Spirometry

Question 1

Muscles of normal inspiration

Answer 1

External intercostals
Diaphragm

Question 2

Accessory muscles of inspiration (DIB)

Answer 2

Sternocleidomastoid
Scalenes
Pectoralis minor

Question 3

Expiration

Answer 3

Passive during normal expiration (recoil)

Question 4

Active expiration

Answer 4

Internal intercostals
Abdominal muscles

Question 5

Inhaled foreign body

Answer 5

Expiratory CXR with show air trapping
- Intrathoracic airways collapse on expiration

Question 6

Lung Compliance

Answer 6

Change in volume for a given change in pressure

Question 7

Compliance

Answer 7

Measure of how easy lungs are to inflate
Idea of ventilation/ perfusion
Higher = easier to ventilate
Low compliance = stiff lungs.

Question 8

Surfactant

Answer 8

Secreted by Type 2 pneumotypes (from 24 weeks)

Increases lung compliance

Question 9

Surfactant Components

Answer 9

Phosphatidylcholine main component (65%)

Surfactant proteins B & C functional
A & D have immunological functions

Question 10

Resistance

Answer 10

How hard you have to work, to get air through airway - how much pressure to drive flow

Higher resistance, the slower the ventilation
High resistance in airway obstruction (e.g. asthma)

Question 11

Myoglobin

Answer 11

Has highest affinity for oxygen

Question 12

Alveolar oxygen content

Answer 12

13.3kPa

Question 13

Serum PaO2

Answer 13

13kpa

Question 14

Cause of V:Q mismatch

Answer 14

Pneumonia
RDS
Anaesthesia

Question 15

Hypoxic Pulmonary Vasoconstriction Reflex

Answer 15

Regional differences in ventilation/ perfusion

Lung compensate by bypassing areas of poor ventilation e.g. white out RLL, will reduce blood flow to this area

Question 16

Residual volume

Answer 16

Whats left in the lung after deep breath in and out
Can’t get rid of it

Question 17

Vital Capacity

Answer 17

Full inspiration + expiration

Question 18

Tidal volume

Answer 18

Movement in normal breathing

Question 19

TLC

Answer 19

Total volume of lung, including air that can’t be moved

Question 20

Inspiratory reserve volume

Answer 20

The extra breath in on top of TV

Question 21

Expiratory volume

Answer 21

Extra expiration on top of TV (ignoring RV)

Question 22

Z score

Answer 22

(Measured value - Predicted value)/ SD of predicted value

Remember distribution either side
e.g. -1.96 z score is 2.5th centile
-1.645 = 5th centile
Normal = 0

Question 23

Restrictive causes

Answer 23

Interstitial lung disease
Scoliosis
Muscular dystrophy

Question 24

Bronchodilator responsiveness

Answer 24

FEV1 increase >12 % after bronchodilator

Question 25

Physiological changes in REM

Answer 25

Rapid eye movements Variable tidal volume and FRC Variable HR Relaxation of all skeletal muslce i.e. diaphragm is main working muscle

Question 26

Prolonged moist cough

Answer 26

Haemophilus influenzae