Ventilation

Question 1

What is pulmonary ventilation? And notation?

Answer 1

Vpulm. Volume of air inhaled per minute.

Question 2

What is minute ventilation? Notation

Answer 2

The volume of air expired in one minute (VE).

Question 3

What is respiratory rate and its notation?

Answer 3

Rf. The frequency of breathing per minute.

Question 4

What is alveolar ventilation and its notation?

Answer 4

Valv. The volume of air reaching the respiratory zone per minute.

Question 5

What is respiration?

Answer 5

The process of generating ATP either with an excess of oxygen (aerobic) or a shortfall (anaerobic).

Question 6

What is hypoventilation? Result in blood?

Answer 6

Deficient ventilation of the lungs; unable to meet metabolic demand (increased PCO2 – acidosis).

Question 7

What is hyperventilation? Result in blood?

Answer 7

Excessive ventilation of the lungs atop of metabolic demand (results in reduced PCO2 - alkalosis)

Question 8

What is hyperpnoea?

Answer 8

Increased depth of breathing (to meet metabolic demand).

Question 9

What is hypopnoea?

Answer 9

Decreased depth of breathing (inadequate to meet metabolic demand).

Question 10

What is apnoea?

Answer 10

Cessation of breathing (no air movement).

Question 11

What is dyspnoea?

Answer 11

Difficulty in breathing.

Question 12

What is bradypnoea?

Answer 12

Abnormally slow breathing rate.

Question 13

What is tachypnoea?

Answer 13

Abnormally fast breathing rate.

Question 14

What is orthopnoea?

Answer 14

Positional difficulty in breathing when lying down.

Question 15

How is the nose and mouth used in breathing at rest and at deep breathing?

Answer 15

AT REST: breath in and out through the nose. DEEP BREATHING: uses mouth and nose to reach total lung capacity before decreasing to residual volume.

Question 16

What are the names of the different VOLUMES in the lung and breathing pattern? (x4)

Answer 16

Tidal volume: volume per breath (increases during exercise). Inspiratory reserve volume: extra space in the lungs after normal inspiration available for inspiration. Expiratory reserve volume: extra space after normal expiration to force expiration. Residual volume: anatomical limit to air capacity in the lungs, that prevents complete exhalation.

Question 17

What is the difference between a volume and capacity?

Answer 17

VOLUMES: are discrete and don’t overlap. CAPACITIES: sums of volumes.

Question 18

What are the names of different CAPACITIES in the lung and breathing pattern? (x3)

Answer 18

Functional residual capacity: amount of air left in the lungs after normal expiration. Inspiratory capacity: amount of air that can be forcibly inhaled from normal breathing. Vital capacity: how much air can be adjusted – useful air.

Question 19

What factors affect lung volumes and capacities? (x5)

Answer 19

What factors affect lung volumes and capacities? (x5) Body size (height and shape – but obesity does not increase size of lungs). Sex (males are larger). Disease (lung muscle, tissue disorders, neurological). Age (decreases with age). Fitness (innate fitness >> training).

Question 20

What is a restrictive airways disease?

Answer 20

Inflation/deflation of the chest/lungs are restricted, and lungs operate at lower volumes because people cannot fully fill their lungs with air (lung fibrosis, obesity…). Normal rate of exhalation but reduced FVC (forced vital capacity).

Question 21

What is obstructive airways disease?

Answer 21

Flow into/out of lungs obstructed so lungs operate at higher volumes because of damage to the lungs or narrowing of airways (asthma/COPD). Reduced rate of exhalation and markedly reduced FVC.

Question 22

How do lung volumes differ in normal, obstructive and restrictive lung diseases?

Answer 22

NORMAL.

OBSTRUCTIVE: IRV, TV and ERV (inspiratory reserve, tidal, expiratory reserve) DECREASE because air is TRAPPED inside the lungs because of bronchoconstriction. Residual volume therefore is MUCH higher.

RESTRICTIVE: everything is decreases, especially residual volume.

Question 23

What chronic and acute causes are there of obstructive and pulmonary and extrapulmonary causes of restrictive pulmonary diseases?

Answer 23

OBSTRUCTIVE: Chronic (COPD (emphysema, bronchitis)), acute (asthma). RESTRICTIVE: Pulmonary (Lung fibrosis and interstitial lung disease), extrapulmonary (obesity and neuromuscular disease).

Question 24

What are the three types of dead space, in relation to ventilation?

Answer 24

Anatomical, alveolar, physiological.

Question 25

What is anatomical dead space?

Answer 25

The capacity of the airways incapable of undertaking gas exchange – the conducting zone (including nose, pharynx and larynx).

Question 26

What is alveolar dead space?

Answer 26

Capacity of the airways that should be able to undertake gas exchange but cannot (e.g. hypo-perfused alveoli). Usually the non-perfused parenchyma, which should be 0ml in adults.

Question 27

What is physiological dead space?

Answer 27

Equivalent to the sum of alveolar and anatomical dead space.

Question 28

What value should physiological dead space be?

Answer 28

150ml in adults.

Question 29

What is the conducting zone of the lungs? What dead space does it refer to?

Answer 29

Upper branches where no gas exchange occurs. Has 16 generation (meaning 15 bifurcations). Equivalent to ANATOMICAL DEAD SPACE.

Question 30

What is non-perfused parenchyma? What dead space does it refer to?

Answer 30

Alveoli without blood supply, so no gas exchange. Should be 0mL in adults. Equivalent to ALVEOLAR DEAD SPACE.

Question 31

What is the respiratory zone of the lungs? What dead space does it refer to?

Answer 31

It is the lower branches where gas exchange occurs. Has 7 generation (meaning 6 bifurcations). It is not equivalent to any dead space. It is equivalent to alveolar ventilation.

Question 32

What procedures can reversibly decrease and increase someone’s dead space? (x2, x1)

Answer 32

Dead space refers the blue section of the photo (the green bit is the respiratory zone)!!! DECREASE DEAD SPACE: tracheotomy (tube through neck for breathing), cricothyrocotomy (like tracheotomy, but as emergency). INCREASED DEAD SPACE: anaesthetic circuits (used to regulate concentrate concentrations of inhaled gases and includes a reservoir bag).

Question 33

What is Boyle’s law?

Answer 33

Pressure of the gas is inversely proportional to the volume of gas.

Question 34

What are the regional differences in ventilation and perfusion in the apex and base of the lungs? What is this concept called?

Answer 34

LUNG APEX: alveoli are stretched because of gravity, so need greater pressure to inflate (less compliant and perform less ventilation). Simultaneously, blood is pulled downwards so there’s a lower intravascular (inside blood vessel) pressure in the apex – causing reduced perfusion. LUNG BASE: alveoli are squashed (they are not stretched by gravity – they are squashed because of gravity), so have the ability to inflate much more – performing more ventilation. Simultaneously, blood is pulled downwards to produce a higher intravascular pressure, increasing perfusion. This is known as ventilation-perfusion matching: perfusion and ventilation BOTH increase going towards the lung base (but perfusion does so at a much greater rate).

Question 35

What is wasted ventilation and wasted perfusion?

Answer 35

WASTED VENTILATION: occurs at the apex because perfusion cannot meet the demands of the ventilation supplied. WASTED PERFUSION: occurs at the base because ventilation cannot meet the demands of the blood perfused.

Question 36

What is ventilation-perfusion ratio?

Answer 36

V/Q ratio would be 1 if perfusion and ventilation matched. But gravity means that there are regional changes. Calculated as alveolar ventilation/cardiac output. Averages approx. 0.84 in a healthy lung.