Test 1 content-Pathophysiology of CPB

Question 1

Blood flow to major organs is represented in three ways:

Answer 1

• As a percentage of total flow
• As volume per 100 grams of tissue per min
• As an absolute rate of flow in L/min

Question 2

As metabolic requirements _____ sympathetic tone is ______ resulting in increased cardiac output and oxygen delivery

Answer 2

Increased, Increased

Question 3

Circulatory control during CPB is determined by your _______

Answer 3

Pump flow

Question 4

What 4 things determine pump flow capability?

Answer 4

• Equipment
• Venous return
• Arterial line pressure limits
• Arterial blood pressure

Question 5

Cardiac output is determined by what 4 things?

Answer 5

• Pump flow
• Venous return
• Arterial blood pressure
• Arterial line pressure

Question 6

Goal cardiac output =

Answer 6

Patient’s BSA x Cardiac index

Goal is 2.4 on CPB

Question 7

BP of the patient on CPB influenced by 4 things:

Answer 7

• ANS
• Changes in venous drainage
• Administration of drugs (Vasodilator or vasopressor)
• Largely influenced by the perfusionist

Question 8

Systematic blood flow is guided by 4 things during CPB:

Answer 8

• Patient specifics (age, comorbidities)
• Temp
• Depth of anesthesia
• Hematocrit

Question 9

Max flow rate is determined by 4 things:

Answer 9

• Venous return
• Venous and arterial tubing diameter
• Size of cannulas (venous to allow for adequate drainage, arterial to allow for low enough line pressures)
• Presence of shunts

Question 10

Arterial BP is the product of (2)

Answer 10

Cardiac output and SVR (systemic vascular resistance)

Question 11

SVR is influenced by (6)

Answer 11

• Blood viscosity (Hematocrit and temp)
• Smooth muscle tone in the arterioles
• Depth of anesthesia
• Sympathetic nervous activity
• Acid base status
• Inflammatory mediators

Question 12

Goal for arterial BP in CPB is ______

Answer 12

60 mmHg

Question 13

T/F-Higher perfusion pressures may improve tissue perfusion in higher risk patients?

Answer 13

True

Patients that are older, hypertensive or have peripheral vascular disease are examples

Question 14

Venous pressure is determined by (2):

Answer 14

• Blood volume
• Venous vascular tone (sympathetic nervous system, depth of anesthesia, vasoactive drugs, resistance from venous cannula, gravity drainage vs. vacuum assisted venous return)

Question 15

As pump flow decreases there is progressively _____ organ perfusion

Answer 15

Less

splanchnic, renal and cerebral

Question 16

At the ____1____ of CPB there is a ___2__ in systemic vascular resistance due to viscosity changes and hemodilution

Answer 16

1. Onset

2. Decrease

Question 17

There is _____ SVR during hypothermic CPB

Answer 17

Increased

Question 18

During the rewarming phase of CPB patient response varies due to: (3)

Answer 18

• Anesthesia depth
• Underlying disease
• Hematocrit

Question 19

There are _________ SVR changes as the cross clamp is removed and the heart is re-perfused

Answer 19

More consistant

Question 20

Impaired tissue perfusion and oxygen delivery can lead to: (3)

Answer 20

• Post operative organ dysfunction both temporarily and sometimes permanent
• Variable decreases in oxygen consumption as compared to pre CPB values
• Increases in serum lactate levels

Question 21

Microcirculation function can be impaired by: (4)

Answer 21

• Constriction of pre-capillary arteriolar sphincters
• Edema
• Loss of pulsatile flow
• Sludging in the capillaries in hypothermia

(sludging of blood intravascular agglutination of erythrocytes into irregular masses, interfering with circulation of blood.)

Question 22

The loss of _________ once on CPB is one of the biggest physiological changes

Answer 22

Pulsatile perfusion

Question 23

Roller pumps can mimic _______

Answer 23

Pulsatile perfusion

Question 24

What are the perfusion goals of CPB (5):

Answer 24

• Maintain adequate oxygen delivery to all organs (important to watch cerebral head sats, venous sats, and arterial sats)
• Maintain adequate hematocrit and blood gas values within normal ranges
• Maintain goal BP
• Maintain adequate blood flow (cardiac output)
• Minimize stress response, inflammation, micro embolism and disturbances in the coagulation system

Question 25

Cerebral oximetry is used to monitor the __________

Answer 25

Adequacy of cerebral perfusion

Question 26

__________ is a good indication of hypoperfusion and should be monitored

Answer 26

Metabolic ladctic acidosis

Question 27

Mixed venous oxygen saturation allows us to see how much oxygen the patients body is ________

Answer 27

Extracting.

arterial sats compared to venous sats

Question 28

In line monitoring of ______________ is recommended for all CPB cases

Answer 28

Mixed venous saturation

Question 29

Goal of mixed venous saturation is to maintain an SVO2 of?

Answer 29

> 80%