Pulmonary Response to CPB- Exam 1 Flashcards Preview

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1

Atelectasis

A complete or partial collapse of a lung or a lobe of the lung; develops when the alveoli become deflated and don't inflate properly

2

What is the most common pulmonary complication?

Atelectasis

3

How common is atelectasis?

70%

4

What happens when lungs with atelectasis are re-expanded and ventilated?

Variable degree remains (microscopic/lobar)

5

Atelectasis results in impaired ___________.

Oxygenation

6

Atelectasis results in decreased ______________(3). What percent after anesthesia? What percent after CPB?

Functional Residual Capacity; decreased by 20% after general anesthesia, by 40-50% after CPB

7

Atelectasis results in decreased _______________(2).

Lung compliance

8

Atelectasis results in increased _________ (2).

Veno-arterial admixure

9

What happens to the alveolar-arterial oxygen gradient in atelectasis?

P(A-a)O2 increases

10

Factors Contributing to Atelectasis: PREOPERATIVE

Smoking, chronic bronchitis
Obesity
Cardiogenic pulmonary edema

11

Factors Contributing to Atelectasis: INTRAOPERATIVE

Anesthesia: reduced surfactant function
passive ventilation
Monotonous ventilator pattern

12

Factors Contributing to Alelectasis: BYPASS

Surfactant inhibition
Plasma, lung distention, lung ischemia
Increased extravascular lung water ( complement activation)
heart rests on immobile left lower lobe
Open pleural cavity- accumulation of blood and fluid

13

What can we do to prevent atelectasis?

Decreased complement activation
Reduced chances of edema
Anesthesia has more control (i.e. how lungs are deflated and re-inflated)

14

What can anesthesia do to prevent atelectasis?

PEEP
CPAP
OLC (open lung concept)

15

Open Lung Concept

a method of ventilation intended to maintain end- expiratory lung volume by increased airway pressure.

16

When was "Pump Lung" a big problem?

1950's

17

What is "Pump Lung"

Acute respiratory failure
Lungs diffusely congested
Intra-alveolar and interstitial edema
Hemorrhagic atelectasis
Vessel lumina full of neutrophils
Diffuse swelling of endothelial cells

18

What might cause acute lung injury?

Embolic load
membrane damage from immune response
decreased pulmonary blood flow
hemodilution
elevated pulmonary artery pressure

19

What can emboli lead to?

Areas of ventilation/perfusion mismatching

20

What can cause the ventilation/perfusion mismatching from emboli?

Aggregated proteins
Disintegrated platelets
Damaged neutrophils
Fibrin
Fat Globules

21

What can greatly reduce degenerative lesions in lungs?

Introduction of arterial and cardiotomy filters

22

Better the ________-more normal the lungs.

Filtration

23

Acute Lung Failure: Membrane Damage

Complement Activation
Vasoactive compounds from PMNs
Oxygen free radicals
Ischemia reperfusion injury

24

Where is complement activation found?

Found wherever blood meets foreign surface
Ex. Hemodialysis, leukophoresis

25

What functions for fighting invading organisms does complement activation have?

Leukocyte activation
Cytolysis
Opsonization

26

Opsonization

makes bacterial cells vulnerable to phagocytosis by attaching various items

27

Lungs are ______ from pulmonary circulation during bypass.

Isolated

28

(T/F) Lung tissue does not have any metabolic activity on bypass.

False, lung tissue still has metabolic activity

29

What is the lung metabolic activity on bypass at 36 C?

11/ ml/min

30

What is the lung metabolic activity on bypass at 28 C?

5 to 6 ml/min