Transition block: physiology

Question 1

What FEV1/FVC ratio is seen in COPD?

Answer 1

less than 70%

Question 2

What are the two parts of COPD?

Answer 2

bronchitis and emphysema

Question 3

Describe bronchitis

Answer 3

engorged mucosa occlude the lumen causing obstruction to the airway

Question 4

Describe emphysema

Answer 4

destroys collagen and therefore, the alveolar walls

reduces the area for gas exchange

Question 5

Which type of inflammation is seen in COPD?

Answer 5

neutrophilic

Question 6

What is the FVC in asthma?

Answer 6

normal

Question 7

What is pulmonary compliance?

Answer 7

the effort the lungs go to stretch ie. effort of inhalation

Question 8

When is pulmonary compliance

a) increased?
b) decreased?

Answer 8

a) emphysema due to loss of elasticity

b) pulmonary fibrosis, oedema, lung collapse, pneumonia, absence of surfactant

Question 9

When is peak flow useful?

Answer 9

obstructive airways disease

Question 10

What is dynamic airway compression?

Answer 10

rising pressure in the lungs when you are breathing in will compress the alveoli and airways to push the air out

Question 11

When is there dynamic airway compression in obstructive lung disease?

Answer 11

during active expiration

Question 12

What happens to intrapleural and intra-alveolar pressure during

a) inspiration?
b) expiration?

Answer 12

a) falls

b) rises

Question 13

What is the primary determinant of airway resistance?

Answer 13

the radius of the conducting airway

Question 14

What is the total lung capacity equal to?

Answer 14

vital capacity (max volume out after max inhale) + residual volume (min vol left over)

Question 15

Average capacity of the lungs

Answer 15

5.7L

Question 16

When does the residual volume increase?

Answer 16

When the elastic recoil of the lungs is lost eg. emphysema

Question 17

Which is higher between intra-alveolar and intra-pleural pressure?

Answer 17

intra-alveolar

Question 18

When does pulmonary vasoconstriction occur?

Answer 18

when there is a low PO2

Question 19

What is the functional residual capacity in a young, adult man?

Answer 19

approximately about 2.2 litres

Question 20

Where would the trachea be in a tension pneumothorax?

Answer 20

deviated away

Question 21

A previously fit 22 old man has been unwell for 2 days. He presents with cough productive of greenish septum, fever, and shortness of breath. His PO2 is 8.2 kPa. What is his saturation likely to be?

Answer 21

90%

Question 22

Mechanism of breathlessness in anxiety

Answer 22

hyperventilation stimulates increased central and autonomic arousal

Question 23

Breathlessness worse at night would indicate

Answer 23

PND –> heart failure

Question 24

Mechanism of breathlessness in heart failure

Answer 24

Reduced pulmonary compliance and impaired gas diffusion

Question 25

In a patient with pulmonary fibrosis, the FEV1/FVC% is likely to be

Answer 25

80%

Question 26

Saturation in severe anaemia will be

Answer 26

still high because the haemoglobin that is there is saturated there just isn’t a lot of it

Question 27

Is a patient with a tension pneumothorax likely to be hypertensive or hypotensive?

Answer 27

hypotensive as they will go into shock

Question 28

if someone who has pulmonary fibrosis does exercise will they become hypercapnic?

Answer 28

no

CO2 diffuses more readily than oxygen so it is less affected by impaired diffusion

Question 29

What would you expect to see in someone with diabetic ketacidosis?

Answer 29

pH low
CO2 (low if compensating, high if uncompensated)
HCO3 low

Question 30

What will you expect to see in acute vs chronic respiratory acidosis

Answer 30

pH low
CO2 high
HCO3 (low in acute, high in chronic)

Question 31

Which drugs improve prognosis in heart failure?

Answer 31

ACEi
B-blockers
ARB
spironolactone

Question 32

Which drug is contraindicated in heart failure?

Answer 32

CCB slows heart rate and reduces CO

Question 33

Which drugs improve symptoms in heart failure?

Answer 33

loop diuretics
digoxin (takes a while to act)
vasodilators (nitrates)

Question 34

Which ABG pattern is seen in drug overdose?

Answer 34

respiratory acidosis

Question 35

How does a tension pneumothorax present?

Answer 35

P-THORAX
pleuritic pain
tracheal deviation
hyperresonance
onset sudden
reduced breath sounds
absent fremitus
x-ray shows collapse

Question 36

Causes of respiratory alkalosis

Answer 36

Anxiety – often referred to as a panic attack
Pain – causing an increased respiratory rate
Hypoxia – resulting in increased alveolar ventilation in an attempt to compensate
Pulmonary embolism
Pneumothorax
Iatrogenic (excessive mechanical ventilation)

Question 37

Causes of metabolic alkalosis

Answer 37

Gastrointestinal loss of H+ ions – vomiting/diarrhoea

Renal loss of H+ ions – loop and thiazide diuretics / heart failure / nephrotic syndrome / cirrhosis / Conn’s syndrome