Flashcards in Pulmonary Response to CPB- Exam 1 Deck (62)
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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
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What is the most common pulmonary complication?
Atelectasis
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How common is atelectasis?
70%
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What happens when lungs with atelectasis are re-expanded and ventilated?
Variable degree remains (microscopic/lobar)
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Atelectasis results in impaired ___________.
Oxygenation
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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
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Atelectasis results in decreased _______________(2).
Lung compliance
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Atelectasis results in increased _________ (2).
Veno-arterial admixure
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What happens to the alveolar-arterial oxygen gradient in atelectasis?
P(A-a)O2 increases
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Factors Contributing to Atelectasis: PREOPERATIVE
Smoking, chronic bronchitis
Obesity
Cardiogenic pulmonary edema
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Factors Contributing to Atelectasis: INTRAOPERATIVE
Anesthesia: reduced surfactant function
passive ventilation
Monotonous ventilator pattern
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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
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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)
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What can anesthesia do to prevent atelectasis?
PEEP
CPAP
OLC (open lung concept)
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Open Lung Concept
a method of ventilation intended to maintain end- expiratory lung volume by increased airway pressure.
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When was "Pump Lung" a big problem?
1950's
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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
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What might cause acute lung injury?
Embolic load
membrane damage from immune response
decreased pulmonary blood flow
hemodilution
elevated pulmonary artery pressure
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What can emboli lead to?
Areas of ventilation/perfusion mismatching
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What can cause the ventilation/perfusion mismatching from emboli?
Aggregated proteins
Disintegrated platelets
Damaged neutrophils
Fibrin
Fat Globules
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What can greatly reduce degenerative lesions in lungs?
Introduction of arterial and cardiotomy filters
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Better the ________-more normal the lungs.
Filtration
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Acute Lung Failure: Membrane Damage
Complement Activation
Vasoactive compounds from PMNs
Oxygen free radicals
Ischemia reperfusion injury
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Where is complement activation found?
Found wherever blood meets foreign surface
Ex. Hemodialysis, leukophoresis
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What functions for fighting invading organisms does complement activation have?
Leukocyte activation
Cytolysis
Opsonization
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Opsonization
makes bacterial cells vulnerable to phagocytosis by attaching various items
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Lungs are ______ from pulmonary circulation during bypass.
Isolated
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(T/F) Lung tissue does not have any metabolic activity on bypass.
False, lung tissue still has metabolic activity
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What is the lung metabolic activity on bypass at 36 C?
11/ ml/min
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