3. Pulmonary Response- Exam 1 Flashcards
define 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
Atelectasis is the most common pulmonary complication by what %
70%
what are the 2 variables of degree of Atelectasis that remains when lungs are re-expanded and ventilated
microscopic
lobar
ATELECTASIS decreases functional residual capacity by ___% after general anesthesia
20%
ATELECTASIS decreases functional residual capacity ___% after CPB
40-50%
ATELECTASIS impares oxygenation by what 4 things
decreased functional residual capacity
decreased lung compliance
increased veno-arterial admixture
Alveolar-arterial oxygen gradient –P(A-a)O2 increases
what 3 risk-factors contribute to pre-op atelectasis
smoking, chronic bronchitis
obesity
cardiogenic pulmonary edema
what 3 risk-factors contribute to intra-op atelectasis
anesthesia: reduced surfactant function
passive ventilation
monotonous ventilator pattern
what 5 risk-factors contribute to CPB atelectasis
surfactant inhibition plasma, lung distention, lung ischemia increased extravascular lung water heart rests on immobile left lower lobe open pleural cavity – accumulation of blood and fluid
WHAT CAN WE DO TO PREVENT ATELECTASIS?
Decrease complement activation
Reduce chances of edema
Anesthesia has more control (PEEP, CPAP, OLC)
describe 1950’s “Pump Lung”: acute respiratory failure (5)
lungs diffusely congested intra-alveolar and interstitial edema hemorrhagic atelectasis vessel lumina full of neutrophils diffuse swelling of endothelial cells
WHAT 5 things MIGHT CAUSE ACUTE LUNG INJURY?
Embolic load Membrane damage from immune response Decreased pulmonary blood flow Hemodilution Elevated pulmonary artery pressure
Emboli can lead to areas of ventilation/perfusion mismatching. What 5 things can cause this?
aggregated proteins disintegrated platelets damaged neutrophils fibrin fat globules
Introduction of what greatly reduced degenerative lesions in lung
arterial and cardiotomy filters
Better the filtration – more normal the lungs
Complement Activation is Found wherever blood meets foreign surface. Give 2 examples
hemodialysis
leukophoresis
Complement Activation Provides several functions for fighting invading organisms. Give 3 examples
- leukocyte activation
- cytolysis
- opsonization (makes bacterial cells vulnerable to phagocytosis by attaching various items)
what 4 things can cause membrane damage in acute lung failure
Complement Activation
Vasoactive compounds from PMNs
Oxygen free radicals
Ischemia reperfusion injury
Even though the Lungs are isolated from pulmonary circulation during bypass, Lung tissue still has metabolic activity. What is it at 36C and 28C
11 mL/minute at 36 oC
5 to 6 mL/minute at 28 oC
Is Bronchial circulation still functional during CPB
yes
why is hemodilution a concern
Concerned with decrease in colloid osmotic pressure and movement of fluid into the intracellular space
Studies seem to indicate the accumulation of pulmonary extravascular water is not affected by what?
the type of priming solution
Hemodilution does not appear to harm the lungs, it actually prevents impairment of what?
surfactant
Potential cause of pulmonary edema due to what 2 things
Inadequate venting
Increased bronchial blood flow
what can cause ELEVATED PA PRESSURE
pulmonary edema
complement activation
how often does ACUTE BRONCHOSPASM DURING BYPASS occur
rare
ACUTE BRONCHOSPASM DURING BYPASS can be triggered by what (8)
- activation C5a (fulminant bronchospasm)
- cold urticaria syndrome (release histamine when exposed to cold)
- preexisting bronchospastic disease
- instrumentation
- secretions
- cold anesthetic gas in patients with hyperactive airways
- allergic reactions to antibiotics or protamine
- drugs that induce histamine release
how do you manage bronchospasm during bypass
Stay on bypass or reinitiate bypass
Rest up to anesthesia
management bronchospasm: administration of beta selective agonists directly into endotracheal tube. Give 2 examples
albuterol, metaproterenol
management bronchospasm: small IV boluses of _____ followed by continuous low-dose infusion
epinephrine
management bronchospasm: why is IV lidocaine given
to decrease airway hyperactivity
management bronchospasm: volatile anesthetic agents can be given through pump. Give 2 examples
- potent bronchodilators
2. halothane sensitizes myocardium to catecholamines – risk of tachyarrhythmias
name 9 things you can do for PREVENTION & TREATMENT OF ACUTE LUNG INJURY
- Blood filtration
- Coated circuits
- Membrane oxygenators
- Hemodilution- avoid homologous blood primes
- Proper LV venting
- Steroids
- Prostaglandins
- Aprotinin
- Inhaled Nitric Oxide
steroids do not effect what
does not affect C3a activation or leukocyte elastase release
steroids may inhibit what
may inhibit increase in leukotriene B4 and tissue plasminogen activator
what other problems can steroids cause
increased blood loss
low cardiac output syndrome
give 2 examples of what you would use for blood filtration
leukocyte depletion, removal of endothelin-1
Prostaglandins may be more protective than what?
corticosteroids
Prostaglandins inhibit what?
intravascular pulmonary leukocyte aggregation, activation, and free radical production
Prostaglandins need to be careful because of?
hypotensive effect
Aprotinin inhibits what?
serine proteases (plasmin & kallikrein)
Aprotinin prevents what?
the activation of kininogen and formation of bradykinin
Aprotinin definitely reduces blood usage by doing what?
preventing platelet aggregation and inhibiting fibrinolysis
Aprotinin attenuates what?
bradykinin-induced increases in vascular permeability
Aprotinin reduces what?
lung neutrophil accumulation after bypass
Inhaled Nitric Oxide- Endogenous production is reduced post CPB… this Potentiates what?
pulmonary hypertension
Inhaled Nitric Oxide Provides what?
potent vasodilation in the pulmonary vasculature
Inhaled Nitric Oxide Used to treat what?
elevated pulmonary vascular resistance
Inhaled Nitric Oxide has Some anti-inflammatory properties such as
Decreases IL-8
Attenuates neutrophil adhesion and migration
Attenuates apoptosis in lungs
