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Flashcards in Ventilation & Compliance Deck (38)
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1
Q

Pulmonary (minute) Ventilation (L/min)

A

total air movement in/out of lungs

2
Q

Alveolar Ventilation(L/min)

A

Fresh air getting alveoli and therefore available for gas exchange

3
Q

Air from deadspace

A

150mL

4
Q

Total Pulmonary Ventilation =

A

Tidal Volume x Respiratory Rate

5
Q

Tidal Volume

A

A measure of the amount of air a person inhales during a normal breath

6
Q

Alveolar Ventilation=

A

Air to alveoli X Respiratory Rate

7
Q

Air to Alveoli =

A

Tidal - dead space (150)

8
Q

Partial pressure

A

pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whol gaseous mixture

9
Q

If the atmospheric pressure is 760mmHg (101kPa) and 21% of air we breath is O2 what is the partial pressure of the oxygen we breath

A

760 X 0.21 = 160mmHg (21kPa)

10
Q

Increased alveolar ventilation

A

Hyperventilation, PO2 rises and Pco2 falls

11
Q

Decreased alveolar ventilation

A

Hypoventilation, PO2 falls and PCO2 rises

12
Q

Law of Laplace

A

Inward directed pressure. The pressure required to keep the alveoli open
P= 2T/r

13
Q

P= 2T/r

A
T= surface tension
r= radius
14
Q

When does surfactant start to be produced

A

25 weeks gestation and completes by 36 week

15
Q

Why do babies no need a high change in pressure to inflate lungs

A

Lungs are filled with fluid and do not need to overcome surface tension (no air-water interface)

16
Q

Compliance

A

Change in volume relative to change in pressure

17
Q

High Compliance

A

Large increase in volume for a small decrease in ip pressure- easy for air to enter lungs- steep line

18
Q

Low Compliance

A

Small increase in lung volume for a large decrease in pressure- difficult to inspire- less steep

19
Q

Emphysema

A

loss of elastic tissue means expiration requires effort

20
Q

Fibrosis

A

inert fibrous tissue means effort on inspiration increases

21
Q

Compliance decreases from

A

base to apex, because of gravity apex is already stretched due to gravity and base is able to expand

22
Q

Small change in intrapleural pressure brings about a larger change in volume at

A

the base compared to the apex

23
Q

Obstructive

A

Increased compliance
Increased inspiration
Decreased expiration

24
Q

Restrictive

A

Loss of lung compliance

Decreased inspiration

25
Q

Examples of Obstructive

A

Asthma
Emphysema
Chronic Bronchitis

26
Q

Examples of Restrictive

A

Fibrosis
Infant respiratory distress syndrome (insufficient surfactant)
Oedema
Pneumothorax

27
Q

Technique used to measure abnormal lung fucntion

A

Spirometry

28
Q

Spirometry measurements can be

A

Static: volume exhaled
Dynamic: time taken to exhale is being measured as well

29
Q

What volumes can be measured by spirometry

A

everything except residual volume

30
Q

Functional residual volume

A

Expiatory reserve volume + residual volume

31
Q

Vital capacity

A

Expiatory reserve + Inspiratory Capacity + Inspiratory reserve

32
Q

FEV1/FVC ratio is restrictive

A

High

33
Q

FEV1/FVC in obstructive

A

low (both FEV1 and FVC fall so air comes out more slowly)

34
Q

FEF (25-75)

A

Average expired flow over the middle of an FVC

35
Q

Expiratory Reserve Volume

A

the additional amount of air that can be expired from the lungs by determined effort after normal expiration

36
Q

Functional Residual Capacity

A

the volume of air present in the lungs at the end of passive expiration

37
Q

Residual Volume

A

the amount of air that remains in a person’s lungs after fully exhaling

38
Q

Vital Capacity

A

the maximum amount of air a person can expel from the lungs after a maximum inhalation