Test 6

Question 1

Venous drainage from superior vena cava

Answer 1

1/3

Question 2

Venous drainage from inferior vena cava

Answer 2

2/3

-more veins under the heart allowing for more drainage

Question 3

Types of venous drainage

Answer 3

• achieved by gravity- pressure differential between patient and top of reservoir
• augmented- when gravity alone does not provide adequate drainage requiring a vacuum or kenetic assist (centrifugal)

Question 4

Siphon Drainage (Gravity)

Answer 4

• Venous reservoir must be below patient
• venous lines must be filled with fluid
• amount of drainage depends on: Central venous pressure, distance from patient to blood level in venous reservoir, and resistance created by cannula, connectors, and venous line
• siphon gradient of 30-40 mmHg is normal

Question 5

Venous cannula made of/look like

Answer 5

• flexible plastic
• single stage or two stage
• straight or right angled
• wire reinforced to prevent kinking
• tip plastic or metal

Question 6

Cannula size based on

Answer 6

patient’s weight and BSA

Question 7

Limiting factor of venous drainage because

Answer 7

narrowest component of CPB venous system

Question 8

site for venous cannulation

Answer 8

• single cannulation of the right atrium
• bicaval cannulation of the SVC and IVC (mitral valve repair)
• Dual stage cannulation of atrium and IVC (most common)(CABG)
• femoral vein cannulation (reoperations)

Question 9

two-stage venous cannulation

Answer 9

• single cannula inserted into right atrium through the right atrial appendage
• narrow tip of cannula sits in IVC which drains the vein
• can’t have total pulmonary bypass
• wider portion sits in the RA where it receives blood rom coronary sinus and SVC

Question 10

Advantages of two-stage cannulation

Answer 10

• simple
• fast
• good right heart decompression
• less traumatic

Question 11

Disadvantages of two-stage cannulation

Answer 11

• very sensitive to positioning especially when heart is lifted
• leads to poor drainage

Question 12

process of two-stage cannulation

Answer 12

1. Venous cannula placed after insertion of atrial cannula
2. purse string sutures in RA appendage
3. Cut tip of RA appendage
4. insert venous cannula
5. tighten purse string
6. fill cannula with fluid
7. connect cannula to pump lines
8. clamp tubing to drapes

Question 13

bicaval venous cannulation

Answer 13

• separate cannulation of SVC and IVC
• incision through RA or directly in vena cava
• caval tapes often used which forces all venous return of patient to pass to ECC
• caval occlusion is called “total bypass”

Question 14

Advantages of bicaval venous cannulation

Answer 14

• good caval drainage
• best myocardial protection
• complete right heart exclusion

Question 15

Disadvantages of bicaval venous cannulation

Answer 15

• slower speed of cannulation
• technically more difficult
• poor right heart decompression when heart lifted

Question 16

Femoral venous cannulation

Answer 16

• used for emergency CPB
• reoperations
• minimally invasive surgeries

Question 17

When using femoral cannulation

Answer 17

• want larges cannula as possible
• inserted with the aid of transesopageal echo (TEE)
• most likely need vacuum or kenetic assist

Question 18

impact of Persistent Left Superior Vena Cava (LSVC)

Answer 18

• .3-.5% of population

- 2-10% of patients with congenital heart disease

Question 19

Left superior vena cava (LSVC)

Answer 19

• usually drain into the coronary sinus then into RA
• suspected when there is a large coronary sinus
• Sometimes can be seen in echocardiagraphy

Question 20

Problems associated with LSVC

Answer 20

• complicate passage of PA catheter
• interfere with administration of retrograde cardioplegia because balloon on catheter does not seal then leaks into RA
• if bicaval cannulation used problems with right heart decompression and venous return due to additional system venous blool into RA in which the surgeon can occlude or cannulate LSVC to solve

Question 21

Complications achieving venous drainage

Answer 21

• atrial dysrhythmias
• laceration of atrium
• bleeding of atrium
• laceration of vena cava
• malposition of cannula tips
• displacement of PA catheter

Question 22

Causes of low venous return

Answer 22

• reduced venous pressure (hypovolemia or drugs causing venodilation)
• malposition of cannulas
• kinks in venous line
• clamps on venous line
• air lock
• cannulas too small

Question 23

Venous chatter

Answer 23

• catheter draining too efficiently
• drainage holes become obsructed by RA tissue
• causes sporadic changes in venous flow
• difficult to sew, heart is moving

Question 24

remedies for venous chatter

Answer 24

• decrease height gradient
• partially occlude venous line
• decrease vacuum

Question 25

What surgeon wants

Answer 25

• clear, easily visible operative field (exposure)
• small cannula
• no physiological problems from not enough venous return (increased CVP(central venous pressure)/ volume overload

Question 26

what perfusionists want

Answer 26

• large cannula
• good flow dynamics
• lots of volume draining to the reservoir
• no air

Question 27

performance of venous cannula depends on

Answer 27

• size
• design
• proper placement
• ability to drain (gravity or vacuum)