Respiratory- Ventilation

Question 1

What is Asthma?

What characterizes an episode?

Answer 1

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

Question 2

Basic etiology of Asthma

Answer 2

Complex trait (genetics and Enviro)

Question 3

What are common triggers or stimuli of hypersensitivity in Asthma?

Answer 3

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

Question 4

What are the two phases of Response

Answer 4

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

Question 5

Describe the Patho of early response Asthma

Answer 5

• 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

Question 6

Describe the Patho of late response Asthma

Timing and Changes in Airway

Answer 6

•	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

Question 7

What is mediating late response Asthma

Answer 7

• 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?

Question 8

MNFTS of Asthma

Answer 8

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

Question 9

DX of Asthma

Answer 9

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

Question 10

Basics of Asthma Tx (not specific pharma)

Answer 10

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

Question 11

Steps in Pharma Tx of Asthma

Answer 11

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

Question 12

What is Atelectasis?

Answer 12

Collapse of part of the lung -> impedes filing

Affected part of lung becomes non fx

Question 13

Describe 3 Types of Atelectasis

Answer 13

• 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

Question 14

MNFTS of Atelectasis

Answer 14

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

Question 15

Dx of Atelectasis

Answer 15

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

Question 16

Tx Atelectasis

Answer 16

• Cause (Identify and treat)

* Resp support

Question 17

What is a Pleural effusion

AKA?

Answer 17

ACCUMULATION of fluid in the pleural space

AKA Hydrothorax

Question 18

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

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

Answer 18

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

Question 19

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

(each has medical term)

Answer 19

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

Question 20

Common causes of pleural effusion?

Answer 20

• Usually CHF

* Infect, Ca, Pulm Infarction

Question 21

Patho of pleural effusion

What is pleural effusion similar to?

Answer 21

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

Note: Similar to cardiac taponade

Question 22

MNFTS of Pleural effusion?

Answer 22

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

Question 23

Dx of Pleural effusion

Answer 23

• X-ray
• US
• CT

Question 24

Tx of Pleural Effusion

Answer 24

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

Question 25

What is dead airspace?

Answer 25

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

Question 26

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

Answer 26

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

(Reflects a mismatch of ventilation and perfusion)

Question 27

Why does 02 move from Alveolus into the capillaries ?

Answer 27

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