Mechanics Of Breathing-2

Question 0

What parameters are used to calculate vital capacity ?

Answer 0

Tidal volume
Inspiratory reserve volume
Expiratory reserve volume

Question 1

What technique is used for testing lung volume ?

Answer 1

Spirometry

- measures tidal volume, inspiratory reserve volume, excitatory reserve volume

Question 2

For a 70kg man what are the values of the different lung volumes and capacities ?

Answer 2

Tidal volume= 500 ml 
Inspiratory reserve volume= 3000ml
Exploratory reserve volume= 1000ml 
Residual volume = 1200ml 
Inspirit pry capacity = Tv + irv = 3500ml 
Vital capacity= tv+irv+ erv= 4500ml

Question 3

What is functional residual capacity ?

Answer 3

Volume of air in the lungs at the end of tidal expiration

Erv + residual volume= 2200ml

Question 4

How do you calculate total lung capacity ?

Answer 4

Tidal volume + expiratory reserve volume + inspiratory reserve volume + residual volume= 5700ml

Question 5

Define tidal volume

Answer 5

Volume of air that moves into and out of the lungs during a single unforced breath

Question 6

What is inspiratory reserve volume ?

Answer 6

Max volume of air that can be inspired at the end of a normal inspiration

Question 7

What is expiratory reserve volume ?

Answer 7

Max volume of air that can be expired at the end of a normal expiration

Question 8

What is residual volume. ?

Answer 8

Volume of air remaining in the lungs at the end of max expiration

Question 9

What is the helium dilution test ?

Answer 9

Helium is almost insoluble in blood
Used to measure residual volume
Subject breathes in a gas mixture containing known conc of helium
In inspiration this mixes with air in the lungs and dilutes the helium
Subject exhales and the concentration of helium is compared to original

Question 10

What is minute ventilation ?

Answer 10

Total amount of air flowing into or out of respiratory system per minute
Tidal volume * respiration rate

Question 11

What is the typical amount of air which reaches alveoli ?

Answer 11

350ml - 70%

Question 12

What is alveolar ventilation ?

Answer 12

It is a measure of the volume of fresh air reaching the alveoli each minute - includes the correction for the dead space volume

Question 13

What is FVC ?

Answer 13

Forced vital capacity - volume of air expired after a max inspiration

Question 14

What is FEV1 ?

Answer 14

Forced expiratory volume in 1 second- volume of air expired in 1 second after max inspiration

Question 15

What is the normal FEV1:FVC ratio ?

Answer 15

80%

Lower than this indicates airway resistance

Question 16

What is another method for assessing airway resistance ?

Answer 16

Peak expiratory flow

Question 17

What is restrictive pulmonary disease ?

Answer 17

Causes decrease lung volume, increased work of breathing and inadequate ventilation
Common cause is decreased compliance - others include weak muscles of damaged nerves
Causes shortness of breath and often a cough

Question 18

What are examples of restrictive pulmonary disease ?

Answer 18

Asbestosis
Sarcoidosis
Pulmonary fibrosis

Question 19

What is asbestosis ?

Answer 19

Inhalation of microscopic fibres of asbestosis
Reach bronchioles and alveoli they trigger lung immune response and cause inflammatory response
Macrophages phagocytise fibres and stimulate fibroblasts to deposit connective tissues
Macrophages die off relaxing cytokines which attracts more macrophages
Fibrosis occurs causing thickening of alveolar Wales and reduced lung elasticity and reduces gas diffusion

Question 20

What is obstructive pulmonary disease ?

Answer 20

Obstruction of airways often caused by inflamed and/or easily collapsible airways
Obstructed airflow
Problems exhaling
Frequent hospitalisation
Symptoms : cough, shortness of breath, wheezing, fatigue

Question 21

What is asthma, ?

Answer 21

Common inflammatory disease of airways
Genetic and environental factors
Triggered by allergens, irritants, drugs, infections and exercise

Question 22

What are the drugs used to treat asthma ?

Answer 22

Beta agonists - salbutamol - cause bronchodilation

Corticosteroids- reduce inflammatory response