Flashcards in PFTs & ABGs Deck (79)
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1
Describes amt of O2 bound to hemoglobin in arterial blood
Normal value =
SaO2 (saturation)
Normal = 95-100%
2
Amt of O2 dissolved in arterial blood plasma
Partial pressure of O2 in arterial blood
Normal value =
PaO2
Normal = 80-100mmHg
3
Blood oxygen saturation level
Normal =
Mild respiratory disease =
Supplementary O2 should be used if falls below ________
SpO2
Normal = 94-99%
Mild respiratory disease > 90%
Supplemental O2 if falls below 90%
4
2 conditions of respiratory failure
Hypercarbia
Hypoxemia
5
What is hypercarbia?
Condition of abnormally elevated levels of CO2 levels in blood
Ex: COPD with acute exacerbation
6
What is hypoxemia?
Low O2 in blood
Ex: severe bilateral pneumonia
7
What type of receptor detects too much O2 or too little CO2?
Chemoreceptors (detect changes in chemical concentrations)
8
Where does O2 diffuse from alveoli to arterial blood and CO2 exits?
Alveolar-Capillary Membrane (AC membrane)
9
What is the partial pressure of CO2 called?
(Ventilation & ________)
Normal =
PaCO2 (in artery)
"Little a = artery, big A = alveolar"
Normal = 35-45 mmHg
10
If bulk of O2 is carried bound to hemoglobin, _________ (larger/smaller) amount is what is dissolved in plasma.
What is this called?
Smaller
PaO2
11
Patient not ventilating enough- not blowing off enough CO2
Respiratory acidosis (CO2 goes up, pH goes down)
12
Pt hyperventilating because of pain or anxiety, blowing off too much CO2
Respiratory alkalosis (pH goes up)
13
Too little blood =
Too little oxygen =
Hypoxemia
Hypoxia
14
Carotid arteries and aorta are ___________receptors that respond to changes in blood __________ in normal breathing
Chemoreceptors
Blood chemicals
15
Signals are sent to ________ as PaCO2 and PaO2 change in normal breathing
Medulla
16
Medulla sends signal to respiratory muscles to contract with the _________ nerve in normal breathing
C3-5 phrenic nerve (innervated diaphragm)
17
As thorax expands, the diaphragm ___________ in normal breathing
Contracts
18
Basic pulmonary abnormalities of ventilation (2)
Restrictive defect (neuromuscular, morbid obesity, circumferential burns)
Obstructive defect (asthma, copd)
19
Basic pulmonary abnormalities of oxygenation (2)
Diffusion deficit (pulmonary fibrosis- idiopathic)
Shunt (atelectasis, ARDS)
20
Indications for PFT (5)
1. Measuring lung volumes/capacities/flows (vs baseline and normal values)
2. Quantify level of lung dysfunction
3. Pt response to treatment protocols
4. Pre-op screening
5. Disability evaluation
21
Lung volumes and capacities are a measure of A/W and lung ___________
RESTRICTION
22
Two or more volumes = capacity
What are the 4 volume measures?
1. Tidal volume (VT)
2. Inspiratory reserve volume (IRV)
3. Expiratory reserve volume (ERV)
4. Residual volume (RV)
23
What is tidal volume
normal breath = 500 mls
24
What is inspiratory reserve volume
Volume above normal inhalation = approx 3 L
25
What is expiratory reserve volume
Additional volume exhaled after normal exhalation = 1.2 L
26
What is residual volume
Volume remaining in lungs after complete exhalation = 1.2 L
27
What are the capacities? (4)
1. Total lung capacity (TLC)
2. Vital capacity (VC/FVC/SVC)
3. Inspiratory capacity
4. Functional residual capacity
28
What is total lung capacity (TLC)
IRV + VT + ERV + RV = 5 L (to 6)
29
What is vital capacity (VC/FVC/SVC)
IRV + VT + ERV = 4.8 L
30
What is inspiratory capacity
IRV + VT = 3.5 L
31
What is functional residual capacity
Amt left in lungs after normal respiration = 2.4 L
32
Flows measure __________
OBSTRUCTION
33
Flow = ______/______
Volume/time
34
What does PFT Flow Measure (3)
1. Peak expiratory flow rate (PEFR)
2. % of FVC exhaled in 1 second (FEV1%) = 75-80%
3. Forced expiratory flow (FEF) 25-75% (smaller A/Ws)
35
________ is used to estimate the residual volume (1.2 L) that remains in lungs to keep alveoli open
Body plethysmograph
36
What is a peak flow measurement and what is it for?
Maximum flow during forced expiration, used to monitor asthma patients' airway tone
37
This is a good leading indicator of condition and can help keep pt out of the hospital
Peak flow measurement
38
General pattern of dysfunction for obstructive disorders-
_______ (inc/dec) flows and ______(inc/dec) volumes/capacities
Decreased flows (obstruction) and increased volumes/capacities (air trapping)
39
General pattern of dysfunction for restrictive disorders-
_______ (inc/dec) volumes/capacities and _______ or _______ flows
Decreased volumes/capacities and normal or increased flows
40
True/false
VT, RV, FRC, TLC increase with restrictive pattern
FALSE they DECREASE
41
Why is residual volume in an obstructive disease increased?
B/c increased compliance (COPD- lung loses elasticity)- inability to exhale normally (obstructive pattern has flattened costal angles)
42
What is DLCO and what is normal value?
Diffusion capacity of CO
25-30 mL CO/min/mmHg
43
True/false
Hemoglobin and surface area affect DLCO
TRUE
44
A low diffusion capacity with destruction of alveolar capillary membrane is found in _____ (2)
Emphysema
Pulmonary fibrosis
45
Moderate to severe emphysema- less healthy alveolar capillary membrane = _______ surface area (less/more)
less
46
Does emphysema increase or decrease diffusing capacity
Decrease
47
what is a bleb?
Cavity/hollow
48
Percent change: pre/post bronchodilator --> 15% or more improvement on post-tx suggests ______ (reversible/irreversible) component
Reversible
49
Obstructive sleep apnea, tracheal stenosis, and extrinsic airway compression (tumor) are examples of _____ airway obstruction
Upper/large
50
Kyphoscoliosis and obesity are examples of restrictive diseases of ______________ whereas pulmonary fibrosis and sarcoidosis are restrictive __________ diseases
Chest wall/pleura
Lung
51
What is a low/obstructive FEV1 suggestive of?
Air trapping
52
Indications for ABGs (3)
1. Determine adequacy of ventilation
2. Determine adequacy of oxygenation
3. Determine metabolic status
53
Physics of ABGs involves this physics law
Dalton's Law of Partial Pressures
54
Site from which to draw an ABG
Radial artery (adults)
Near surface, easy to palpate, collateral circulation through ulnar artery, not near large veins
55
What is the Modified Allen's Test for?
Pass/fail- <15 seconds to flush is good indication of collateral circulation (hand should turn pink again in 3-5 seconds)
56
What is the representation of the following numbers? (What ABGs)
7.40/41/92/23/1
PH/PCO2/PO2/HCO3/BE
57
What are the normal ABG values?
PH = 7.35-7.45
PCO2 = 35-45 torr
PO2 = 80-100 torr
HCO3 = 22-26 meq
BE = -2 --> +2
SO2 = 95-100%
58
Order to evaluate ABGs
1st- pH: normal, acidosis, alkalosis
2nd- PCO2: normal, acidosis, alkalosis
3rd- HCO3 and BE: normal, acidosis, alkalosis
4th- oxygenation status: normal, hypoxemia, hyperoxygenated
59
Values for pH acidosis and alkalosis
< 7.35 acidosis
>7.45 alkalosis
60
Values of PaCO2 acidosis and alkalosis
>45 respiratory acidosis
<35 respiratory alkalosis
61
HCO3 acidosis/alkalosis values
<22 metabolic acidosis
>26 metabolic alkalosis
62
Base Excess (BE) acidosis/alkalosis
< -2 metabolic acidosis
> +2 metabolic alkalosis
63
Assessment of PCO2-
If > 45 torr, what is happening with patient?
Acidosis- CO2 retention, hypoventilation
64
If PCO2 < 35 torr, what is happening with pt?
Hyperventilation (alkalosis)
65
What is compensatory response in respiratory acidosis?
Increase PCO2, Increase HCO3
66
What is compensatory response in respiratory alkalosis?
Decrease PCO2, decrease HCO3
67
What is compensatory response in metabolic acidosis?
Decreased HCO3, decreased PCO2
68
What is compensatory response in metabolic alkalosis?
increased HCO3, increased PCO2
69
Hypoxemia if PO2 is _______ torr
<75-80
70
Mild hypoxemia
Moderate hypoxemia
Severe hypoxemia
Mild: 67-75 torr on room air
Moderate: 50-65 torr
Severe: <50 torr
71
Hyperoxia
PO2 > 100-120 torr
72
Interpret the following:
7.28- PCO2 58- HCO3 26- BE +2- PO2 65
Uncompensated respiratory acidosis w/ mild hypoxemia
73
Interpret the following-
7.22- PCO2 36- HCO3 17- BE -6- PO2 98
Uncompensated metabolic acidosis w/ normal oxygenation
74
What is FRC and what is its purpose?
- Equilibrium point between lung and chest recoil
- Maintains ABGs to normal level
75
In obstructive diseases, FVC ______.
In restrictive diseases, FVC _______.
Obstructive- Normal or decreased
Restrictive- Decreased
76
In obstructive diseases, FEV1/FVC% ______.
In restrictive diseases, FEV1/FVC% ________.
Obstructive- decreases
Restrictive- normal/increases
77
How are capacity values determined?
By age, sex, and height
78
What is a normal PFT value?
80-110% of predicted
79
