Flashcards in Pulmonary Response to CPB- Exam 1 Deck (62):
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
What is the most common pulmonary complication?
How common is atelectasis?
What happens when lungs with atelectasis are re-expanded and ventilated?
Variable degree remains (microscopic/lobar)
Atelectasis results in impaired ___________.
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
Atelectasis results in decreased _______________(2).
Atelectasis results in increased _________ (2).
What happens to the alveolar-arterial oxygen gradient in atelectasis?
Factors Contributing to Atelectasis: PREOPERATIVE
Smoking, chronic bronchitis
Cardiogenic pulmonary edema
Factors Contributing to Atelectasis: INTRAOPERATIVE
Anesthesia: reduced surfactant function
Monotonous ventilator pattern
Factors Contributing to Alelectasis: BYPASS
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
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)
What can anesthesia do to prevent atelectasis?
OLC (open lung concept)
Open Lung Concept
a method of ventilation intended to maintain end- expiratory lung volume by increased airway pressure.
When was "Pump Lung" a big problem?
What is "Pump Lung"
Acute respiratory failure
Lungs diffusely congested
Intra-alveolar and interstitial edema
Vessel lumina full of neutrophils
Diffuse swelling of endothelial cells
What might cause acute lung injury?
membrane damage from immune response
decreased pulmonary blood flow
elevated pulmonary artery pressure
What can emboli lead to?
Areas of ventilation/perfusion mismatching
What can cause the ventilation/perfusion mismatching from emboli?
What can greatly reduce degenerative lesions in lungs?
Introduction of arterial and cardiotomy filters
Better the ________-more normal the lungs.
Acute Lung Failure: Membrane Damage
Vasoactive compounds from PMNs
Oxygen free radicals
Ischemia reperfusion injury
Where is complement activation found?
Found wherever blood meets foreign surface
Ex. Hemodialysis, leukophoresis
What functions for fighting invading organisms does complement activation have?
makes bacterial cells vulnerable to phagocytosis by attaching various items
Lungs are ______ from pulmonary circulation during bypass.
(T/F) Lung tissue does not have any metabolic activity on bypass.
False, lung tissue still has metabolic activity
What is the lung metabolic activity on bypass at 36 C?
What is the lung metabolic activity on bypass at 28 C?
5 to 6 ml/min
Is bronchial circulation functional on bypass?
Complement results in ____________(2).
What is our concern with hemodilution?
Decrease in COP
Movement of fluid into the intracellular space
Studies indicate the accumulation of pulmonary extravascular water ________ (is/is not) affected by the type of priming solution.
Does hemodilution harm the lungs?
Hemodilution prevents impairment of ________________.
What is a potential cause of pulmonary edema?
Elevated PA Pressure; due to inadequate venting, increased bronchial blood flow
Elevated PA Pressure can cause
What triggers acute fulminant bronchospasm on bypass?
severe, sudden bronchospasm
What triggers acute bronchospasm on bypass?
Cold urticaria syndrome
Preexisting bronchospastic disease
cold anesthetic gas in patients with hyperactive airways
allergic reactions to antibiotics or protamine
drugs that induce histamine release
What happens with cold urticaria syndrome?
Release histamine when exposed to cold
How do you manage bronchospasm?
Stay on bypass or reinitiate bypass
Rest up to anesthesia
What can anesthesia manage bronchospasm?
Beta selective agonists directly into endotrachial tube (albuterol, metaproterenol)
Small iV bolusis of epi followed by continuous low dose infusion
IV lidocaine given to decrease airway hyperactivity
volatile anesthetic agnets can be given through pump
What does halothane do?
sensitizes myocardium to catecholamines- risk of tachyarrythmias
Prevention and Tx of Acute Lung Injury
proper LV venting
What does Blood filtration do?
Removal of endothelin 1
What do steroids not affect?
C3a activation or leukocyte elastase release
Steroids may inhibit what?
Increase in leukotriene B4 and tissue plasminogen activator
What other problems can steroids cause?
Increased blood loss
low cardiac output syndrome
What may be more protective than corticosteroids?
What do prostaglandins do?
Inhibits intravascular pulmonary leukocyte aggregation, activation, and free radical production
What does aprotinin inhibit?
Serine proteases (plasmin & kallikrein)
Aprotinin prevents the activation of what
Kininogen and formation of bradykinin
What reduces blood usage by preventing platelet aggregation and inhibiting fibrinolysis?
What does aprotinin attenuate?
Bradykinin-induced increases in vascular permeability
Aprotinin results in reduced ________(2) accumulation after bypass.
Endogenous production of what is reduced post CPB
What does inhaled nitric oxide do?
Provides potent vasodilation in the pulmonary vasculature
What is used to treat elevated pulmonary vascular resistance?
Inhaled Nitric oxide