CV Surgery Flashcards

1
Q

What population is at higher risk for cardiac surgery and why?

A

Females older than 70, had protective estrogen so diagnosed later
Vasculature much smaller (targets)

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2
Q

What is the best indicator for post operative functional status in cardiac patients?

A

Ejection fraction

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3
Q

What is the gold standard in determining cardiac functional status?

A

Cardiac cath, gives a full picture of the coronaries

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4
Q

What interventions are used to decrease cardiac O2 utilization for CV surgery?

A

Anesthesia
Hypothermia
Electrical silence (cardioplegia)
Emptying the cardiac chambers, especially the LV

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5
Q

What technique is used to maintain adequate perfusion since the blood has a decreased viscosity from hypothermia?

A

Hemodilution and acceptable perfusion pressure

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6
Q

What two organs are at the most risk for injury from CV surgery?

A

The brain and kidneys

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7
Q

Why is it important to know if the CV patient has had a history of groin or leg vascular surgery?

A

These are used as graft sites or cannulation

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8
Q

What is the difference between HIT-1 and HIT-2?

A

HIT 1 usually not as bad self limiting

HIT2 worse and is cause by an immune mediated response

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9
Q

What drugs can be given if a patient is allergic to heparin?

A

Low molecular weight heparin or heparinoids

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10
Q

What is heparin resistance?

A

The need for greater amount of heparin to obtain the desired ACT

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11
Q

What can be given if a patient is heparin resistant?

A

AT III (in cryo)

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12
Q

What type of EKG should be in place for CV surgery?

A

5 electrode (7 leads), show two different lead on monitor at a time

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13
Q

Where are alternative sites for the pulse oximeter in CV patients?

A

Ear, lip or tongue

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14
Q

Where are arterial lines typically placed for CV surgery?

A

Radial unless using as bypass vessel conduit

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15
Q

What needs to be done before a TEE can be placed?

A

Empty the stomach

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16
Q

Why is it essential to monitor more than one temperature site during CV surgery?

A

Each temperature site measures different blood supply (vessel rich, vessel poor)

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17
Q

What are typically the three locations to monitor temperature during CV surgery?

A

The bladder, esophageal and skin

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18
Q

What should always be checked prior to placing an a-line?

A

The Allen test, measures collateral circulation to radial and ulnar arteries

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19
Q

At what temperature should the provider never warm the CV patient due to poor neurologic outcomes?

A

Greater than 37C

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20
Q

Why is the ulnar artery starting to be used more frequently as an arterial line site?

A

The radial can be used as a graft

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21
Q

Why is it preferred to place a left axillary a line if required compared to a right?

A

The left lies distal to the aortic arch and great vessels and decrease the risk of cerebral embolization

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22
Q

What two a line sites would resemble the aortic pressure waveforms?

A

Axillary and Femoral

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23
Q

What invasive monitor is a standard in monitoring CV surgical patients?

A

Pulmonary artery catheter

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24
Q

What is the most important application of CVP monitoring?

A

Provide an estimate of the adequacy of circulating blood volume and right ventricular preload

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25
Q

Where is the most common location to place a PAC?

A

The IJ, it is the most direct route

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26
Q

In what cases will the PAC not estimate LV?

A

Lung disease or Valve pathology

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27
Q

At what length is the provider expected to be in the RA, RV and the PA?

A

RA 10
RV 20
PA 30

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28
Q

How might the provider tell from the monitor that they have advanced from the RV to the PA?

A

The diastolic pressure is higher in the PA

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29
Q

Why don’t we typically wedge in CV surgery?

A

The catheter gets cold and there is a potential for the balloon to rupture

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30
Q

What pressure can be used in place of the wedge?

A

PA diastolic = wedge (unless pulmonary HTN and mitral valve function)

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31
Q

What can a wedge pressure of 20 indicate?

A

Normal compliance when given preload
External pressure
Stiff ventricle

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32
Q

What is the most common arrhythmia from PAC placement?

A

RV ectopy

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33
Q

Why is it so dangerous to place a PAC in a patient with a LBBB?

A

RBBB can be caused by PAC placements and then you have a total blockage

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34
Q

What is the most common complication of PAC placement from a subclavian approach?

A

Pneumothorax

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35
Q

What is the most common mechanical error from PAC placement?

A

Arterial puncture compared to venous

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36
Q

What is the most common life threatening complication of PAC placement?

A

Cardiac tamponade

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37
Q

Why are TEEs used?

A

Helps diagnose underlying mechanisms ascribed to several scenarios (ventricle filling, CO, tamponade, calcifications, thrombus)

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38
Q

What are contraindications to the used of TEE?

A

Esophageal pathology

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39
Q

If calcifications are found when performing TEE what does that indicate?

A

That the surgeon should not clamp the aorta because of the risk of breaking off and going to the brain

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40
Q

What are the most important TEE views?

A
Four chamber view
Long axis view
Two chamber view
Mild short axis
Basal short axis
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41
Q

What are specific recommendations for hemodynamics in patients with aortic and mitral stenosis prior to going on pump?

A

Maintain preload and SVR

HR 50-80 NSR

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42
Q

What are specific recommendations for hemodynamics in patients with aortic and mitral regurgitation prior to going on pump?

A

Maintain preload
Low SVR
Low HR 60-80 NSR

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43
Q

What CV med is given pre op as a standard of practice in CV surgery?

A

Beta blockers

44
Q

Why is methylprednisolone given to patients that go on cardiac bypass?

A

To avoid pump syndrome

45
Q

What type of patient population would be the best for a high narcotic technique?

A

Patients with a low EF

46
Q

Why is nitrous avoided in CV surgery when bypass is used?

A

Any existing air is going to expand with nitrous

47
Q

What causes cardiac depression in volatile anesthetics?

A

Alterations in intracellular Ca

48
Q

What must the provider do prior to sternotomy?

A

Turn off the vent and deflate the lungs

49
Q

Patients with what type of heart disease are at high risk for intraoperative ischemia?

A

Unfavorable coronary anatomy
Proximal coronary stenosis
Severe LV dysfunction

50
Q

What artery is often used as a graft in CV surgery?

A

Mammary artery

51
Q

What must be given prior to cannulation?

A

Heparin 300u/kg

52
Q

Where should the PAC be pulled back to once on bypass?

A

RA

53
Q

What chamber of the heart is most likely to be entered with sternotomy?

A

RV

54
Q

How should the BP be manipulated prior to aortic cannulation?

A

SBP dropped to 80mmHg,decreases blood loss and decrease the chance of dissection

55
Q

What vein is usually dissected for CV surgery?

A

Saphenous vein

56
Q

What should the ACT be prior to going on pump?

A

> 400 seconds

57
Q

How should heparin be given and rechecked?

A

Give in central line and wait three minutes to recheck ACT

58
Q

What should be used as a guideline in reducing heparin?

A

The patient’s dose response curve should be used to calculate the amount of supplemental heparin needed to maintain ACT at a safe level on pump

59
Q

What does the ACT measure?

A

The inhibiting effect that heparin and other anrtithrombotic medication have on the bodys clotting system (not actually heparin level)

60
Q

When should protamine be given?

A

If the ACT is greater than 150 seconds at the end of the operation

61
Q

When should an ACT be checked to ensure adequate heparin reversal?

A

15-30 minutes postoperatively

62
Q

What is the fibrilatory threshold for temperature?

A

32 degrees, causes LV to expand and decreased subendocardial perfusion

63
Q

Where are the two locations that cardioplegic solution is injected?

A

Aorta anterograde and Coronary sinus retrograde

64
Q

How does hypothermia affect the blood?

A

Alters platelet function and reduces fibrin enzyme function
Inhibits initiation of thrombin formation
Reduces metabolic demand, increases tolerance to ischemia

65
Q

What is the CPB machine usually primed with?

A

1500-2000mL of asanguinous fluid consisting primarily of a balanced salt solution

66
Q

What is an acceptable Hct on pump?

A

20% and may be lower with Jehova’s Witness

Hgb 7

67
Q

What factor independently determines post op renal failure on pump?

A

The degree of hemodilution is independently associated with post op renal failure

68
Q

When should the provider turn off the vent when going on bypass?

A

When the PA goes flat

69
Q

What are arrhythmias usually associated with when going on bypass?

A

Cardiac manipulation and cannulation

70
Q

What are the most frequently encountered pre CPB problems?

A
Arrhythmias
HTN
HoTH
Heart failure
Bleeding
71
Q

What affects does hypothermia have on the cells?

A

There is a favorable balance between O2 supply and demand
Decreased exicitotoxic neurotransmitter release
Decreased blood brain barrier permeability
Decreased inflammatory response

72
Q

What are the initiators of the inflammatory cascade on pump?

A

Systemic cytokine signaling and complement system activation and Expression of cell adhesion molecules

73
Q

What are the effectors of the inflammatory cascade on pump?

A

Margination of neutrophils, monocytes and platelets and the release of granule proteases

74
Q

Where is the aortic clamp placed when going on bypass?

A

Above the aortic valve

75
Q

How can the provider determine how diseased a patients heart is when going on pump?

A

They do not arrest quickly and often will see v-tach

76
Q

What are hemodynamic goals for a patient on cardiac bypass?

A

Mild to moderate hypothermia (30-32) ad keep MAP at 50-70mmHg

77
Q

What can occur in a patient with an incompetent aortic valve when going on bypass?

A

Cardioplegia will go forward into coronary arteries but also retrograde into the LV, this increases left ventricular end diastolic pressure and decreases CPP

78
Q

How much potassium is in the cardioplegia solution?

A

26mEq/L

79
Q

When are the two points to redose all medications during cardiac bypass?

A

Redose all agents when going on pump (dilutional effect) and when warming the patient

80
Q

When is the most common for patients on bypass to have recall?

A

When rewarming the patient

81
Q

What is the rule of thumb for the amount of time spent reperfusing a patient?

A

Reperfusion time should be half of the time spent on pump

82
Q

What is thought to cause reperfusion injury?

A

Free radical mediated cellular membrane disruption

83
Q

What is the purpose of using a partial occlusion clamp?

A

Allow some perfusion but still occluding some blood flow

84
Q

How should an open heart be defibrillated?

A

Direct contact defibrillate at 10-13 joules

85
Q

How should a provider treat a patient with an existing pacemaker prior to CV surgery?

A

Convert to asynchronous (using magnet) to ensure capture during chest entry

86
Q

What should the provider do if the patient has a complete hear block when weaning from bypass?

A

Pace at 85-90bpm and make sure mA is acceptable

87
Q

What are the ABCs of coming off pump?

A

Airway, turn on the vent
Bureaucracy, K, acid base, hematocrit and repercussion
C: Rhythm, a paced of V-paced need adequate rate around 90
Contractility make sure oxygen is okay before starting EPI

88
Q

What is the best monitor for coming off bypass?

A

The eye, look at the heart you will see how vigorously it beats and

89
Q

How can the provider calculate after load when the patient is coming off bypass?

A

Ask what the flow (CO)

90
Q

What should the temperature be when complete rewarming?

A

Temp >35

91
Q

What allergies are associated with protamine?

A

Salmon sperm, seafood and protamine zinc insulin

92
Q

What is the mechanism of action of protamine?

A

Forms a tight ionic bond with the acidic sulfhydryl group of the heparin molecule on the basis of a 1:1mg ratio and prevents formation of H complex with AT III

93
Q

Why does heparin rebound occur?

A

Protamine half life is shorter than heparin by 30-60m

94
Q

What can occur if a dose 2-3x the normal reversal dose of protamine is given?

A

Has an anticoagulant effect

95
Q

How should protamine be administered?

A

SLOWLY can cause type I, II and III hypersensitivity reactions

96
Q

What should be done prior to closing the chest wires?

A

Shoot a CO to ensure everything is okay before closing

97
Q

What are major challenges faced in post CPB?

A
Recall
Bleeding
Organ hypo perfusion
Systemic inflammation response
Residual hypothermia
Repercussion inssues
98
Q

What is the major cause of poor pulmonary outcome after cardiac surgery?

A

Cardiac dysfunction, low CO states directly and indirectly contribute to pulmonary dysfunction

99
Q

How does CPB offer additional insults to the respiratory system?

A

Directly thought the activation of the inflammatory resins and indirectly through the decreased perfusion and lack of ventilation of the lungs

100
Q

How are the kidneys affected post op by bypass?

A

Renal dysfunction remains a serious complication of cardiac surgery

101
Q

What is the best way to prevent renal injury post bypass?

A

Maintain CO and perfusion pressure

102
Q

How does hypothermia affect the patient post bypass?

A

Cold and SVR high, they look stable but intravascular volume is underestimated

103
Q

What can further interfere with ventilation after bypass?

A

Shivering, increases O2 demand by 200-400%

104
Q

Why might a patient experience hypokalemia after bypass?

A

Post CPB diuretics

105
Q

What are typically the causes of acid base issues after bypass?

A

Low CO or elevated citrate levels

106
Q

What acid/base issue is seen with SNP administration?

A

Cyanide toxicity are acidotic

107
Q

Why might right ventricular dysfunction or failure occur after CPB?

A

Inadequate myocardial protection, inadequate revascularization with resultant right ventricular ischemia or infarction, preexisting pulmonary HTN, intracoronary or pulmonary air embolism, chronic mitral valve disease or tricuspid regurgitation