Topic 11B Flashcards

1
Q

Two Main Goals of Cardioplegia

A
  1. Prevent myocardial ischemic damage (induction/maintenance)
  2. Prevent/minimize injury (reperfusion)
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2
Q

limit detrimental changes such as (7)

A
  1. rapid cellular conversion from aerobic (O2) to anaerobic metabolism (no O2)
  2. high-energy phosphate (e.g. ATP) depletion
  3. intracellular acidosis
  4. calcium influx
  5. cell membrane disruption
  6. Intracellular Ca++ accumulation
  7. Cellular edema (inability to consume oxygen)
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3
Q

Cardioplegia Setups include:

A

crystalloid
blood
MPS

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4
Q

Crystalloid=

A

Single pass system

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5
Q

Blood cardioplegia setup=

A
  1. Fixed ratio (Bridged or Non-bridged)

2. Variable/controlled ratio

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6
Q

MPS=

A

microcardioplegia

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7
Q

3 Phases of Cardioplegia include

A

Induction of arrest
Maintenance of arrest
Reperfusion

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8
Q

Cold Induction Solutions (Crystalloid and Blood)= (4)

A
  1. ECF cardioplegia solution
  2. Potassium depolarization arrest
  3. Depolarizes the cardiac myocyte with hyperkalemia
  4. Ca++ ATPase and Na+/K+ATPase still operative and need energy
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9
Q

Pure Crystalloid Cardioplegia Induction:

Advantages (4)

A

History of use
Ease
Cheap
Low viscosity

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10
Q

Pure Crystalloid Cardioplegia Induction:

Disadvantages (6)

A
Cellular edema
Low O2 capacity
Left shift oxy-Hgb curve
Activates platelets, leukocytes, and complement
Impaired membrane stabilization
Hemodilution
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11
Q
Generic Crystalloid Solutions:
Lactated Ringer’s 1000 mL 
KCL=
MgCl=
Mannitol=
NaHCO2=
A

KCL 20 mEq
MgCl 32 mEq
Mannitol 12.5 g
NaHCO2 6.5 mEq

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12
Q

Lactated Ringer’s 1000 mL: What do you add prior to use?

A

Procaine 10% 2.7 mL

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13
Q
Generic Crystalloid Solutions:
Normosol 1000 mL 
NaHCO2=
KCL=
Mannitol=
A

NaHCO2 35 mEq
KCL 35 mEq
Mannitol 25% 12.5 g

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14
Q

Normosol 1000 mL: What do you give prior to use? (3)

A

Lidocaine 75 mg
Ntg 500 mcg
Albumin 25% 12.5 g

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15
Q

Cold Blood Cardioplegia Induction

Advantages (4)

A

O2 carrying capacity
Reduced hemodilution
Buffering/oncotic effects
O2 radical scavengers present

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16
Q

Cold Blood Cardioplegia Induction

Disadvantages (3)

A

Sludging
Oxy-Hgb curve disruption
Possible red cell damage

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17
Q

Warm Blood Cardioplegia Induction

Advantages (3)

A

Improved aerobic metabolism
Improved LV function
Improves compromised hearts

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18
Q

Warm Blood Cardioplegia Induction

Disadvantages

A

Expensive due to additives

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19
Q

Low Potassium Maintenance= (3)

A
  • Usually every 15 to 20 minutes
  • Cold blood cardioplegia or crystalloid
  • Restores arrest post wash-out
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20
Q

Preparation for Reperfusion= (6)

A
Substrate-enhanced warm cardioplegia
Limit calcium
Limit PO2
Controlled reperfusion 
De-air adequately
Avoid ventricular distension
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21
Q

Know the SV per tubing size

A

look at lab notes from last quarter

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22
Q

Controlled reperfusion=

A

The endothelium is damaged during ischemia–damage can increase through unregulated reperfusion
•Upon XC Removal: MAP → 40 mmHg for 1-2 minutes then MAP→ 70 mmHg after 2 minutes

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23
Q

Hot Shot=

A
  • Just prior to removal of the aortic cross clamp

- In addition to cross clamp drugs

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24
Q

Cross clamp drugs (4)

A
Aspartate Glutamate
Tham
Dextrose
CPD
--Due to cost: warm blood may be substituted
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25
Q

Custodial Cardioplegia =(HTK)

A

Histidine Tryptophan Ketoglutarate

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26
Q

Custodial Cardioplegia (HTK): Intracellular cardioplegia solution (4)

A

Low sodium concentration
Histidine
Tryptophan
Mannitol

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27
Q

Benefits of HTK Cardioplegia: Initial use

A

organ protection

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28
Q

Benefits of HTK Cardioplegia: Now used in cardiac surgery because (3)

A

Longer safe time of ischemia
During valve surgery
Minimally invasive procedures

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29
Q

Del Nido Solution (4:1)=

A

Plasmalyte base which is similar to ECF

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30
Q

Warm Continuous Retrograde Blood Cardioplegia:
Lichtenstein (1991) suggested that the heart
could be maintained at

A

37ºC throughout the cross clamp period to enhance perioperative myocardial function

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31
Q

Warm Continuous Retrograde Blood Cardioplegia:
“Warm Heart Trial” (1994): Studied nearly 2000 patients randomized to normothermic or hypothermic cardioplegia– they found that…

A

Normothermic patients experienced a lower incidence

of post-operative low output syndrome with no differences in mortality or myocardial infarction

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32
Q

Warm retrograde cardioplegia flow must be

A

> 100 mL/min to minimize myocardial lactate production

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33
Q

Cross clamp drugs right after cross clamp removal

A

lidocaine

mannitol

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34
Q

Single Clamp Technique=

A

One clamp episode
One unclamp episode
Distals and proximals done during one ischemic time

35
Q

Single Clamp Technique is used with

A

Used with calcified stiff aortas

36
Q

Side Biting Clamp Technique=

A

Two clamp episodes
Two unclamping episodes
Distals done during first ischemic time
Proximals done during second ischemic time

37
Q

Side Biting Clamp Technique has shorter

A

cross clamp times

38
Q

Side Biting Clamp Technique= Ischemic time is

A

only with fully clamped aorta

39
Q

Intermittent Crossclamp=

A

Increased risk of stroke

Not commonly used

40
Q

Intermittent Crossclamp: clamp time is

A

the sum of all fully ischemic times

41
Q

Fibrillatory Arrest=

A

Creates a nearly motionless heart by placing an
alternating current generator in contact with the left
ventricle

42
Q

Fibrillatory Arrest: Left side of heart can be

A

opened without the fear of ejecting air into the aorta.

43
Q

Fibrillatory Arrest: Should be used in conjunction with

A

hypothermia

44
Q

Fibrillatory Arrest: Advantages

A

Avoid cross clamp

Quiescent heart with coronary perfusion

45
Q

Fibrillatory Arrest: Disadvantages

A

Higher energy requirement than arrested heart

Spontaneous ejection will result in air emboli

46
Q

Fibrillatory Arrest: Keep ____ elevated

A

MAP

47
Q

Additional Strategies to Enhance Protection (7)

A
Anesthetic agents (↑ preconditioning)
Acute normovolemic hemodilution (↓ A fib)
Neutrophil depletion (↓ V fib)
Erythropoietin (↓ myocardial injury)
N-acetylcysteine (↓ oxidative stress)
Deferoxamine (↓lipid peroxidation)
Statins (↑NO release)
48
Q

Anesthetic agents does what?

A

(↑ preconditioning)

49
Q

Acute normovolemic hemodilution does what?

A

(↓ A fib)

50
Q

Neutrophil depletion does what?

A

(↓ V fib)

51
Q

Erythropoietin does what?

A

(↓ myocardial injury)

52
Q

N-acetylcysteine does what?

A

(↓ oxidative stress)

53
Q

Deferoxamine does what?

A

(↓lipid peroxidation)

54
Q

Statins does what?

A

(↑NO release)

55
Q

Monitoring Effectiveness for the Perfusionist

•GOAL:

A
optimize uniformity and effectiveness of delivery
(especially retrograde)
•Temperature
•pH
•Electrical Activity
56
Q

Monitoring-Temperature: Thermo coupled needle usually inserted

A

septal muscle

myocardial temp probe

57
Q

Monitoring-Temperature: Ensure delivery of

A
adequate dose
(is it going where it belongs?)
58
Q

Monitoring-Temperature: See efficacy of delivery
•Antegrade-
•Retrograde-

A
  • Antegrade-cases of aortic insufficiency

* Retrograde-cannula position ( in RA?)

59
Q

Monitoring-Temperature: Determine when

A

next dose needed

timers

60
Q

What can the perfusionist do if arrest is not occurring as

expected?

A

is aortic valve competent/insufficient
did it go the the LV
change from antegrade to retrograde
is the aortic clamp not on all the way (dilutes cardioplegia)
low K instead of high K?
bridge open or closed?
hypertrophied LV walls require a higher pressure

61
Q

Temperatures effect on pH and partial pressure assuming O2 content is constant: Increase temp=

A
Shift curve to the right
Decrease HOH
Increase H+
Increase OH-
Decrease pH
62
Q

Temperatures effect on pH and partial pressure assuming O2 content is constant: Decrease temp=

A
Shift curve to the left
Increase HOH
Decrease H+
Decrease OH-
Increase pH
63
Q

Failure to arrest can be due to

A
Aortic insufficiency
Cross-clamp or cardioplegia needle malpositioned
Inadequate solution (low potassium)
Low flow?
Low pressure?
Temperature?
64
Q

Myocardial Protection for Off-Pump Procedures:

Regional ischemia unavoidable- May become…

A

global problem when multiple vessels grafted

65
Q

Myocardial Protection for Off-Pump Procedures:

Use of suction-based stabilizers has reduced the problem of

A

working on a moving target
•Provide good exposure without excess compression of
ventricle

66
Q

Myocardial Protection for Off-Pump Procedures:

Ischemic preconditioning=

A

Brief period of vessel occlusion before occluding for

construction of the anastomosis

67
Q

Myocardial Protection for Off-Pump Procedures:

Keep normal to high…

A

systemic blood pressure
•May increase flow through collaterals
vessels

68
Q

Myocardial Protection for Off-Pump Procedures:

Attach proximal end of graft before

A

attaching distal

•Immediate re-establishment of flow to ischemic area

69
Q

Myocardial Protection for Off-Pump Procedures:

Use of _______ shunt

A

intracoronary

70
Q

Myocardial Protection for Off-Pump Procedures:

Perfusion-assisted…

A

direct coronary artery bypass (PADCAB)

•Perfuse completed grafts

71
Q

Ingredients to know (7)

A
K+
Na+
Ca++
NaHCO3
THAM
Glucose
Mannitol
72
Q

Actions of K+

A

electromechanical arrest

73
Q

Actions of Na+

A

↓ edema/intracelluar Ca++ buildup

74
Q

Actions of Ca++

A

Membrane stabilization

75
Q

Actions of NaHCO3

A

↑ pH

76
Q

Actions of THAM

A

↑ pH

77
Q

Actions of Glucose

A

Substrate, ↑ Osmolarity, ↓ edema

78
Q

Actions of Mannitol

A

↑ Osmolarity

79
Q

Solution Concentrations: KCl
High K
Low K

A

High K= 100 mmol/L

Low K= 40 mmol/L

80
Q

Solution Concentrations: THAM
High K
Low K

A

High K= 12 mmol/L

Low K= 12 mmol/L

81
Q

Solution Concentrations: MgSO4
High K
Low K

A

High K= 9 mmol/L

Low K= 9 mmol/L

82
Q

Solution Concentrations: Dextrose
High K
Low K

A

High K= 250 mmol/L

Low K= 250 mmol/L

83
Q

Solution Concentrations: CPD
High K
Low K

A

High K= 20 ml

Low K= 20 ml