Pathology Exam-respiratory Failure

Question 1

What is pulmonary perfusion?

Answer 1

Amount of blood reaching alveoli

Question 2

What is the ventilation/perfusion ratio?

Answer 2

The ratio between amount of air reaching the alveoli and amount of blood rewatching the alveoli

• alveolar ventilation/cardiac output
• assesses the efficiency and adequacy by matching the two variables
• adequate is V/Q= 0,8

Question 3

How do you asses V/Q ratio?

Answer 3

V/Q= 0,8 is healthy
V/Q= more than 0,8 is proper ventilation;hypoperfusion
V/Q= less than 0,8 is alveolar hypoventilation; correct perfusion

Question 4

What is respiratory insufficiency?

Answer 4

Inability of adequate gas exchange btw blood-lungs
Consequences:
-Hypoxemia and/or hypercapnia
- hypoxemia+hypercapnia= total RI
- only hypoxemia= partial RI

Question 5

What is obstructive lung disease?

Answer 5

Airway obstruction
- bronchitis
- tracheal collapse
- foreign body
Leads to bradypnea and emphysema

Question 6

What is restrictive lung disease?

Answer 6

Lowered ability for lungs to expand

• insufficient contraction of respiratory muscles (nm disease, pain)
• increased resistance in lung expansion (pleural disease, abnormalities)
• pulmonary disease affecting elasticity

Question 7

What is intrapulmonary vs extrapulmonary restrictive respiratory insufficiency?

Answer 7

Intrapulmonary:
- edema, interstitial pneumonia, alveolar fibrosis
- reduces elasticity
Extrapulmonary:
- pulmonary compression, pleural effusion, pneumothorax, tumours
- reduces ventilation
- normal perfusion

Question 8

What are the types of hypoxia?

Answer 8

Hypoxic= inadequate blood oxygen saturation
Anemic= reduced capacity of blood to carry oxygen
Circulatory/stagnant= decrease in blood flow
Histotoxic= inability of tissue/cells to absorb oxygen

Question 9

What is hypoxic hypoxia?

Answer 9

Due to:

• high altitude
• respiratory failure
• blend of arterial-venous blood (shunt)

Question 10

What are the compensatory mechanisms of hypoxia?

Answer 10

• Hyperventilation
• polycythemia
• shifted blood flow
• production of 2,3 DPG
• circulatory= increased cardiac output

Question 11

What is cyanosis?

Answer 11

Bluish coloration of skin/mucous membranes

• due to deoxyhemoglobin by deoxygenation
• when arterial saturation is less than 80%
• 5,0 g/dL or more in blood
• not synonymous with hypoxia

Question 12

What are causes of cyanosis?

Answer 12

Central cyanosis:
- low oxygen in blood
- circulatory or respiratory failure= poor oxygenation in lungs
Peripheral cyanosis:
-cold exposure
- venous obstruction
Other:
-methaemoglobinemia

Question 13

What is hypercapnia?

Answer 13

Abnormally elevated CO2 levels in blood
-due to respiratory failure or rebreathing system
-leads to acidosis
Consequences:
-Hyperventilation
-central vasoconstriction, peripheral/cerebral vasodilation
- renal (high elimination of H+, bicarbonate retention)
-increased bone resorption
- hyperpotassemia