6) Principles Of PFT & ABG Testing Flashcards Preview

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Flashcards in 6) Principles Of PFT & ABG Testing Deck (55):
1

Hypercarbia

Respiratory failure from too much CO2

2

Hypoxemia

Not enough O2 in the blood

3

Hypoxia

Not enough O2 at the tissue level

4

What can lead to hypoxia?

Hypoxemia

5

Chemoreceptors

Sense O2 content of blood

6

Partial Pressure

O2 dissolved in blood plasma

7

Respiratory Acidosis

Can't get blow off CO2 so blood becomes acidic

8

Respiratory Alkalosis

Blow off too much CO2 so blood becomes basic

9

What is the physiologic mechanism of breathing?

1) Chemoreceptors in the carotid & aorta respond to changes in blood chem

2) Signals are sent to the medulla as PaO2 & PaCO2 change

3) Medulla sends signals to respiratory muscles to contract

4) Diaphragm contracts & thorax expands

5) Transpulmonary pressure changes

6) Air moves from AW into alveoli

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Normal Vital Capacity

4.8L

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Normal Inspiratory Capacity

~3.5L

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Normal Functional Residual Capacity

~2.4L

13

Flow

Primary measure of AW volume/obstruction over time

14

PFT Flow Measures

Peak expiratory flow rate; % of FVC exhaled in 1 sec

15

What % of FEV1 & FEF should PFT be?

*FEV1=75-80%

*FEF=25-75%

16

Peak Flow Measurement

Measures max air flow during forced expiration

17

Who are peak flow measurements done on & why?

Pt's w/asthma to monitor AW tone to detect the onset of an attack so drugs can be properly adjusted

18

Body Plethysmography

Approximates body's blood gases if pt can't exhale

19

Pattern for obstructive disorders

Decr flow & incr volume

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Pattern for restrictive disorders

Incr flow & decr vol

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Diffusion Capacity

Amount of air that diffuses through the lungs in 1 breath

22

What is the range for diffusion capacity?

25-30mL CO/min/mmHg

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When will diffusion capacity be low?

W/alveolar capillary membrane destruction

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When will diffusion capacity be high?

Emphysema

25

Indications for PFT

*Measure lung vol, capacities, & flow for baseline & normal values
* Quantify level of lung dysfunction
*Measure pt tx response
*Pre-op screening
*Disability eval

26

O2 will diffuse from alveoli into blood when the PaO2 is in what range?

80-100torr

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CO2 in blood will diffuse into alveoli when the PaCO2 is in what range?

35-45torr

28

Examples ventilatory & oxygenation abns:

*Ventilatory=Obstructive & Restrictive

*Oxygenative=Duffusion Deficit & Shunt (Atelectasis, ARDS)

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Tidal Volume

Air taken in 1 normal breath

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Normal Tidal Volume

~500mL

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Inspiratory Reserve Volume

Max amount of air that can be taken in after a normal inhale

32

Normal inspiratory reserve volume

3L

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Expiratory Reserve Volume

Amount of air that can let out after a normal exhale

34

Normal expiratory reserve volume

1.2L

35

Residual Volume

Air left in lungs after a max exhale (1.2L)

36

What is a capacity test?

Looks at 2+ volumes

37

Define total lung capacity

Amount of air in lungs after a max inhale

38

Examples of restrictive diseases

Kyphoscoliosis
Idiopathic PF
Sarcoidosis
Morbid Obesity

39

ABG's are done to determine:

*Adequacy of ventilations
*Adequacy of oxygenation
*Metabolic status

40

Where are ABG's usually drawn from & why?

Brachial or radial arteries bc they're easy to palpate & aren't near any major vessels

41

What is an Allen's Test?

Pinch off ulnar & radial arteries & release ulnar to check pt's collateral circulation

*<15sec is good

42

Normal pH range

7.35-7.45

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Normal PCO2 range

35-45torr

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Normal PO2 range

80-100torr

45

Normal HCO3 range

22-26meq

46

Normal base excess range

-2 to +2

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Normal SpO2 range

95-100%

48

Values for mild hypoxemia

PO2 of 67-75torr on room air

49

Values for moderate hypoxemia

PO2 of 50-65torr

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Values for severe hypoxemia

PO2 <50torr

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Values for hyperoxia

PO2 >100-120torr

52

What values put a pt in respiratory alkalosis?

PCO2 <35torr

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What values put a pt in metabolic acidosis?

HCO3 <22meq

54

What values put a pt in respiratory acidosis?

PCO2 >45torr

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What values put a pt in metabolic alkalosis?

HCO3 >26meq