Mod2: CABG SURGERY

Question 1

_{CORONARY ARTERY BYPASS SURGERY}

What’s the purpose of Coronary Artery Bypass surgery?

Answer 1

To promote coronary blood flow to ischemic myocardium

Question 2

_{CORONARY ARTERY BYPASS SURGERY}

Methods utilized:

Answer 2

Implantation of IMA to epicardial artery w/o ligating branches

Anastomosis of saphenous vein to epicardial artery

Proximal arterial inflow source => ascending aorta

Question 3

_{CARDIOPULMONARY BYPASS - DEFINITION}

The process of taking venous, or deoxygenated blood, from the right side of the heart to a reservoir where it undergoes oxygenation and returns to arterial circulation to perfuse the rest of the body is known as:

Answer 3

Cardiopulmonary bypass (CPB)

This is the technique where blood is totally or partially diverted from the heart into a machine with gas exchange capacity and subsequently returned to the arterial circulation at appropriate pressures and flow rates

Question 4

_{CARDIOPULMONARY BYPASS - DEFINITION}

What’s the purpose of performing Cardiopulmonary bypass (CPB)?

Answer 4

To provide the cardiac surgeon with a motionless bloodless field to perform the procedure

To provide artificial ventilation and perfusion

To provide homeostasis under nonphysiologic conditions

To provide protection to vital organs through temperature regulation

Question 5

_{CARDIOPULMONARY BYPASS - DEFINITION}

Why are bypass technique non physiologic?

Answer 5

Arterial pressure is usually less than normal

Blood flow is non-pulsatile

Question 6

_{CARDIOPULMONARY BYPASS - DEFINITION}

What’s the overall gaol of CPB?

Answer 6

To maintain oxygenation and perfusion to vital organs

To minimize organ damage by utilizing various degrees of hypothermia

Question 7

_{CARDIOPULMONARY BYPASS - DEFINITION}

What provider operates the CPB machine?

Answer 7

a Perfusionist

Question 8

_{SIX BASIC COMPONENTS OF CARDIOPULMONARY BYPASS}

What are the six basic components of the CPB machine?

Answer 8

Tubing

^{(to bring deoxygenated blood away form patient and oxygenated blood to patient)}

Venous reservoir

External Pumps

Heat exchanger

Oxygenator

Arterial Filter

Question 9

_{CARDIOPULMONARY BYPASS MACHINE}

T/F: All CPB machines look the same

Answer 9

False

There are different types of CPB machine available

Question 10

_{CARDIOPULMONARY BYPASS MACHINE}

Identify the following components of the CPB machine:

Venous reservoir & blood filter

Membrane oxygenator

Heat exchanger

CPB control console

Roller pump for infusing oxygenated blood

Roller pump for infusing cardioplegia

Roller pump for controlling suction catheters

Cardioplegia reservoir & heat exchanger

Answer 10

A: Venous reservoir & blood filter

B: Membrane oxygenator

C: Heat exchanger

D1: CPB control console

D2: Roller pump for infusing oxygenated blood

D3: Roller pump for infusing cardioplegia

D4: Roller pump for controlling suction catheters

E: Cardioplegia reservoir & heat exchanger

Question 11

_{CARDIOPULMONARY BYPASS - VENOUS CANNULATION}

What are the three sites for venous cannulation during bypass surgery?

Answer 11

Right atrial appendage

SVC and IVC

Femoral vein

Question 12

_{CARDIOPULMONARY BYPASS - VENOUS CANNULATION}

What’s the most common site for cannulation during bypass surgery

Answer 12

Single cannulation in the right atrial appendage

Adequate for CABG or Aortic valve surgery

Question 13

_{CARDIOPULMONARY BYPASS - VENOUS CANNULATION}

Which cannulation option is typically chosen when a more extensive procedure is to be performed?

Answer 13

Two cannulas placed in the SVC and IVC

Used for situations in which complete bypass all of systemic venous return is directed to heart

“Open heart” procedures (MVR, TVR, etc.)

Severe RCA disease (Trying to avoid warm blood entering back into the RA)

Patients in renal failure (When the surgeon wants to reduce the amount of systemic absorption of K+)

Question 14

_{CARDIOPULMONARY BYPASS - VENOUS CANNULATION}

Which cannulation option is typically chosen either for minimally invasive CABG or redo sternotomy and why?

Answer 14

Femoral vein cannulation

This option is choosen if the pt has had a previous cardiac surgery and the surgeon is concerned about the pt crashing on pump from the possibility of sawing through vessels that are adhered to the thoracic cage?

Question 15

_{CARDIOPULMONARY BYPASS - VENOUS RESERVOIR}

How is blood drained from the right side of the heart and carried to a venous reservoir?

Answer 15

Occurs by gravity drainage or a vacuum

This is why if “low volume” alarm is heard from the CPB machine, this can be corrected by raising the bed and therefore increasing the distance between the venous reservoir and the level of the heart

Question 16

_{CARDIOPULMONARY BYPASS - VENOUS RESERVOIR}

Where does blood suctinned from the surgical field collect?

Answer 16

in the Cardiotomy reservoir…

which dumps back into Venous reservoir
Venous reservoir also collects blood from suctions placed in various areas of the heart (Cardiotomy suction, Aortic root suction, L ventricle vent) to maintain a bloodless field for the surgeon

Question 17

_{CARDIOPULMONARY BYPASS - VENOUS RESERVOIR}

T/F: Fluid and medication can be added here through sampling ports

Answer 17

True

Question 18

_{MAIN PUMPS}

Once blood is in the venous reservoir, blood is then drawn from the reservoir by

Answer 18

Roller pump, or

Centrifugal pump

Question 19

_{MAIN PUMPS}

Pumps that compress sections of the tubing along a backplate to propel blood forward are also known as:

Answer 19

Roller pumps

Flow is produced by compressing large-bore tubing in the main pumping chamber as the roller heads turn

Constant nonpulsatile flow is produced that is directly proportional to the number of revolutions/minute

Have hand crank to allow for manual pumping in case power lost

Some are capable of pulsatile flow

Question 20

_{MAIN PUMPS}

Disadvantages of Roller pump

Answer 20

Economical, but increased destruction of the blood cells

Can entrain air if venous reservoir is allowed to empty

Typically doesn’t happen because of low volume alarms

Question 21

_{MAIN PUMPS}

A pump that uses an impeller that rotates rapidly, causing a pressure drop that propels the blood sucked into the centrally located inlet into the peripheral circulation is also known as:

Answer 21

a Centrifugal Pump

Magnetically controlled, rapidly rotating impeller that propels blood into the periphery.

Pump flow will change with preload and afterload

Pressure sensitive and must be monitored by a flow meter

Any increase in distal pressure or afterload will cause the flow to decrease and must be compensated for by increasing the pump speed

Question 22

_{MAIN PUMPS}

What are advantages of Centrifugal pumps over roller pumps?

Answer 22

They do not occlude the tubing that propels blood, so there is less damage to red cells

Less traumatic to blood than roller pumps

Question 23

_{MAIN PUMPS}

What are disadvantages of Centrifugal pumps?

Answer 23

Nonpulsatile flow

Will not pump if filled with air

Systemic flow pump only, not used in vent or suction rollers

Question 24

_{MAIN PUMPS}

What is the function of the various pumps present on the CPB machines?

Answer 24

Controls C.O.

Maintains blood flow & perfusion pressures

Question 25

_{MAIN PUMPS - Pulsatile vs. Nonpulsatile Flow} Which type of pump allows for pulsatile flow? what are advantages of Pulsatile Flow?

Answer 25

Possible with **roller pump**, not centrifugal Improves tissue perfusion Enhances oxygen extraction Attenuates release of stress hormones Results in lower SVR during CPB Net result =\> ***improved renal and cerebral blood flow***

Question 26

_{MAIN PUMPS - Pulsatile vs. Nonpulsatile Flow} A study that looked at hemodynamics and function during bypass, concluded that non-pulsatile flow lead to increased incidence of acute kidney injury, even when the MAP was maintained WNL during bypass. Despites this, why is Nonpulsatile flow used more commonly?

Answer 26

Because its ***easier*** and still compatible with ***patient survival***

Question 27

_{CENTRIFUGLE VS. ROLLER PUMP} How do centrifugal pumps move blood?

Answer 27

Blood is **propelled** into the impeller

Question 28

_{CENTRIFUGLE VS. ROLLER PUMP} How does the roller pump move blood?

Answer 28

Turns and as it turns obstructs the tubing So you can see how red cells are potentially *damaged by the roller pumps*

Question 29

_{MEMBRANE OXYGENATOR} In the early days of bypass, which types of oxygenators were used?

Answer 29

Bubble oxygenators

Question 30

_{MEMBRANE OXYGENATOR} Which oxygenators have replaced bubble oxygenators and why?

Answer 30

**MEMBRANE OXYGENATORS** Have since replaced bubble oxygenators Research began to question bubble oxygenators contribution to *postoperative perfusion damage to vital organs*

Question 31

_{MEMBRANE OXYGENATOR} The blood-gas interface that has a very thin, gas permeable membrane where blood flows around the fibers and oxygen flows through is also known as:

Answer 31

MEMBRANE OXYGENATOR Coated bundle of hollow microporous polypropylene fibers tightly wound to create a large surface area

Question 32

_{MEMBRANE OXYGENATOR} In a membrane oxygenator, where do blood & gas (O2) flows take place?

Answer 32

Blood flows around fibers Gas (O2) flows through the fibers

Question 33

_{MEMBRANE OXYGENATOR} T/F: Membrane oxygenators contain a Blood-gas interface that allows blood to equilibrate with gas mixtures

Answer 33

**True** This is where *volatile anesthetics* are frequently added

Question 34

_{MEMBRANE OXYGENATOR} Arterial CO2 tension during bypass is dependent on:

Answer 34

The total gas flow past the oxygenator

Question 35

_{MEMBRANE OXYGENATOR} CO2 levels can be increased or decreased by

Answer 35

Increasing or decreasing oxygen gas flow (aka increasing/decreasing the “sweep”)

Question 36

_{MEMBRANE OXYGENATOR} Where is it placed?

Answer 36

After the centrifugal pump _{(MEMBRANE OXYGENATOR)} Before the roller pump

Question 37

_{HEAT EXCHANGER} The heat exchanger is made out of? What's its function?

Answer 37

**Stainless steel tubing** Has water in the inside that can either cool or warm the patient

Question 38

_{HEAT EXCHANGER} Benefits of Systemic hypothermia

Answer 38

Myocardial & Neurologic protection ↓ O2 consumption & metabolic requirements of vital organs For each **1° C** ↓in temperature = **8%** ↓in metabolic rate

Question 39

_{HEAT EXCHANGER} T/F: Blood flows around the tubing and the temperature can be adjusted to a desired level

Answer 39

**True** Blood flows around tubes with heated or cooled water flowing through tubes

Question 40

_{HEAT EXCHANGER} The heat exchanger also includes a filter that does what?

Answer 40

Catches bubbles that form during rewarming

Question 41

_{CATEGORIES OF HYPOTHERMIA} THESE ARE THE CATEGORIES OF HYPOTHERMIA. YOU CAN SEE THAT AS THE TEMPERATURE DECREASES, THE SAFE ARREST TIME ...

Answer 41

INCREASES MEANING LONGER TIMES ARE TOLERATED WITH COLDER DEGREES

Question 42

_{CATEGORIES OF HYPOTHERMIA} THE PROCESS BY WHICH THE PATIENT IS COOLED TO 18-28 D CELCIUS FOR AORTIC ROOT REPAIR is also known as:

Answer 42

CIRCULATORY ARREST

Question 43

_{CATEGORIES OF HYPOTHERMIA} DURING CIRCULATORY ARREST, THE BYPASS MACHINE IS..

Answer 43

STOPPED!!! SO THE SURGEON CAN MAKE THE GRAFT REPAIRS TO THE AORTIC ROOT

Question 44

_{CATEGORIES OF HYPOTHERMIA} THE MAXIMAL TIME FOR ARREST IS TYPICALLY AROUND...

Answer 44

16-20 MINUTES

Question 45

_{CATEGORIES OF HYPOTHERMIA} IT’S IMPORTANT TO NOTE THAT TEMPERATURES CANNOT BE ABRUPTLY INCREASED AFTER HYPOTHERMIA. Why not?

Answer 45

THERE IS A HIGH PROBABILITY OF PRODUCING **GASEOUS MICROEMBOLI** WHEN TEMPERATURES ARE INCREASED TOO QUICKLY This is the case BECAUSE *GAS SOLUBILITY DECREASES AS BLOOD TEMPS RISE*

Question 46

_{CATEGORIES OF HYPOTHERMIA} Rewarming too quickly can also cause...

Answer 46

**Neurologic damage**, and ## Footnote **Bypass afterdrop**

Question 47

_{CATEGORIES OF HYPOTHERMIA} The **Bypass afterdrop** is thought to be a result of...

Answer 47

*Inadequate total body warming* while on bypass Causes a *_redistribution of heat_* from the warmer *_core_* to the cooler *_shell_* tissue after weaning from bypass

Question 48

_{CATEGORIES OF HYPOTHERMIA} AS YOU RECALL IN THE FIRST LECTURE WE MENITIONED HOW ------- WAS THE IDEAL PLACE TO MONITOR TEMPERATURE.

Answer 48

THE ARTERIAL INFLOW to the patient Can also be called Arterial outflow from the CPB machine

Question 49

_{CATEGORIES OF HYPOTHERMIA} TEMPERATURE GRADIENTS BETWEEN THE ARTERIAL OUTLET (machine to pt) AND VENOUS INFLOW (pt to machine) SHOULD NOT EXCEED...

Answer 49

**10 DEG CELCIUS** *(8˚C in pediatrics)* Reason why monitor temperature at multiple sites to ensure uniform cooling and rewarming

Question 50

_{CATEGORIES OF HYPOTHERMIA} HYPOTHERMIA generally used for straight forward/routine open heart procedures is categorized as:

Answer 50

***Mild*** to ***moderate*** **hypothermia** Degrees: 32-37C (Mild), 28-32C (Moderate) Safe arrest time: 4-5”(Mild), 8-10”(Moderate)

Question 51

_{CATEGORIES OF HYPOTHERMIA} What's the temperature range and Safe arrest time for **Deep hypothermia**?

Answer 51

Degrees: **18-28˚C** Safe arrest time: *16-20”*

Question 52

_{CATEGORIES OF HYPOTHERMIA} HYPOTHERMIA used for complicated adult procedures (arch vessels) is categorized as:

Answer 52

**Profound hypothermia** Degrees: 14-18˚C Safe arrest time: 64-84”

Question 53

_{ADDITIONAL COMPONENTS} Additional components to the bypass machine include:

Answer 53

Arterial Filters Cardiotomy Basket Suction Aortic Root Suction LV vent Gas blender & flow meter Arterial line pressure monitor Temperature sensors Anesthesia vaporizers Ultrafiltration/Hemoconcentrator

Question 54

_{ADDITIONAL COMPONENTS} Where are arterial filters located?

Answer 54

In the tubing just before systemic circulation Typically place here between the oxygenator and pt as a last chance to remove emboli and air

Question 55

_{ADDITIONAL COMPONENTS} What's the purpose of the Cardiotomy?

Answer 55

Drains blood back into the venous Reservoir

Question 56

_{ADDITIONAL COMPONENTS} There are multiple suctions to remove blood from the field. These suctions include:

Answer 56

Basket suction Aortic root suction LV vent

Question 57

_{ADDITIONAL COMPONENTS} What's the purpose of the LV vent?

Answer 57

Prevents LV distension, by keeping it decompressed during the cross clamp period

Question 58

_{ADDITIONAL COMPONENTS} What could cause LV distention?

Answer 58

Aortic insufficiency and Venous drainage from the thebesian and bronchial veins Could lead to increasing wall tension, which Prevents subendocardial cardioplegia distribution Ultimately could result in myocardial ischemia

Question 59

_{ADDITIONAL COMPONENTS} What's the purpose of Gas blender & Flow meter?

Answer 59

Used to maintain appropriate O2 saturation levels and Respiratory acid-base homeostasis

Question 60

_{ADDITIONAL COMPONENTS} What's the purpose of Temperature sensors?

Answer 60

Monitor arterial, venous, & cardioplegia temperatures

Question 61

_{ADDITIONAL COMPONENTS} What's the purpose of Ultrafiltration/Hemoconcentrator?

Answer 61

Counteracts hemodilution **Increase hematocit without transfusion** Removes excess volume through dialysis or centrifugal separation of fluid and plasma components from the circulating blood volume

Question 62

_{ARTERIAL CANNULA} What's the purpose of the Arterial cannula?

Answer 62

Brings oxygenated blood back to the pt's systemic circulation via the aorta

Question 63

_{ARTERIAL CANNULA} Where is the arterial cannula placed?

Answer 63

Placed in the **ascending aorta** Distal to cross clamp Proximal to brachiocephalic/innominate artery

Question 64

_{ARTERIAL CANNULA} Which cannula is always the first cannula placed and the last cannula to be removed?

Answer 64

The arterial or **aortic cannula**

Question 65

_{ARTERIAL CANNULA} Why is the arterial/aortic cannula always the first cannula placed and the last cannula to be removed?

Answer 65

In the event of an **emergency**, the pefusionist can temporarily initiated *bypass with single aortic cannulation*

Question 66

_{ARTERIAL CANNULA} Why is **"crashing onto bypass"** short lived?

Answer 66

As the bypass machine *reserve risks* will be *depleted*, central venous cannulation must eventually be acheived

Question 67

_{ARTERIAL CANNULA} The surgeon will also request that blood pressure be dropped to a systolic pressure below 100 or a MAP below 60. Why?

Answer 67

To reduce the chance of causing **aortic dissection**

Question 68

_{ARTERIAL CANNULA} Besides the ascending aorta, in what other vessel could the arterial cannula be placed?

Answer 68

Femoral artery Axillary artery Subclavian artery

Question 69

_{CARDIOPLEGIA CANNULA} After the cross clamp is placed, the cardioplegia cannulas are placed. Where are the cardioplegia cannulas placed?

Answer 69

**Ascending aorta** Proximal to cross clamp This is called ***Antegrade cardioplegia*** Note that the coronaries are situated in the aortic root just outside the aortic valve Cardioplegia travels antegrade down the coronaries, which follows normal blood flow

Question 70

_{CARDIOPLEGIA CANNULA} What's the purpose of the cross clamp?

Answer 70

Prevents systemic absorption of the cardioplegic solution

Question 71

_{CARDIOPLEGIA CANNULA} After the cross clamp is placed, the cardioplegia cannulas are placed proximal to the cross clamp to deliver what?

Answer 71

**Potassium-rich** solution to the heart This induces *diastolic arrest* while the surgeon works on the heart

Question 72

_{CARDIOPLEGIA CANNULA} Besides the ascending aorta, where else can the cardioplegia cannula be placed?

Answer 72

In the **Coronary sinus** This is called *retrograde cardioplegia* Recall that **coronary sinus** is the where great veins dump deoxygenated blood back into the RA

Question 73

_{CARDIOPLEGIA CANNULA} Which cardioplegia approach provides greater myocardial protection and is especially important in high grade coronary obstruction?

Answer 73

**Retrograde cardioplegia** Accessed via SCV

Question 74

_{CARDIOPLEGIA CANNULA} T/F: During CABG, Cardioplegia can also be delivered into vein grafts for extra protection

Answer 74

**True**

Question 75

_CARDIOPLEGIA A hyperkalemic crystalloid solution that can either be crystalloid-based or blood-based.

Answer 75

What's **Cardioplegia?** Hyperkalemic crystalloid solution Can be crystalloid-based or blood-based

Question 76

_CARDIOPLEGIA How does the use cardioplegia provide myocardial preservation?

Answer 76

By putting the heart in a **diastolic cardiac arrest** also known as a **depolarized arrest**

Question 77

_CARDIOPLEGIA Explain how Cardioplegia causes Diastolic or Asystolic depolarized arrest

Answer 77

Going back to the fast action potential, we know that hyperkalemia causes the cell membrane to become less negative When K+-rich cardioplegia surrounds the myocyte, it increases the RMP from -90mV to -60mV to -40mV which we know is threshold That initiates a chemical AP This causes Na+ channels to become inactive, and also cause Diastolic or Asystolic depolarized arrest

Question 78

_CARDIOPLEGIA Cardioplegia can also be given either cold or warm, but why do some studies say that hypothermic cardioplegia may not be needed?

Answer 78

*Normothermic arrest* will decrease O2 consumption by more than **90%**

Question 79

_CARDIOPLEGIA How would adding cold solution to normothermic arrest affect O2 consumption?

Answer 79

Will decrease O2 consumption by more than 97%

Question 80

_{CARDIOPLEGIA SOLUTION} Cardioplegia solution varies from institution to institution Cardioplegia can be ---- based or ---- based.

Answer 80

Either **Blood** or ***crystalloid*** Blood *becoming more common, increases O2 carrying capacity*

Question 81

_{CARDIOPLEGIA SOLUTION} When will the surgeon request that the perfusionist begin giving cardioplegia?

Answer 81

Following the initiation of cardiac bypass After the aortic cross clamp is placed This causes that reduction in the membrane potential And eventually the heart will stop

Question 82

_{CARDIOPLEGIA SOLUTION} T/F: As previously mentioned, either cold or warm cardioplegia is given

Answer 82

True

Question 83

_{CARDIOPLEGIA SOLUTION} When cold cardioplegia is given, why must it be given every 15-20 minutes?

Answer 83

**Gradual washout** and **Rewarming** of the myocardium will occur Which will *increase its risk of ischemic injury*

Question 84

_{CARDIOPLEGIA SOLUTION} Temperature of Cold cardioplegia

Answer 84

**10-15˚**c

Question 85

_{CARDIOPLEGIA SOLUTION} Activity of which monitor may indicate need for additional cardioplegia

Answer 85

EKG

Question 86

_{CARDIOPLEGIA SOLUTION} Why does the cardioplegic solution also contains other components?

Answer 86

To help prevent the accumulation of **metabolites** To make the solution slightly hypertonic to reduce **edema**

Question 87

_{CARDIOPLEGIA SOLUTION} Other components found in the cardioplegic solution include:

Answer 87

Na+, Ca+, Mg+ Mannitol and/or albumin NTG (coronary dilator) HCO3 (buffer) Glucose (cellular energy) Hbg (O2-carrying) Lidocaine or procaine (membrane stabilization)

Question 88

_{CARDIOPLEGIA SOLUTION} Why does the cardioplegic solution only containd Small amounts of calcium?

Answer 88

To control excessive intracellular influx of Ca2+

Question 89

_{CARDIOPLEGIA SOLUTION} What could happen if the cardioplegic solution contained higher levels of Ca++?

Answer 89

Could cause *the heart to arrest in systole* ^{Ca++ causes contraction​} And that would drastically ***increase O2 demand***

Question 90

_{CARDIOPLEGIA SOLUTION} Why is Mannitol added to the cardioplegic solution?

Answer 90

To control cellular edema

Question 91

_{CARDIOPLEGIA SOLUTION} Why are ***energy substrates*** added to the cardioplegic solution?

Answer 91

To assist the heart in the production of ATP for energy

Question 92

_{PUMP PRIMING SOLUTION} Prior to its use, why is the bypass pump primed with fluid?

Answer 92

**To get rid of air bubbles** Deairing & priming of pump circuit

Question 93

_{PUMP PRIMING SOLUTION} What is the main cause of hemodilution?

Answer 93

Volume of **Priming Solution** While it attempts to mimic the composition of blood, The increase volume dilutes not only the proteins in the blood, but also plasma levels of drugs

Question 94

_{PUMP PRIMING SOLUTION} What must be considered when choosing a priming solution?

Answer 94

Osmolarity Electrolytes **Pt's preop HCT,** and Overall volume of the circuit

Question 95

_{PUMP PRIMING SOLUTION} The perfusionist must calculate the pt's estimated HCT after the pt's blood is mixed with the priming solution; why?

Answer 95

If dilution is Not anticipated, the pt's depth of anesthesia and circulating drugs may be reduced during bypass ## Footnote *Volume of distribution must be estimated to prevent reduced depths of anesthesia and circulating drug levels*

Question 96

_{PUMP PRIMING SOLUTION} The most commonly used priming solutions are Crystalloids. What are their main benefits?

Answer 96

**Cheaper!!!** **Anaphylactic reactions voided** Easy to handle Improved postoperative pulmonary & renal function

Question 97

_{PUMP PRIMING SOLUTION} What are disadvantages of Crystalloid priming solutions?

Answer 97

Unable to preserve *colloid pressure* This could lead to Post-op **Pulmonary Edema** Addition of *albumin* offsets this

Question 98

_{PUMP PRIMING SOLUTION} What are risks associated with colloid priming solutions?

Answer 98

ALLERGIC REACTIONS Similar effects to albumin ADVERSE EFFECT ON BLOOD COAGULATION Expensive!!!

Question 99

_{PUMP PRIMING SOLUTION} Why would *Heparin* be added to the pump priming solution?

Answer 99

Ensure safety level of anticoagulation

Question 100

_{PUMP PRIMING SOLUTION} Why would Mannitol be added to the pump priming solution?

Answer 100

To Promote diuresis

Question 101

_{PUMP PRIMING SOLUTION} Why would *NaHCO3* be added to the pump priming solution?

Answer 101

(Buffer?!!!)

Question 102

_{PUMP PRIMING SOLUTION} Why would *Antifibrinolytics (Amicar)* be added to the pump priming solution?

Answer 102

Acts as an inhibitor of fibrinolysis

Question 103

_{PUMP PRIMING SOLUTION} Why would *Calcium* be added to the pump priming solution?

Answer 103

To prevent hypocalcemia due to citrate in transfused blood

Question 104

_{PUMP PRIMING SOLUTION} Why would *Corticosteroids* be added to the pump priming solution?

Answer 104

Anti-inflammatory

Question 105

_{PUMP PRIMING SOLUTION} Why would *Blood* be added to the pump priming solution?

Answer 105

If patient is starting off with a low hematocrit

Question 106

_{PUMP PRIMING VOLUME} At the onset of bypass, the pump must be “tested” to ensure that:

Answer 106

It Works!!! Pressures from both the arterial and venous side will be checked

Question 107

_{PUMP PRIMING VOLUME} At the onset of bypass, the pump must be “tested” to ensure that it works. Pressures from both the arterial and venous side will be checked. During that time, the fluid used to prime the machine will then be mixed with:

Answer 107

the patient’s blood

Question 108

_{PUMP PRIMING VOLUME} At the onset of bypass, the pump must “tested” to ensure that it works. Pressures from both the arterial and venous side will be checked. During that time, the fluid used to prime the machine will then be mixed with the patient’s blood, causing:

Answer 108

**Hemodilution** Which reduces blood viscosity in preparation for the hypothermia

Question 109

_{PUMP PRIMING VOLUME} Hemodilution can cause the hematocrit to fall to about which range?

Answer 109

22-27%

Question 110

_{PUMP PRIMING VOLUME} The goal is to maintain a HCT \>

Answer 110

21% ## Footnote *Trend is to maintain HCT \> 21%*

Question 111

_{PUMP PRIMING VOLUME​} While normal hemodilution is tolerated, what is a possible outcome of excessive hemodilution?

Answer 111

Reduce oxygen carrying capabilities

Question 112

_{PUMP PRIMING VOLUME​} What's the average pump priming volume?

Answer 112

1.5 to 2.5 L

Question 113

_{PUMP PRIMING VOLUME​} Some degree of anemia is desirable; why?

Answer 113

Offsets changes in blood viscosity due to hypothermia

Question 114

_{PHYSIOLOGIC EFFECTS OF CPB} What are positive effects of Hypothermia during bypass?

Answer 114

Reduces tissue metabolism & O2 consumption Improves myocardial protection Provides organ protecting during low flow states Provides end-organ protection (liver, brain) in case of low-flow negative effects Reduces anesthetic requirements (↓ awareness)

Question 115

_{PHYSIOLOGIC EFFECTS OF CPB} What are negative effects of Hypothermia during bypass?

Answer 115

Shifts Oxyhemoglobin curve to Left » impairs tissue O2 release Which reduces oxygen delivery to tissue Impairs platelet function and coagulation Reduces serum ionized [Ca2++] ↑ SVR

Question 116

_{PHYSIOLOGIC EFFECTS OF CPB} Shifts Oxyhemoglobin curve to Left » impairs tissue O2 release. This could be Offset by:

Answer 116

↑ O2 solubility at lower temperatures & lower metabolic demands

Question 117

_{PHYSIOLOGIC EFFECTS OF CPB} T/F: While bypass does provide protection to vital organs, it is also a/w some negative side effects

Answer 117

**True**

Question 118

_{PHYSIOLOGIC EFFECTS OF CPB} Many negative physiologic effects of bypass are related to increase in ----- hormone, and -------

Answer 118

**Stress hormone**, and Systemic **inflammatory** responses

Question 119

_{PHYSIOLOGIC EFFECTS OF CPB} The release of these stress hormones can cause:

Answer 119

**Tissue injury**

Question 120

_{PHYSIOLOGIC EFFECTS OF CPB} During bypass, there is an elevated level of circulating catecholamines, cortisol, vasopressin, and angiotensin. Levels of these hormones can be influenced to some degree by:

Answer 120

Depth of anesthesia Type of surgical repair Presence of pulsatility during bypass

Question 121

_{PHYSIOLOGIC EFFECTS OF CPB} What substances are released during a Systemic Inflammatory Response Syndrome (SIRS)?

Answer 121

Endotoxin Tumor necrosis factor Anaphylatoxins Cytokines Neutorphils

Question 122

_{PHYSIOLOGIC EFFECTS OF CPB} What's the physiologic effect of substances released during SIRS?

Answer 122

**Tissue injury** in many organs | (brain, lungs, kidneys, heart)

Question 123

_{PHYSIOLOGIC EFFECTS OF CPB} T/F: supraventricular and ventricular arrhythmias can occur right after bypass and must be immediately treated

Answer 123

True

Question 124

_{PHYSIOLOGIC EFFECTS OF CPB} Usually if patients are in a ventricular arrhythmia, the surgeon will use ---- to defib the heart.

Answer 124

**Internal pads** V-tach and V-fib should be treated immediately =\> internal pads **10-30 J**

Question 125

_{PHYSIOLOGIC EFFECTS OF CPB} What's the most common arrythmia seen around cardiopulmonary bypass?

Answer 125

**Atrial fibrillation** Usually develops 2-5 days postop

Question 126

_{PHYSIOLOGIC EFFECTS OF CPB} How is A-Fib treated in the immediate post-op phase?

Answer 126

**Synchronized cardioversion** Especially if the pt was in sinus rhythm before surgery

Question 127

_{PHYSIOLOGIC EFFECTS OF CPB} What's the drug of choice to treat A-fib caused by CPB?

Answer 127

**Amiodarone**

Question 128

_{PHYSIOLOGIC EFFECTS OF CPB} Metabolic disturbances commonly seen include:

Answer 128

Hypokalemia (_vNa+) Hyperkalemia(^Na+) Hypocalcemia (_vCa2+) Hyperglycemia (^Glucose)

Question 129

_{PHYSIOLOGIC EFFECTS OF CPB} What are causes of Hypokalemia seen during bypass?

Answer 129

Preoperative **diurectics** **Mannitol** administration during bypass Treatment of hyperglycemia with **insulin**

Question 130

_{PHYSIOLOGIC EFFECTS OF CPB} What are causes of Hyperkalemia seen during bypass?

Answer 130

Large doses of **cardioplegia** Impaired **renal** function *Respiratory* or metabolic **acidosis**

Question 131

_{PHYSIOLOGIC EFFECTS OF CPB} What are causes of Hypocalcemia seen during bypass?

Answer 131

Blood transfusion ^(Citrate)

Question 132

_{PHYSIOLOGIC EFFECTS OF CPB} Hyperglycemia is extremely common after bypass. What are its causes?

Answer 132

Use of **glucose-containing cardioplegic** solutions Use of exogenous **catecholamines** Surgical **stress** _{The society of thoracic surgeons recommends keeping glucose levels <180 mg/dl in order to reduce morbidity and mortality associated with hyperglycemia follwing bypass surgery}

Question 133

_{PHYSIOLOGIC EFFECTS OF CPB} Despite heparin reversal, pts oftentimes suffer from bleeding and coagulopathies. Oftentimes, the bleeding is due to:

Answer 133

Inadequate surgical **hemostasis** **Hemodilution** P**latelet dysfunction** **Fibrinolysis**

Question 134

_{PHYSIOLOGIC EFFECTS OF CPB} What are causes of Platelet dysfunction?

Answer 134

Platelet **activation** and **consumption** **Clumping** and **degranulation** after contact with bypass apparatus Reduction in number (**thrombocytopenia**), adhesiveness, and aggregation _{Platelet number and function is often decreased after CPB}

Question 135

_{PHYSIOLOGIC EFFECTS OF CPB} Pulmonary Complications during bypass include:

Answer 135

Atelectasis Decreased arterial oxygenation Bronchospasms Hemo and Pneumothorax Pulmonary Edema

Question 136

_{PHYSIOLOGIC EFFECTS OF CPB} What's a common cause of decreased arterial oxygenation?

Answer 136

**Atelectasis** Can be improved with recrutment maneuvers

Question 137

_{PHYSIOLOGIC EFFECTS OF CPB} Decreased pulmonary blood flow during bypass could lead to:

Answer 137

V/Q mismatch

Question 138

_{PHYSIOLOGIC EFFECTS OF CPB} What's responsible for ↑ PVR (lungs normally inactivate)?

Answer 138

Lack of degradation of catecholamines during CPB Leads to ↑ catecholamines Which results in ↑ PVR (lungs normally inactivate)

Question 139

_{PHYSIOLOGIC EFFECTS OF CPB} Why must the potential for awareness in patients be especially assessed ?

Answer 139

Occurs more frequently in cardiac surgery

Question 140

_{PHYSIOLOGIC EFFECTS OF CPB} Why is the chance of experiencing awareness higher during the rewarming phase?

Answer 140

Hypothermia reduces cerebral metabolic demands *on bypass* This *decreases anesthetic requirements* and awareness Patients have a higher chance of experiencing awareness during the rewarming phase

Question 141

_{PHYSIOLOGIC EFFECTS OF CPB} Awareness is more frequent in cardiac surgery than others; especially during the rewarming phase. Caution should always be used during this time. What could provider do to ease the concern for awareness?

Answer 141

Consider time since last sedative-hypnotic administration Consider administering sedative or hypnotic medication, especially in younger pts

Question 142

_{PHYSIOLOGIC EFFECTS OF CPB} How does CPB affect Renal blood flow and tubular function?

Answer 142

Renal blood flow and tubular function are **decreased** during CPB

Question 143

_{PHYSIOLOGIC EFFECTS OF CPB} T/F: Postoperative renal failure requiring dialysis is common

Answer 143

**False** Postoperative renal failure requiring dialysis is Not common (2-5%)

Question 144

_{PHYSIOLOGIC EFFECTS OF CPB} When Postoperative renal failure requiring dialysis occurs following bypass surgery, which groups are most affected?

Answer 144

The elderly Those with pre-existing renal dysfunction Long duration of bypass Post operative low output syndrome

Question 145

_{PHYSIOLOGIC EFFECTS OF CPB} About what percentage of patients experience one or more complications?

Answer 145

20%

Question 146

_{PHYSIOLOGIC EFFECTS OF CPB} Why is it important to identify patients with a history of renal failure?

Answer 146

For medication metabolism and excretion Could explain hyperkalemia post bypass

Question 147

_{PHYSIOLOGIC EFFECTS OF CPB} What are consequences of Renin-angiotensin-aldosterone system alterations?

Answer 147

Promotes increased renal vascular resistance Promotes Na+ and H20 retention Leads to decreased renal blood flow, GFR, and tubular function

Question 148

_{PHYSIOLOGIC EFFECTS OF CPB} How does Hemodilution protects the kidneys?

Answer 148

Increases **cortical plasma flow**

Question 149

_{PHYSIOLOGIC EFFECTS OF CPB} Hemoglobinuria may result from:

Answer 149

Long bypass runs (\> 4hrs) This could lead to ARF

Question 150

_{PHYSIOLOGIC EFFECTS OF CPB} How does CPB affect cerebral autoregulation values?

Answer 150

CPB is associated with Lowers cerebral autoregulation values

Question 151

_{PHYSIOLOGIC EFFECTS OF CPB} Embolic phenomena during bypass come from:

Answer 151

Fat Thrombi Platelets Foreign substances Air/gas

Question 152

_{PHYSIOLOGIC EFFECTS OF CPB} Why should you keep blood glucose levels \<180 mg/dl?

Answer 152

To prevents **cerebral ischemic** episodes

Question 153

_{PHYSIOLOGIC EFFECTS OF CPB} The *absence* of significant *postoperative morbidity* related to CPB depends primarily on each particular patient’s ability to:

Answer 153

**Compensate** for the physiologic derangements induced by CPB