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physiology :( y2s1 > mechanics of breathing : compliance > Flashcards

mechanics of breathing : compliance Flashcards

1
Q

what is minute ventilation? and what is the equation?

A

amount of air going in and out the lung in a minute

Minute ventilation = Tidal volume x Frequency

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2
Q

what is alveolar ventilation and what is the equation for it?

A

amount of air REACHING the alveoli per minute

Alveolar ventilation = (TIDAL VOLUME - DEAD SPACE VOLUME ) x Frequency

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3
Q

what is the other equation for alveolar ventilation?

A

Alveolar ventilation = Rate of carbon dioxide production x K
—————————————————————–
Partial pressure of CO2

OR

Partial pressure of CO2 = Rate of carbon dioxide production x K
————————————————————-
Alveolar ventilation

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4
Q

according to the equation above what are the relations?

A

Alveolar ventilation is directly proportional relation to Rate of carbon dioxide production SO CARBON DIOXIDE INCREASES ALVEOLAR VENTINLATION

Alveolar ventilation is directly INVERSLY RELATED TO partial pressure of CO2 SOOO DECREASE IN VENTILATION WILL LEAD TO INCREASED PARTIAL PRESSURE OF CO2

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5
Q

how to calculate partial pressure of gas?

A

barometric measures x concentration of the gas

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6
Q

when is K constant?

A

body temperature (310K ) or 37 C

ambient pressure (760 mmhg)

gas saturated with water vapor

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7
Q

what happens to partial pressure of CO2 when you INCREASE alveolar ventilation?

A

partial pressure of CO2 will DECREASE because INCREASED VENTILATION = HYPERVENTILATION = NO CO2 ACCUMULATION

they are inversely related

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8
Q

what happens to partial pressure of CO2 when you DECREASE alveolar ventilation?

A

partial pressure of CO2 will INCREASE because DECREASED VENTILATION = HYPOventilation = CO2 ACCUMULATION IN THE LUNG

INVERSELY RELATED

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9
Q

whats the equation of partial pressure of CO2?

A

Partial pressure of CO2 = Rate of CO2 production x K
———————————————
Alveolar ventilation

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10
Q

what happens to alveolar ventilation when production of CO2 is INCREASED? ?

A

Alveolar ventilation is directly proportional to the RATE OF CO2 production —–> SO IT WILL INCREASE

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11
Q

what happens to alveolar ventilation when production of CO2 is DECREASED ?

A

alveolar ventilation is directly proportional to the rate of CO2 production SO IT WILL DECREASE

PRODUCTION OF CO2 ACTS AS AN STIMULATANT FOR VENTILATION IF YOU INCREASE IT WILL INCREASE

hyperbolic graphs moves to the right

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12
Q

why is alveolar ventilation equation is important in monitoring ventilation efficacy?

A

equation helps to determine if alveolar ventilation is sufficient to ELIMINATE CO2 produced by the body

Low Alveolar ventilation = Hypercapnia = CO2 accumulation

High alveolar ventilation = Hypocapnia = No CO2 accumulation

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13
Q

why is alveolar ventilation equation is important in assessing respiratory disorders ?

A

condition like COPD, asthma, respiratory failure can be impair alveolar ventilation , by monitoring Partial pressure of CO2 it can assess the degree of ventilation impairment ( INCREASED CO2 PARTIAL PRESSURE MEANS HIGH DEGREE OF BLOCKAGE AND DECREASED VENTILATION ) and make decision about interventions like mechanical ventilation

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14
Q

why is alveolar ventilation equations is important in GUIDING mechanical ventilation?

A

patients on ventilators, the alveolar ventilation equation helps adjust ventilators settings to ensure appropriate removal of CO2 and prevent respiratory acidosis ( INCREASING VENTILATION WILL REDUCE CO2 )

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15
Q

how to calculate alveolar partial pressure of oxygen?

A

using alveolar gas equation

Alveolar partial pressure of oxygen = Partial pressure of inspired oxygen - (Partial pressure of carbon dioxide in the alveoli /
Respiratory exchange ratio)

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16
Q

whats the partial pressure of o2?

A

160 —> Air
150 —-> Trachea
100 —-> alveolar
100 —–> arteries
40 —> mixed veins

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17
Q

whats the partial pressure of CO2?

A

0—> air
0 —–> trachea
40—-> alveolar
40 —-> arteries
46 ——> mixed veins

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18
Q

example of calculating alveolar partial pressure of oxygen

A

in resting individuals breathing air at the sea level where :

Inspired oxygen partial pressure = 150
alveolar CO2 partial pressure = 40
Respiratory exchange ratio aka respiratory quotient = 0.8

150- (40)
—- = 150-50= 100
0.8

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19
Q

another example of calculating alveolar partial pressure of oxygen

A

man breathing room air at sea level has partial pressure of co2 of 48 , what his alveolar tension?

Inspired oxygen is always assumed to be 150
rate of exchange is 0.8

so 150- ( 48 )
—- = 150-60 = 90
0.8

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20
Q

what is the importance of alveolar gas equation for oxygen in assessing oxygenation?

A

alveolar gas equation is used to estimate the alveolar oxygen pressure which determines the efficacy of oxygen exchange in the lung

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21
Q

what is the importance of alveolar gas equation for oxygen in diagnosing hypoxemia?

A

comparing the calculated partial pressure of co2 with the measured oxygen partial pressure of pa co2

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22
Q

what is the importance of alveolar gas equation for oxygen therapy?

A

the equation is useful when adjusting oxygen therapy such as determining the required fraction of inspired oxygen FIO2 to achieve the desired oxygen level in the blood especially in patients with respiratory distress or failure

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23
Q

what are the 3 factors affecting pulmonary ventilation?

A

1- lung compliance

2- alveolar surface tension

3- airway resistance

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24
Q

what is compliance?

A

how easily the structure can be stretched in this case it is the lungs

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25
what is the equation for compliance?
compliance = Change in volume ------------------------------------ change in pressure Increased volume = increased compliance Increased CHANGE in pressure = DECREASED COMPLIANCE measured by L/cm H2O unit
26
what happens when the lungs are filled?
the more they are filled the harder it is to fill them more, as it is getting filled it is harder to fill ---> Decreased compliance
27
what are the 2 factors that DECREASE compliance?
elastic recoil Surface tension of the alveoli both will make it harder to for the lung to stretch and decrease compliance
28
what DOESNT compliance depend on?
compliance it is a static phenomenon doesnt depend on air or tissue movement
29
what is elasticity of the lung?
the lung ability to recoil or wanting to recoil IT IS opposite to compliance
30
what is the equation for elasticity?
elasticity = Change in pressure ------------------------------------- change in volume Increased change in pressure = increase elasticity Increased volume = DECREASED elasticity
31
what is the relation between compliance and elasticity ?
Elasticity is recoil and compliance is stretch so they are opposite INVERSELY RELATED The greater the number of elastic fibers ---> LESS COMPLIANCE ( THICKER BALLOON) The lesser the number of elastic fibers ----> MORE COMPLIANCE ( THINNER BALLON)
32
what is pressure volume curve of the lung?
experiment of lung being isolated and placed in a jar where pressure exerted on the lung can be altered and it is connected to a spirometer to measure volume
33
what happens to the pressure and the line in INSPIRATION?
when inflate the lungs in inspiration the VOLUME INCREASE and IN ORDER FOR THIS INFLATION TO HAPPEN THE PRESSURE MUST BE MORE NEGATIVEEE ---> LINE MOVES UPWARD AND TO THE RIGHT
34
what happens to the pressure and the line in expiration?
when deflating the lungs : EXPIRATION the volume IS DECREASING and IN ORDER FOR THIS TO HAPPEN THE PRESSURE MUST BE POSITIVE ( boylaw law, higher volume = less pressure and vice versa ) = LINE MOVES DOWNWARD AND LEFT
35
what hysteresis?
phenomenom where both lines are expected to overlap but they didnt
36
what was the cause of hysteresis?
the lines didnt overlap because of SURFACE tension they figured that if they remove the surface tension by replacing it with a saline fluid
37
how does surface tension affect the lungs?
surface tension makes it harder to open the lungs ( decreases compliance ) Make it easier to close up the lung and recoil ( increase elasticity ) Two third of the work is required to overcome surface tension while one third is required to overcome elastic recoil
38
why does the the curve for chest wall and the lung only have similar slope?
because they are considered separate balloons each with its own compliance
39
how do we obtain the chest wall only curve?
subtract the lung only from chest wall and lung curve
40
whats special about the compliance of chest wall and lung curve?
it is less compliance because when you put one of the balloons inside the other the compliance would be less
41
what happens to the curve in emphysema?
in emphysema lung expands easily = HIGH COMPLIANCE but not recoil easily due to the lose of elasticity Compliance curve becomes Straighter HIGHER equilibrium point so they will breath GREATER VOLUME ( lung expands easily and accommodate higher volume ) --> HYPERVENTILATION the two opposite and equal forces between the collapsing and expanding force will become unbalanced --> shifts to the LEFT COLLAPSING FORCE IS LESS BECAUSE NO ELASTIC FIBERS, body will adjust this by retaining more air to maintain the equal and opposite curve at the FRC
42
what happens to the curve in fibrosis?
patient with fibrosis lung does NOT expand easily = LOW COMPLAINCE Compliance curve shifts FLATTER fibrosis has LOWER equilibrium so they will breath LOWER VOLUME = HYPOVENTILATING Collapsing force is HIGHER because low compliance = shifts to the right
43
what diseases increase compliance?
Emphysema
44
what diseases DECREASE compliance?
pulmonary fibrosis pul vascular congestion Pneumonia pleural effusion decreased Surfactant ( this will increase surface tension so decrease compliance ) spine deformity obesity
45
how is surface tension formed ?
interaction between fluid molecules in the air the fluid molecules are attached to each other and tend to come close in proximity as they are like each other.
46
what will the surface tension try to do?
collapse the alveoli
47
what are the forces acting to keep the alveoli OPEN?
Transmural pressure gradient Pulmonary surfactant which decreases alveolar surface tension Alveolar interdependence
48
what are the forces that are acting to COLLAPSE the alveoli ?
Elasticity of stretched lung Surface tension
49
what laplace equation for surface tension ?
P = 2 T ------------------------ r P = pressure inside alveoli T= surface tension r = Radius
50
based on the equation what affects the pressure in alveoli in case of absence of surfactant
Surface tension --> from the interaction between fluid molecules in the air radius
51
what happens to pressure in small alveolis?
small radius so higher pressure ( because pressure is inversely related to radius )
52
what happens to pressure in large alveolis?
large radius will have low pressure
53
what would the difference in pressure do?
air will move from high pressure to low pressure it will go from small alveoli to large alveoli ---> small alveoli WILL COLLAPSE
54
what does the surfactant do the pressure?
surfactant will REDUCE surface tension --> WILL REDUCE THE PRESSURE IN SMALL ALVEOLI to make comparable to large alveoli = balance things out so air will be similar --> ALVEOLAR STABILITY
55
which cells produce surfactant?
type 2 pneumocytes
56
what are surfactants?
phospholipids substances produced BY FATTY acids in TYPE 2 pneumocytes
57
why does pulmonary surfactant reduces surface tension?
1- Promote stability of the lung -> prevent small alveoli from emptying into large alveoli and collapsing 2- Reduce inflation pressure and work of breathing 3- Helps keeps the lung dry
58
what does less surfactant result to?
results in higher surface tension and decrease compliance MORE fluid filtration and thus edema
59
what are the causes of reduced surfactant activity?
1- Neonatal respiratory distress syndrome ( hyaline membrane disease ) --> Surfactant normally appear at about 34 weeks of gestation LESS SURFACTANT = INCREASES TENSION = DECREASED COMPLIANCE LUNG CANT EXPAND 2- Adult respiratory distress syndrome 3- post cardio pulmonary bypass 4- pulmonary embolus 5- oxygen toxicity and other toxic agents
60
what is alveolar interdependence?
when you have interconnected alveoli ( multiple alveoli connected ) if the central alveoli collapse = The surrounding alveoli will pull it to open it UP = alveolar stability
61
what are 2 types of airflow in the lung?
Turbulent flow laminar flow
62
where is the turbulent flow present?
larg airways like trachea and bronchi
63
where is the laminar flow present?
small peripheral airways
64
whats the equation for airway resistance?
R = Pressure difference ( Pmouth - P alveoli ) ------------------------------------------------------------------- Air flow it is derived from flow = Pressure difference ----------------------------------- resistance
65
how does resistance affect the flow?
movement of air into and out the lung there is frictional resistance that needs to be overcome, higher resistance = higher work needed to overcome this resistance Work of breathing increases when resistance is increased
66
where is the airway resistance primarily found?
upper airways because the diameter in the lower bronchioles combined is higher than upper ways ( higher diameter = less resistance )
67
describe the relation between air resistance and radius?
airway resistance is inversely proportional to the fourth power of the radius according poiseuille law
68
how is the resistance arranged in small airway?
they are arranged in parallel the combined resistances are lower than each individual
69
what are the factors that frequently affect the airway diameter?
Bronchoconstriction mucus buildup inflammation and edema
70
what is poiseuille law?
R = 8 x viscosity x L --------------------------------------------------- pi x r4 R = resistance L= length r= radius
71
according to poiseuille law whats the major determinants of airway resistance?
radius because it is to the power 4 if radius doubles the resistance decrease by 16 if radius increased by half resistance increase by 16 medications work on changing the radius
72
where is the smallest radius found?
bronchi = smallest radius and highest resistance
73
where is the highest radius found?
terminal bronchioles because they are many like capillaries = lowest resistance
74
what does decreased partial pressure of co2 does as a reflex?
increases resistance by bronchoconstriction --> decreases the flow = keeps more co2 and increase the partial pressure of co2
75
what are things that cause bronchoconstriction ?
parasympathetic histamine decreases CO2 pressure excessive mucus, tumor, edema, collapse
76
what are things that cause bronchodilation?
sympathetic epinephrine increased co2 pressure
77
what is the effect of increased lung volume in resistance?
lungs inflated = alveoli interdependance = they pull each others open = increase radius = DECREASE RESISTANCE
78
what is the effect of decreased lung volume in resistance ?
decreased lung volume ( lungs deflate and collapse = reduced radius = increased resistance )
79
what does increased lung volume change?
compliance is decreased elastic work is increased resistance is decreased and vice versa
80
how do you help someone who has difficulty breathing breath ?
raise their arms = increase lung volume = decreased resistance
81
what happens to intrapleural pressure during forced expiration?
it becomes positive so the pressure inside alveoli is more than atmosphere = air leaves
82
what does forced expiration does to the airway resistance?
it will compress the airway = reduces radius = increase airway resistance , this will build up the pressure to get rid of the foreign material
83
what are examples of forced expiration?
blowing a candle and coughs
84
why doesnt lung collapse although the intrapleural pressure is positive?
because the transmural pressure is positive as long as it is positive it will remain open
85
what happens to the large alveoli in emphysema?
in emphysema there is no elastic recoil so the transmural pressure gradient across the lung remains positive expanding pressure +5 and the alveoli remain open but the large airways collapse because TRANSMURAL PRESSURE gradient across them REVERSE becoming NEGATIVE = when transmural pressure becomes negative = collapse
86
why do patients with emphysema purse their lips?
pursed lips creates high resistance at mouth and raise airway pressure this prevents the reversal of transumular pressure gradient and prevent lung collapse
87
what is transmural pressure?
pressure inside alveoli - pressure outside alveoli when negative this means outside is higher than inside = collapse when positive this means inside is higher = no collapse
88
which is more affected resistance problems exhale or inhale?
exhale because in inhalation the negative pressure pull the airway open increasing the radius and decreasing the resistance in exhalation intrapleural pressure becomes positive and compression happens decreasing radius and increasing resistance
89
when is intrapleural pressure negative n positive?
intrapleural pressure is always negative this keeps the lung and the airway OPEN only time it is not negative is during FORCED EXPIRATION ( cough )
90
what is transairway pressure?
transairway pressure = pressure in airway - pleural pressure
91
when is transairway pressure positive n negative?
transairway is always positive ( pleural pressure is less than airway) it is only negative in FORCED EXPIRATION
92
what is equal pressure point? (EPP)
point where the airway pressure is equal to pleural pressure SO transairway pressure is 0 because transairway = Pairway - Ppleura
93
what does the equal pressure point divides the airway into?
1- Upstream segment --> from the ALVEOLI to the Equal pressure point 2- Downstream segment ---> from the MOUTH to the Equal pressure point --> Negative transway pressure -collapsed segment
94
what happens when the intrapleural pressure is higher than airway?
since transairway is Pairway - Pinterpleura (higher) then it the transairway will BECOME NEGATIVE this will lead to a risk of COLLAPSE USUALLY IT IS IN THE DOWNSTREAM
95
where is the Equal pressure point found in healthy lungs?
it is found in large airways ( trachea and bronchi ) , which is in the UPPER part of the airway and if it leads to collapse then THE CARTILAGE will prevent the collapse and keep the airway open ( minimal airway collapse )
96
where is equal pressure point is found in emphysema patients ?
The equal pressure point is found IN THE LOWER parts of the lung because theres destruction of elastic fibers and recoil --> the COLLAPSE happens in the LOWER AIRWAYS which is not supported by cartilage = COLLAPSE emphysema patients have hard time breathing out
97
what is positive end expiratory pressure? PEEP
supportive measurement to prevent the tendency to develop regional ATELECTASIS ( collapse ) prevent alveolar pressure to return to zero at the end of the expiration --> lung will be kept at a larger volume IT IS GIVEN IN EMPHYSEMA TO RAISE THE INTRAALVEOLAR PRESSURE AND PREVENT COLLAPSE
98
what is flow volume curve?
graphical representation of airflow in the Y AXIS and Volume in X axis during complete respiratory cycle
99
how is flow volume curve measured?
pulmonary function test --> spirometry
100
what is the benefit of flow volume curve?
provide valuable insights into lung function --> helping the diagnose and manage various respiratory condition such as obstructive pulmonary diseases and restrictive lung disease
101
where does the flow volume curve start at?
residual volume
102
what do you call the line between the beginning of forced inspiration and end of forced inspiration?
FRC or vital capacity
103
how do you calculate total lung capacity from the graph?
RV + FRC or FVC
104
which part of forced expiration is effort dependent?
the first one ( relies on muscles ) airway resistance is very low and flow is high
105
which part of forced expiration is effort INDEPENDENT?
the second part --> RELIES ON ELASTIC RECOIL AND RESISTANCE
106
what happens to the curve in obstructive lung disease?
the curve will be deviated to the left because 1- Elastic fibers are destroyed so the second part which effort independent will be disturbed 2- residual capacity will be increased because air will struggle to leave 3- problem in expiration because no elastic fibers and air cant leave properly
107
what happens to the curve in restrictive lung diseases?
curve will be shifted to the right because 1- The lung wont expand and air wont get it in as much 2- Expiration will be the same, it is js taht the lung cant get a lot of volume no more
108
which capacities are gonna be increased in obstructive lung disease?
IN obstructive : Total lung capacity ( air cant leave ) Functional residual capacity ( Air cant leave ) Residual volume ( air cant be leave ) will ALL BE INCREASED
109
which capacities are gonna be DECREASED in restrictive lung disease?
in restrictive : TOTAL LUNG CAPACITY FUNCTIONAL RESIDUAL CAPACITY RESIDUAL VOLUME all are gonna be DECREASED because : 1- lungs cant fill or expand 2- expiration is not affected so it will continue to push out the air leading to the decrease RESTRICTIVE / RIGHT / REDUCE

physiology :( y2s1 (15 decks)

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