Test 1 content-Pathophysiology of CPB Flashcards Preview

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Flashcards in Test 1 content-Pathophysiology of CPB Deck (29)
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1

Blood flow to major organs is represented in three ways:

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

2

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

Increased, Increased

3

Circulatory control during CPB is determined by your _______

Pump flow

4

What 4 things determine pump flow capability?

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

5

Cardiac output is determined by what 4 things?

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

6

Goal cardiac output =

Patient's BSA x Cardiac index

(Goal is 2.4 on CPB)

7

BP of the patient on CPB influenced by 4 things:

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

8

Systematic blood flow is guided by 4 things during CPB:

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

9

Max flow rate is determined by 4 things:

*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

10

Arterial BP is the product of (2)

Cardiac output and SVR (systemic vascular resistance)

11

SVR is influenced by (6)

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

12

Goal for arterial BP in CPB is ______

60 mmHg

13

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

True

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

14

Venous pressure is determined by (2):

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

15

As pump flow decreases there is progressively _____ organ perfusion

Less

(splanchnic, renal and cerebral)

16

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

1. Onset

2. Decrease

17

There is _____ SVR during hypothermic CPB

Increased

18

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

*Anesthesia depth
*Underlying disease
*Hematocrit

19

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

More consistant

20

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

*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

21

Microcirculation function can be impaired by: (4)

*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.)

22

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

Pulsatile perfusion

23

Roller pumps can mimic _______

Pulsatile perfusion

24

What are the perfusion goals of CPB (5):

*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

25

Cerebral oximetry is used to monitor the __________

Adequacy of cerebral perfusion

26

__________ is a good indication of hypoperfusion and should be monitored

Metabolic ladctic acidosis

27

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

Extracting.

(arterial sats compared to venous sats)

28

In line monitoring of ______________ is recommended for all CPB cases

Mixed venous saturation

29

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

>80%