test 7

Question 1

Normal right ventricle blood return

Answer 1

• systemic venous return
• coronary sinus drainage
• +/- small cardiac vein(s)
• cardioplegia
• thebesian veins

Question 2

Normal left ventricle blood return

Answer 2

• bronchial circulation
• cardioplegia
• thebesian veins

Question 3

Abnormal right ventricle blood return

Answer 3

-persistent left superior vena
cava (LSVC)
-atrial / ventricular septal
defects

Question 4

Abnormal left ventricle blood return

Answer 4

-patent ductus arteriosus (PDA)
-systemic-to-pulmonary artery shunt
-anomalous systemic venous drainage to left heart
-aortic insufficiency
-atrial / ventricular septal
defects

Question 5

bronchial circulation

Answer 5

• provides nutritional flow to lungs
• 1-3% of CO
• can go as high as 10% CO with lung problems
• bronchial veins empty into pulmonary veins

Question 6

small cardiac veins

Answer 6

• usually empty into coronary sinus

- might empty into RA, middle cardiac vein, or never develop

Question 7

Cardioplegia antegrade

Answer 7

• left coronary drains into coronary sinus and the right atrium
• right coronary drains into RA by small cardiac veins
• some flow return to all chambers by thebesian veins

Question 8

cardioplegia retrograde

Answer 8

• most empties into artic root via left coronary ostia

- really bad job of protecting the heart

Question 9

Persistent left superior vena cava

Answer 9

• normally drains into right coronary sinus

- occurence: 0.3% to 0.5% of general population and 2-10% of patients with congenital heart disease

Question 10

problems associated with LSVC

Answer 10

• procedures requiring opening of right heart and use of bicaval cannulation with tapes
• delivery of retrograde cardioplegia: proper position of balloon in coronary sinus, delivery of solution up LSVC rather than coronary sinus, and dilution of solution by LSVC return

Question 11

LSVC results from

Answer 11

1) Failure of the L. brachiocephalic vein to fully develop

2) Failure of the left common cardinal vein to disappear during development

Question 12

systemic to pulmonary artery shunts

Answer 12

• Blalock-Taussig shunt= transected right subclavian artery connected to right pulmonary artery
• Waterston= posterior ascending aorta connected to anterior right pulmonary artery

Question 13

aortic insufficiency

Answer 13

-Not a problem as long as heart beating
-Placement of cross-clamp stops regurgitation
from arterial cannula
-Can occur during cardioplegia delivery: indicated by low delivery pressure into aortic root
-Can result in significant left ventricular
distension in fibrillating or arrested heart

Question 14

Ventricular venting: purpose

Answer 14

-Prevent ventricular distension (and all the “bad” that
goes with it!)
-Improve surgical exposure
-Aid in myocardial protection
-Remove air
-Prevent pulmonary venous hypertension

Question 15

myocardial protection by decompression

Answer 15

-Accounts for approximately 40% of myocardial protection
-Reduces wall tension and myocardial stretch – reduces RESTING oxygen
consumption

Question 16

myocardial protection by increased subendocardial perfusion

Answer 16

-Normal coronary perfusion pressure (CPP) = mean arterial (MAP) minus left
ventricular end diastolic (LVEDP)
-With cross-clamp applied and antegrade delivery of cardioplegia CPP = aortic root pressure – LVEDP
-with left ventricle empty LV coronary perfusion is optimal

Question 17

myocardial protection by preventing myocardial rewarming

Answer 17

• Hypothermia accounts for approximately 10% of myocardial protection
• By removing systemic return to heart, heart stays cool

Question 18

air removal

Answer 18

-Large quantities may arise during intracardiac
operations
-Venting aids de-airing upon closure of incision
into heart but before cross-clamp removal
-Small amounts may be introduced during
coronary bypass procedures

Question 19

concerns with venous cannulation and blood return

Answer 19

• Venous cannulation must collect all return from: superior vena cava, inferior vena cava, coronary sinus
• Bicaval cannulation with snares/tapes- cannot collect coronary sinus return
• Improper placement of cannula
• Inadequate cannula size
• Inadequate height (siphon) gradient (∆P)

Question 20

vent locations

Answer 20

• aortic root
• right superior pulmonary vein
• main pulmonary artery
• apex of left ventricle: very dangerous (not used much to at all anymore)

Question 21

venting aortic root description

Answer 21

-Small bore catheter direct into the aorta
-May be wyed into catheter along with antegrade cardioplegia
delivery line

Question 22

venting Right superior pulmonary vena cava description

Answer 22

-Can be Advanced across mitral valve into LV or left in LA

Question 23

venting Main pulmonary artery description

Answer 23

-Tends to interfere with the pulmonary artery monitoring catheter

Question 24

venting Apex of left ventricle description

Answer 24

-Problems associated with direct cannulation of the left ventricle
-Surgeon may insert a 27 gauge needle into apex for temporary
use to remove air stuck in the apical area

Question 25

Root vent with antegrade cardioplegia needle

Answer 25

- Vent must be off during cardioplegia delivery - Able to remove some air in the ascending aorta prior to cross-clamp removal or even as air is ejected from the left ventricle (remember, air rises and the aorta’s a tube…)

Question 26

Left ventricular vent

Answer 26

Pliable with multiple fenestrations (openings) to aid blood removal and limit risk of sucking tissue into catheter

Question 27

mechanical drainage

Answer 27

-Via roller pump -Always best to include one-way valve in return line to minimize chance of pump air into heart Can use higher pump RPMs if: -Use a vacuum relief valve – opens if too much vacuum applied – prevents pulling ventricular tissue into catheter tip = “Endocardial hickies” (can be part of one-way valve or separate) -Must use low pump RPMs if no relief value used -Best to monitor LA pressure -Always a good idea to “run your CP to your vent” ahead of time because you don't want to send bubbles to aorta

Question 28

gravity drainage: “Y’ vent line into venous return line

Answer 28

Venous return blood passing opening of wye connector creates Venturi Effect - Usually done at the table – shorter line with less resistance to flow - Vent line needs to be primed to reduce chance of venous air lock - Surgeon controls vent (on versus off) at field)

Question 29

gravity drainage: normal vent line

Answer 29

-Procedure: fill vent line with couple turns of roller pump and remove line from pump to allow gravity pressure gradient to move fluid from heart to the reservoir -May not adequately drain heart if large amounts of return -May need to use larger bore tubing for vent line

Question 30

cardiotomy/ pump suction

Answer 30

-Blood from the field that is returned to the CPB circuit during bypass, or an autotransfusion reservoir pre- and post-CPB -Large amount of air-blood interface can will lead to hemolysis and potential micro air emboli: Use of separate cardiotomy filter has been shown to reduce # of air emboli.

Question 31

blood collected in chest

Answer 31

- typically has elevated concentrations of activated humoral elements including”: Coagulation factors (tissue factor), Endotoxin, Complement, Interleukins -Profound drop in arterial blood pressure often seen when cardiotomy suction blood is directly infused into patient

Question 32

cardiotomy suction using cell saver

Answer 32

- Reduction in post-operative bleeding when stagnant chest blood is washed and filtered prior to reinfusion - Reduction in cerebral fat emboli and stroke rate by eliminating chest blood return via pump suckers

Question 33

cell saver guidlines

Answer 33

-Use collection reservoir with a built-in 40 to 150 micron filter -Vacuum attached to collection reservoir should not exceed -120 mmHg -An anticoagulant drip must be used -Washed product should be returned to the patient through a transfusion filter -Collected cells should be washed with AT LEAST 1,000 mLs of normal saline – wash effluent should be clear -Washed product must be transferred to a separate reinfusion bag (reduce chance of air emoli) -don't use pressure bag to speed reinfusion time

Question 34

Reinfusion bag should be properly labeled with four | things:

Answer 34

1) Patient name and ID#; 2) Expiration time (6 hours from collection time at room temperature); 3) Volume in bag; 4) Note stating “Autologous Use Only”

Question 35

quarterly testing should check

Answer 35

- Product hematocrit greater than 40% - Product potassium less than 3.0 mEq/L - Product free hemoglobin concentration less than 100 mg/dL - Product heparin concentration less than 0.5 units per ml

Question 36

summary

Answer 36

- Use of vent and pump suction should be minimal amount needed to expose operative field and protect the myocardium - Use of cell saver device in lieu of pump suction for pooled and/or stagnant blood