respiratory physio 2 Flashcards

1
Q

spirometer

A

-measures volumes of the lungs (breathing out)

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2
Q

what is tidal volume? expiratory and inspiratory reserve volume? Vital capacity? total lung capacity?

A
  • tidal vol- normal inspiration and expiration curve for a person at rest
  • expiratory and inspiratory reserve volume- when you ask the patient to breathe out and breathe in as much as they can
  • vital capacity- aka forced vital capacity is when pt is the full inspiratory reserve to expiratory reserve
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3
Q

functional residual capacity? residual capacity

A
  • where everything is balanced, no inspiration or expiration
  • at bottom of tidal volume expiration
  • functional residual capacity- the amount of air left in your lungs after expiration- CANNOT BE MEASURED BY SPIROMETRY
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4
Q

how does the inspiratory reserve volume (IRV), Vt, ERV, and RV change with restrictive lung disease? obstructive?

A

restrictive- everything decreases as there is a restriction in expansion of the lungs

obstructive- you can get better breath in more than out which causes air to get trapped in- COPD and asthma

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5
Q

forced vital capacity -
Fev 1-
what does the FEV1/FVC ratio mean? what does a higher value mean?

A
  • total volume of air that can be FORCIBLY expired following maximal inspiration
  • tell patient to breath out as hard and as fast as they can-

-Fev1- air vol that is forcibly expired in the first second

  • FEV1/FVC- the fraction of total FVC that can be expelled during the first second = REFLECTS THE RESISTANCE TO AIRFLOW
  • the higher the value of the fraction, the less resistance
  • normal: 0.75-0.8
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6
Q

describe the flow-volume curve and its values.

A
  • has a peak inspiratory flow (at bottom of curve)-reflection
  • peak lung capacity at top of curve and decreasing volume FEF 25, 50, 75% of exhaled vital capacity that ends in FVC (forced lung capacity)
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7
Q

in terms of expiration, what are large airways responsible for? small?

A

large- the beginning part of expiration to the peak

small airways- from peak and down as the airflow begins to decline

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8
Q

how does the flow-volume curve change with obstructive lung disease?

upper airway obstruction?

restrictive lung disease?

A

obstructive lung disease- expiration peak is decreased and the peak volume is also decreased (shifted to left) with steeper slope post peak

upper airway obstruction- looks like a square, don’t reach peak inspiration or expiration flows

restrictive lung disease- no obstruction just decreased airflow and thus more volume required (shift to right)- mini normal curve

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9
Q

what is the normal Fev1/FVC ratio? what does that mean?

how is that different in an obstructive lung disease pt?

restrictive lung disease pt?

A
  • normal ration is 0.8 - this means that in a normal patient, the patient should be allowed to forcibly expire about 80% of the vital capacity in the first second)
  • In obstructive lung disease, this ratio is decreased- both FVC and FEV1 are decreased but FEV1 is decreased MORE than FVC (which makes sense because there is a prob with expiration not inspiration) is causing the ratio to be under 0.7
  • in restrictive lung diseases like fibrosis you get a decrease in both FEV1 and FVC but FEV1 is decreased LESS than FVC is causing the ratio to go higher
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10
Q

what is physiological dead space and how do you calculate it?

A
  • physiological dead space(Vd) is the total volume of the lungs not used to participate in gas exchange
  • Vd = anatomic dead space + functional dead space
  • anatomic dead space is not pathologic- just the generation 1-16 bronchioles etc
  • functional dead space is always pathologic- alveoli that do not participate in gas exchange (ventilated but not perfused)
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11
Q

how do you calculate minute ventilation and what is it

A

-total rate of air movement into and out of the lungs
minute ventilation - Vt x RR
vt= tidal volume and RR is respiratory rate

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12
Q

how do you calculate alveolar ventilation RATE? what is it?

A
  • rate at which new air reaches the gas exchange areas of the lungs
    Va = RR x (Vt -Vd)
    Vt = tidal volume, Vd = dead space, RR respiration rate in breaths per min
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13
Q

what does the alveolar ventilation equation tell us? what is the equation?

A
  • it describes the INVERSE VOLUME relationship between alveolar ventilation and alveolar pCO2

Va = [Vco2 x K]/ PaCO2

Va= alveolar ventilation- amount of air reaching the alveoli per min
PaCO2- Alveolar Pco2
Vco2= rate of CO2 production
K = constant 863 mmHg

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14
Q

what happens with PAco2 if CO2 production is constant

A
  • it is determined by Va b/c

Va = [Vco2 x K]/ PaCO2

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15
Q

what happens to PaCO2 and Va if VaCO2 were increased

A

PaCO2 would increase too but Va would decrease (inversely proportional)

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16
Q

what is the function of the rib cage

A
  • to physically expand and sustain a negative pressure around the lungs as you inhale
  • ribs move up and decreases the pressure inside the cavity to allow air to enter
17
Q

diaphragm

A
  • main muscle of inspiration

- creates maximum negative pressure during inspiration by moving down (more than -100 cm H2O)

18
Q

what occurs if there is diaphragmatic paralysis or an abscess?

A

-pain with inhalation and thus more shallow breathing and more probability for pneumonia

19
Q

what do external intercostal muscles and internal intercostal muscles do?

A
  • they connect neighboring ribs
  • oriented at 90 degrees at each other and have opposing effects (internal vs external intercostals)
  • contraction in one causes collapse of the other
20
Q

what occurs if the intercostals are paralyzed

A

not much, must be a combo of diaphragmatic issues too

21
Q

what are the accessory muscles of inspiration? what does visible contraction of these muscles suggest?

A
  • scalene anterior (1st rib), medius (first), posterior (2nd)
  • sternocleidomastoid

-visible = they are ACCESSORY MUSCLES- so if you see them contract during breathing you know there is LABORED BREATHING

22
Q

what do the abdominal wall muscles do? what occurs when these muscles are congenitally absent or after abdominal surgery?

A
  • they are the most important muscles in expiration
  • contract and force diaphragm upward
  • pneumonia
23
Q

what is intraplural pressure? what is transmural pressure?

A

intraplural is the pressure across the lungs- it usually has a negative pressure that creates a suction to get air in

transmural is the pressure difference between the alveolar pressure and the intramural pressure- THE BIGGER THE TRANSMURAL PRESSURE, THE MORE THE TENDENCY TO WANT TO BRING MORE AIR IN

24
Q

what must occur to move air into and out of the lungs?

A

a pressure gradient between the atmosphere and the alveoli

25
Q

how do lung pressures work to inhale and exhale?

A
  • there needs to be a pressure gradient between the pleural cavity and the alveoli
  • when the intraplural pressure is negative, it suctions the alveoli to itself and causes negative pressure breathing
26
Q

what can occur that would mess with the negative pressure of the plural space and thus decrease the ability to ventilation?

A
  • if the pt is stabbed and there is damage to the pleura, you get positive pressure into that space and gets rid of the suction of the alveoli to it for respiration
  • if there is inside the plural cavity, there is no movement of air and pressure
  • if the interstitial space (space between alveoli) are too rigid, you don’t get a good suction thru
27
Q

what needs to occur for inspiration

A
  • the atmospheric pressure is greater than alveolar pressure because alveolar pressure is at a negative
  • since intraplural pressure is even more negative, you get inspiration
  • the greater the transmural pressure, the greater the inspiration
28
Q

As the lung volume increases, what occurs with the transpulmonary pressure? what is the transpulmonary pressure? what occurs with the plural pressure during inspiration? what occurs with the alveolar pressure during inspiration?

A
  • transpulmonary pressure is highest as the lung volume increases
  • transpulmonary pressure is the difference between the alveolar pressure and the pleural pressure
  • during inspiration, the pleural pressure is negative and increases as we move into expiration
  • during inspiration, alveolar pressure increases with the lung volume