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253-Green Patho > Respiratory- Ventilation > Flashcards

Flashcards in Respiratory- Ventilation Deck (27):

What is Asthma?

What characterizes an episode?

•Reversible episodes of airway obstr d/t inflm r/t smooth muscle hyperactivity brought on by a trigger.


Basic etiology of Asthma

Complex trait (genetics and Enviro)


What are common triggers or stimuli of hypersensitivity in Asthma?

Airway irritants
Strong odours
Cold air (more often secondary trigger)


What are the two phases of Response

Early (acute) Phase: Mast cell degranulation, infiltration of inflm cells, release inflm mediators leading to bronchospasm

Late Phase: Air inflm leading to de, impaired mucocilliary fx and epithelial injury. Can inc air responsiveness and also cause bronchospasm


Describe the Patho of early response Asthma

• Prior sensitization to allergen (Type 1 HS)
• Subseq exposure -> allergen binds to IgE coated mast cells -> mediator release -> inflm
• Intercellular junctions open ->allergens enter submucosa
• Inc permeability and inc mucous secretion -> edema of airways
• PNS stimulated bronchospasm
• Dyspnea and wheezing
• Airway constriction (compensatory)
• Lasts up to an hour, Normally begins within a few minutes


Describe the Patho of late response Asthma

Timing and Changes in Airway

• Peaks in 4-8hr
• Mnfts of acute phase persist
• Self sustaining cycle of exarcebation
• Can last days to weeks
• Influx of inflm of cells
o Epithelial damage
o Dec mucociliary Fx
o Hyperresponsive airway
• Respond to new triggers (eg cold air)
• Frequent and severe episode


What is mediating late response Asthma

• Bronchoconstriction via alpha adrenergic receptors
• Bronchodilator via B adrenergic receptors
• cAMP mediates (related to hormone action)
• THe theory: Lack of B receptor stimulation in asthma?


MNFTS of Asthma

• Dyspnea
• Wheezing
• Immobilization?
• Bronchospasm and Coughing
• Inc resp effort
• Ventilatory compromise (alt resp status and ABG’s)


DX of Asthma

• Hx, Px
• Labs
• Pulm fx tests
• Inhalation challenge tests
o Exposing pt to potential allergens to explore sensitivities


Basics of Asthma Tx (not specific pharma)

• Control with minimal meds
• Prophylactic tx has become more popular
• Preventative:
o Avoid allergens and irritants
o No smoking


Steps in Pharma Tx of Asthma

o Step 1: inhaled short acting bronchodilators
o Step 2: add inhaled steroids
o Step 3: add long term bronchodilators
o Step 4:
• Short course steroids
• Add third drug –leukotriene (mediator) receptor antagonist or theophylline


What is Atelectasis?

Collapse of part of the lung -> impedes filing
Affected part of lung becomes non fx


Describe 3 Types of Atelectasis

• Obstructive/Resorptive Atelectasis
o a/w obstr (eg by mucous) -> air trapped -> absorbed into capillaries -> local collapse

• Compression Atelectasis
o Ext pressure on lungs (eg tumor)

• Contraction
o Scar tissue contraction -> lung collapse


MNFTS of Atelectasis

• Dyspnea
• Tachypnea (inc rate provides some inc in volume (per time)
• Dec chest expansion
• Tachycardia (compensatory)


Dx of Atelectasis

• Px
• CXR (pick up most except smallest cases)
• CT
• Bronchoscopy


Tx Atelectasis

• Cause (Identify and treat)
• Resp support


What is a Pleural effusion


ACCUMULATION of fluid in the pleural space

(AKA Hydrothorax)


What is the simplify reason for fluid accumulation in the pleural space?

(i.e. What is it due to?)j

d/t abn seepage (from circulation) &;/or drainage (to circulation)


Describe 5 kinds of fluid that might be accumulating in a pleural effusion.

(each has medical term)

o exudate: inflm fluid, inc protein content
o transudate: non inflm fluid, dec protein content
o empyema: purulent
o hemothorax: blood
o Chylothorax: lymph


Common causes of pleural effusion?

• Usually CHF
• Infect, Ca, Pulm Infarction


Patho of pleural effusion

What is pleural effusion similar to?

• Fluid enters via parietal caps
• Drains into parietal lymphatics
• Fluid entry exceeds drainage ->pleural effusion

Note: Similar to cardiac taponade


MNFTS of Pleural effusion?

• Based on cause and volume
o Dyspnea
o Pleuritic pain (membrane stretch d/t pressure, depends on volume)
o Lung compression (prior to expansion)


Dx of Pleural effusion

• X-ray
• US
• CT


Tx of Pleural Effusion

• Cause (identify and treat)
• Thoracentesis (+fluid analysis)
• Chest tube?


What is dead airspace?

volume that is moved with each breath that does not participate in gas exchange.
(Reflects a mismatch of ventilation and perfusion)


What is a shunt? (in reference to pulmonary system)

When blood moves from venous to arterial circulation without being oxygenated.

(Reflects a mismatch of ventilation and perfusion)


Why does 02 move from Alveolus into the capillaries ?

Works on concentration gradient (P02 is higher in the lung then in the capillary)