Physiology

Question 1

what is a normal value for the FEV1/FVC ratio?

Answer 1

> 75%

Question 2

what is the value for FEV1/FVC in asthma and what can change this?

Answer 2

<75%

reversibility response to bronchodilator

Question 3

what is the value of FEV1/FVC that is diagnostic for COPD?

Answer 3

<70% post bronchodilator

Question 4

what is considered to be mild COPD on the GOLD classification?

Answer 4

FEV1 >80% predicted

Question 5

what is considered to be moderate COPD on the GOLD classification?

Answer 5

FEV1 50-79% predicted

Question 6

what is considered to be severe COPD on the GOLD classification?

Answer 6

FEV1 30-49% predicted

Question 7

what is considered to be very severe COPD on the GOLD classification?

Answer 7

FEV1 <30% predicted

Question 8

what effect can obesity have on the functional residual capacity?

Answer 8

decreased

Question 9

what effect does COPD have on functional residual capacity?

Answer 9

increased

Question 10

what lung volumes and capacities cannot be measured by spirometry?

Answer 10

residual volume
functional residual capacity
total lung capacity

Question 11

what is the tidal volume (TV)?

Answer 11

volume of air entering or leaving lungs during a single breath

Question 12

what is the inspiratory reserve volume (IRV)?

Answer 12

extra volume of air that can be maximally inspired over and above the typical resting tidal volume

Question 13

what is the expiratory reserve volume (ERV)?

Answer 13

extra volume of air that can be actively expired by maximal contraction beyond the normal volume of air after a resting tidal volume

Question 14

what is the residual volume (RV)?

Answer 14

the minimum volume of air remaining in the lungs even after a maximal expiration

Question 15

what is the inspiratory capacity (IC)?

Answer 15

maximum volume of air that can be inspired at the end of a normal quiet expiration

Question 16

how is inspiratory capacity calculated?

Answer 16

inspiratory reserve volume + tidal volume

Question 17

what is the functional residual capacity?

Answer 17

volume of at the end of normal passive expiration

Question 18

how do you calculate the functional residual capacity?

Answer 18

expiratory reserve volume + residual volume

Question 19

what is the vital capacity?

Answer 19

the minimum volume of air that can be moved out during a single breath following a maximal inspiration

Question 20

how do you calculate vital capacity?

Answer 20

inspiratory reserve volume + tidal volume + expiratory reserve volume

Question 21

what is the total lung capacity?

Answer 21

total volume of air the lungs can hold

Question 22

how do you calculate the total lung capacity?

Answer 22

TLC = VC + RV

Question 23

what effect does increasing partial pressure have on the rate of gas transfer?

Answer 23

increases rate of transfer

Question 24

what effect does increasing diffusion coefficient have on the rate of gas transfer?

Answer 24

increases rate of transfer

Question 25

what effect does increasing surface area of the alveolar membrane have on the rate of gas transfer?

Answer 25

increases rate of transfer

Question 26

what effect does increasing thickness of the alveolar membrane have on the rate of gas transfer?

Answer 26

decreases rate of transfer

Question 27

what is pulmonary compliance?

Answer 27

a measure of the effort that has to go into stretching the lungs the change in lung volume per unit change in the transmural pressure gradient across the lung wall

Question 28

what does reduced pulmonary compliance mean?

Answer 28

more work needed to inflate the lungs

Question 29

name some things that can cause decreased pulmonary compliance

Answer 29

``` pulmonary fibrosis oedema lung collapse pneumonia lack of surfactant ```

Question 30

what symptom does a lack of pulmonary compliance cause?

Answer 30

SOB - especially on exertion

Question 31

what can be seen on spirometry in a patient with decreased pulmonary compliance?

Answer 31

restrictive pattern

Question 32

what effect can giving excessive oxygen have on COPD patients?

Answer 32

can lead to hypercapnic respiratory failure due to CO2 retention

Question 33

what is the target SaO2 in patients with COPD?

Answer 33

88-92%

Question 34

name a condition that can cause abnormal increase of pulmonary compliance

Answer 34

emphysema (COPD)

Question 35

what effect does increasing age have on compliance?

Answer 35

compliance increases as you become older

Question 36

what is CaO2?

Answer 36

the oxygen content of arterial blood

Question 37

how is CaO2 determined and what is the equation for this?

Answer 37

by the Hb concentration and the Hb saturation CaO2 = 1.34 x [Hb] x SaO2

Question 38

what three things can impair oxygen delivery to the tissues?

Answer 38

respiratory disease heart failure anaemia