparin-PF 4 complex, forming a heparin-PF4-
antibody complex on the platelet surface. These platelets aggregate and are removed
prematurely from the circulation leading to thrombocytopenia which increases the risk of
bleeding.
Heparin rebound is the reappearance of anticoagulant activity after adequate
neutralization of heparin with protamine at the end of surgery. A significant amount of
heparin is bound to plasma proteins and tissues, and is not completely neutralized by
protamine. This protein and tissue-bound heparin is released slowly after surgery,
producing the heparin rebound phenomenon. Heparin rebound is one of the most
common causes of postoperative bleeding after cardiac surgery.
✔✔Which of the following are true about the surgical MAZE procedure:
A. It involves ablation of the AV node and permanent pacemaker insertion.
B. It is surgical amputation of the left atrial appendage.
C. It is done to correct severe mitral stenosis.
D. It is done to prevent recurrent atrial fibrillation. - ✔✔A. The MAZE procedure creates
multiple incisions in the right and left atria in order to interrupt the reentry pathways
,responsible for maintenance of atrial fibrillation. It usually includes amputation of the left
atrial appendage as well, since this is the site of most thrombus formation in atrial
fibrillation.
AV node ablation with permanent pacemaker insertion is an electrophysiology
procedure that can be performed in patients with chronic atrial fibrillation who are
unresponsive to or intolerant of drug therapy. AV node ablation prevents the atrial
fibrillation from conducting into the ventricle but requires a ventricular pacemaker to
maintain an adequate ventricular rate.
✔✔The use of protamine to reverse heparin at the end of a cardiac surgical procedure
can result in which of the following complications:
A. Anaphylaxis and heparin rebound.
B. Acute kidney injury and SIRS.
C. Arrhythmias and pulmonary hypertension.
D. Perioperative MI and pulmonary edema. - ✔✔A. Hypersensitivity reactions, including
anaphylaxis, can occur following protamine administration. Hypotension, cardiovascular
collapse, noncardiogenic pulmonary edema, pulmonary vasoconstriction, and
pulmonary hypertension may occur. Patients with fish allergy and those using NPH
insulin are at higher risk for a protamine reaction.
Heparin rebound is the reappearance of anticoagulant activity after adequate
neutralization of heparin with protamine at the end of surgery. Heparin that is bound to
plasma proteins and tissues may not be completely neutralized by protamine. This
protein and tissue-bound heparin is released slowly after surgery, producing the heparin
rebound phenomenon after the effects of protamine are gone.
Acute kidney injury is a potential complication of CABG that can be caused by multiple
factors including intraoperative or postoperative hypotension, hemolysis, embolization to
renal arteries (associated with aortic cross clamping during CPB), and exposure to
contrast media prior to surgery. SIRS can occur secondary to the use of CPB during
surgery. Protamine use is not directly associated with acute kidney injury or SIRS.
Perioperative MI and arrhythmias are potential complications of CABG and can be due
to multiple factors including intraoperative or postoperative hypotension, embolization to
coronary arteries (associated with aortic cross clamping during CPB), acute graft
closure, and inadequate myocardial protection during CPB. Protamine use is not directly
associated with perioperative MI or arrhythmias.
Severe protamine reactions can result in pulmonary vasoconstriction with elevated PA
pressures, right ventricular dysfunction, and significant hypotension due to vasodilation.
✔✔All of the following statements are true about use of antibiotics in cardiac surgery
patients EXCEPT:
A. A cephalosporin (typically cefazolin or cefuroxime) is the antibiotic of choice in
patients without MRSA.
B. Preoperative IV prophylactic antibiotics should not be given until the patient is in the
operating suite so the administration can be timed to be 30 to 60 minutes prior to the
initial incision.
C. Vancomycin is indicated for proven or suspected MRSA.
,D. Post-operative antibiotics are continued for 7 to 10 days after surgery. - ✔✔D.
Preoperative intravenous prophylactic antibiotics are not given until the patient is in the
operating suite so the administration can be timed to be 30 to 60 minutes prior to the
initial incision. National quality standards require administration within one hour of
incision time to insure adequate tissue levels at the time of incision.
Postoperative antibiotics are given for 48 hours or less.
A cephalosporin (typically cefazolin or cefuroxime) is the antibiotic of choice in patients
without MRSA, and vancomycin, alone or in combination with other antibiotics, is
recommended in patients with MRSA.
✔✔Which of the following medications should be held prior to cardiac surgery:
A. ASA, beta blocker, IV insulin drip.
B. Clopidogrel, beta blockers, oral hypoglycemic agents.
C. Statin, beta blockers, prasugrel.
D. Clopidogrel, ACE inhibitors, oral hypoglycemic agents, NSAIDS. - ✔✔D. All
antianginal, antihypertensive, and heart failure medications should be continued up until
the time of surgery. Exceptions are ACE inhibitors and angiotensin receptor blockers,
which should be held the morning of surgery. P2Y12 inhibitors (clopidogrel, prasugrel,
ticagrelor) should be discontinued 5-7 days prior to surgery whenever possible to
reduce the risk of post op bleeding. Oral hypoglycemic agents should be held for 24
hours prior to surgery. NSAIDS should be held a few days prior to surgery to decrease
risk of bleeding and in patients with renal dysfunction.
Beta blockers should be continued or started at least 24 hours prior to surgery to reduce
the risk of postop atrial fibrillation. Statin therapy should be started at least one week
prior to surgery, as they are associated with decreased incidence of stroke, atrial
fibrillation, renal dysfunction and infection. ASA should not be discontinued in patients
with acute coronary syndrome or critical coronary artery disease. If there is an
increased risk for bleeding, or if the patient refuses blood transfusion, ASA can be held
3 days prior to surgery. If a patient is dependent on IV insulin to maintain glucose <180
mg/dL, the drip should be started preoperatively and continued through the first 24
hours postop.
✔✔All of the following are true regarding the cardiopulmonary bypass machine (heart /
lung machine) EXCEPT for:
A. Cardiopulmonary bypass provides perfusion to the other organs of the body during
surgery.
B. Cardiopulmonary bypass allows for surgery to be performed on a still and bloodless
heart.
C. Blood is drained from the aorta and reentered into the right atrium allowing for a high
pressure flow through the circuit.
D. The circuit contains an arterial line filter to remove microemboli before returning
blood to the patient. - ✔✔C. Cardiopulmonary bypass allows for surgery to be
performed on a still and bloodless heart while at the same time providing perfusion to
other organs of the body. Blood is drained (usually by gravity) from the right atrium into
a venous reservoir. From there blood is oxygenated, cooled or warmed, and returned to
the patient through an arterial cannula usually placed in the ascending aorta. The circuit
, contains an arterial line filter to remove microemboli before returning blood to the
patient. Microemboli can consist of air, blood, fat, and platelet microaggregates.
✔✔Which of the following patients should receive a transfusion of RBCs following
cardiac surgery:
A. A patient with a Hgb of 9 g/dL.
B. A stable patient with a HCT of 22%.
C. A patient who is bleeding and has a HCT of 24%.
D. A 78 year old patient with prolonged bypass time and a HCT of 26%. - ✔✔C. A
bleeding patient should be transfused to maintain a HCT of >25%. A HCT of 22-24% is
considered acceptable in stable patients (Bojar, 2011: Manual of perioperative care in
adult cardiac surgery, 5th ed.) Transfusion guidelines from the Society of Thoracic
Surgeons and the Society of Cardiovascular Anesthesiologists recommend RBCs when
the Hgb is < 6g/dL as a lifesaving strategy and for most patients when the Hgb is <
7g/dL. It is reasonable to transfuse patients with higher Hgb levels if signs of end organ
ischemia are present.
✔✔Thrombocytopenia after CABG surgery is common due to the following contributing
factors:
A. Use of the intra aortic balloon pump.
B. Platelet activation during cardiopulmonary bypass.
C. Use of heparin during or after surgery.
D. All of the above. - ✔✔D.Multiple factors in the patient post CABG affect the platelet
count. Intraoperative cardiopulmonary bypass reduces the platelet count through
platelet activation and dilution. Any patient who requires supportive intra aortic balloon
pump therapy will have a further decline in platelet count due to the effect of balloon
inflation on blood components. Medications such as heparin add the additional potential
to reduce the platelet count.
✔✔You are caring for a patient who had an aortic valve replacement due to severe
aortic stenosis causing left ventricular hypertrophy. His postoperative hemodynamic
profile is: CO = 4.6 L/min, CI = 2.4 L/min/M2, CVP = 6 mmHg, PWP = 22 mmHg. His
postoperative ejection fraction (EF) was 58%. You interpret this hemodynamic profile as
indicating:
A. Left ventricular systolic heart failure.
B. Right heart failure.
C. Left ventricular diastolic dysfunction.
D. Normal hemodynamic values. - ✔✔C. Severe aortic stenosis (AS) can cause left
ventricular hypertrophy (LVH) and remodeling that is characterized by an increased LV
wall thickness and normal or reduced LV cavity size. LVH can cause diastolic
dysfunction in which the LV is stiff and non-distensible, resulting in a higher pressure for
any given LV volume. A normal PWP is 8-12 mmHg when LV volume is normal, but in
severe AS the same normal volume causes an increase in PWP because of the thick,
stiff LV. Even though the aortic valve has been replaced, the underlying LV diastolic
dysfunction remains, resulting in higher PWP than would be seen with a normal LV.
Patients with LVH due to aortic stenosis or hypertrophic cardiomyopathy often require
