Spirometry

Question 1

Inspiratory reserve + Tidal volume=

Expiratory reserve volume + Residual volume=

Answer 1

Inspiratory reserve + Tidal volume= Inspiratory capacity

Expiratory reserve volume + Residual volume= Functional residual capacity

Question 2

Tidal volume + Inspiratory reserve volume + Expiratory reserve volume =

Answer 2

Tidal volume + Inspiratory reserve volume + Expiratory reserve volume = Vital capacity

Question 3

Atmospheric pressure =

Plural pressure at rest =

Answer 3

zero

negative

Question 4

Define Transpulmonary pressure: Ptp

Answer 4

Palv-Ppl

Question 5

What happens during inspiration in the lungs?

Hint: start with muscles cnx and how that changes volumes and pressures

Answer 5

Diaphragm and intercostals cnx–> thorax EXpands–> Ppl becomes more Subatmospheric (more negative)–> will cause INCREASE of Transpulmonary pressure –> Lungs expand–> Palv becomes subatmospheric–> air into alveoli

Question 7

We must genenerate a ____ pressure in the alveoli to get air to rush in

Answer 7

Negative pressure (does this after lungs expand)

Question 8

What determines airflow, particularly during expiration?
Flow =

Answer 8

Palv-Patm /airway resistance

Thus RESISTANCE big determining factor and changes across lengthand diamter of airway

Question 9

What can you deduce from this graph about the size of bronhci and the resistance?

Answer 9

Key is HIGH resistance in the medium sized bronchi around 5-10 generations; less of a total cross sectional area. As we get to higher generations, resistance much lower

Question 10

At low lung volumes, airway resistance is ______

Answer 10

HIGH, increasing lung volume increases x-section and decreases resistance.

Resistance and xsection have inverse relationship

Question 11

The tip of this curve is what:

What is it defined by?

Answer 11

Point of zero airflow

Ptp = Ppl

Question 12

When looking at this graph, what does the slope represent?

Ptp =

Answer 12

Compliance

Ptp = Palv = Ppl

Question 13

What do we see in emphysema and fibrosis in a Vital capacity vs pressure graph?

Answer 13

Empysema requires less pressure generated to get to TLC

In fibrosis, you need a larger change in pressure to generate change in volume

Question 14

Why do lines A, B and C meet at around 4 liters of expired air?

Answer 14

Past a certain point, expiration is effort independent, doesn’t matter how hard you blow out.

Question 15

What is the pattern of the pressure in the alveoli as it moves towards bronchus?

Answer 15

We see pressure inside alveoli dissipates

starts at +40 while the pressure exerted against it is +30…

as we get closer to bronchus, pressure decreases and is more likely to collapse

Question 16

Indications for PFTs

Answer 16

Indications for PFTs
• Diagnostic: Symptoms, signs, abnormal lab tests
• Assess the effects of diseases and therapies
• Screening: Smokers, occupational exposures, preoperative risk, disability, prognosis

START WITH SPIROMETRY

Question 17

You’re on rotations and your attending calls you over and shows you a spirometry and asks you a dx… what’s your repsonse?

Answer 17

tell her you need the pt history as well.. can’t dx with spirometry alone!

Question 18

What is going on in the Volume Time curve

Answer 18

Just showing us that the peak is air you are expiring. You reach a peak after 1 sec and slowly decreases after that. Most people reach residual volume at 6 seconds

Question 19

Any structures that are affecting airflow inside the chest or intra-thoracic will affect _____

Structures outiside the chest (extra-thoracic) will affect _____

Answer 19

expiration

inspiration

Question 20

At ____the inspiratory and expiratory flow rates should be about the same

Answer 20

50% vital capacity

Question 21

Focusing on the expiratory phase (part on top) how is obstructive disease different then normal?

Restrictive?

Answer 21

Obstructive has a scalloped expiratory flow… result of air trapping. You can’t blow air out as fast.

Restrictive: you cannot bring in as much air, no issue on expiration

Question 22

Which image shows fixed upper airway obstruction with flow limitation and flattening of both the inspiratory and expiratory limbs of the flow-volume loop.

Answer 22

One on far left

Question 23

Could patient with COPD have a loop pattern like the one of the far left?

Answer 23

The diagram shows fixed upper airway obstruction as flow is limited in both inspiration and expiration.

This immediately rules out intrathoracic pathology – COPD and pulmonary fibrosis.

Question 24

panel shows dynamic (or variable, nonfixed) extrathoracic obstruction with flow limitation and flattening of the inspiratory limb of the loop.

Answer 24

Middle loop = Vairable extrathoracic issue

Question 25

panel that shows dynamic (or variable, nonfixed) intrathoracic obstruction with flow limitation and flattening of the expiratory limb of the loop.

Answer 25

Right panel = variale intrathoracic; determine by large intrathoracic airways

Question 26

When interpreting Spiromety: Look only at : Always look at this first:

Answer 26

* Look only at FEV1/FVC ratio, FEV1, and FVC * Always look at the **FEV1/FVC ratio first**

Question 27

• FEV1/FVC must be close to\_\_\_\_% of predicted to be “normal” - anything outside the\_\_\_\_% confidence interval is low

Answer 27

100% 95%

Question 28

Spirometry interpretation: • A NOT-LOW ratio is seen in\_\_\_\_\_\_ ventilatory function and\_\_\_\_\_ processes • A LOW ratio indicates\_\_\_\_\_\_\_ processes

Answer 28

normal and restrictive obstructive

Question 29

In order for a spirometry test to be within normal limits, what 2 things must be there?

Answer 29

* FEV1/FVC ratio (FEV1/VC%, FEV1/VC ratio) is normal * AND VC (FVC) is normal

Question 30

FEV1/FVC ratio (FEV1/VC%, FEV1/VC ratio) is normal in the range of:

Answer 30

(normal range can be .70 to .87, depending on demographics of patient)

Question 31

VC (FVC) is normal when it's in the range of:

Answer 31

(usually greater than or equal to 80% of predicted- within the 95% confidence level

Question 32

What disease process do we see on this spirometry?

Answer 32

Shows airway obstruction: could be caused by stuff like inflmmation or bronchoconstriction: mucus/fibrous damage could do it too.

Question 33

What is the significance of using a spirometry test to tell if someoneh as obstructive diseaes?

Answer 33

Because FEV1 is effort dependent so that will IG look simular to normal, but as exhalation continues, it is effort independent and depends on smaller structures, such as bronchioles and alveoli, which ar damaged in obstructive diseases

Question 34

If the FEV1/FVC Ratio is Low • Degree of airway obstruction is based upon the percent of predicted FEV1 • % Predicted FEV1 \>99% : • % Predicted FEV1 70 - 99% : • % Predicted FEV1 60 - 69% :

Answer 34

* % Predicted FEV1 \>99% Physiologic Variant * % Predicted FEV1 70 - 99% Mild * % Predicted FEV1 60 - 69% Moderate

Question 35

* % Predicted FEV1 50 - 59% : * % Predicted FEV1 34 - 49% : * % Predicted FEV1 \< 34%: * “OBSTRUCTIVE VENTILATORY DEFECT”

Answer 35

* % Predicted FEV1 50 - 59% Moderately Severe * % Predicted FEV1 34 - 49% Severe * % Predicted FEV1 \< 34% Very Severe * “OBSTRUCTIVE VENTILATORY DEFECT”

Question 36

Bronchodilator Responsivity • Assess for all patients with spirometry showing a : • Assess for all patients suspected of :

Answer 36

low FEV1/FVC ratio • asthma or chronic obstructive lung disease • A significant response to a bronchodilator is shown when the FVC or FEV1 increases at least 12% and 200mls

Question 37

What determines if a bronchodilatory response occured?

Answer 37

• A significant response to a bronchodilator is shown when the FVC or FEV1 increases at **least 12% AND 200mls**

Question 38

Obstructive Ventilatory Pattern • Large conducting airways: • Peripheral airways: • Pulmonary parenchymal disease:

Answer 38

• Large conducting airways: tumors, foreign bodies • Peripheral airways: asthma, chronic bronchitis, cystic fibrosis • Pulmonary parenchymal disease: emphysematous changes from cigarette smoking

Question 39

Restrictive Ventilatory Defect • Interstitial lung disease: • Pleural disease: • Chest wall disease: • Extrathoracic conditions:

Answer 39

sarcoidosis, collagen vascular diseases, pulmonary fibrosis pleural effusion kyphosis, neuromuscular disorders obesity

Question 40

What do changes from normal in restrctive ventilatory defects on spirometry?

Answer 40

See the overall shape is normal but the FVC is low

Question 41

Normal FEV1/FVC Ratio and a Decreased FVC • Interpret cautiously from spirometry-should obtain lung volumes We may want to think right away this is Restrictive disease, but \_\_\_\_\_\_\_ is the true hallmark of a restrictive ventilatory defect

Answer 41

**• Reduced TLC**

Question 42

* % Predicted TLC 70% to LLN : * % Predicted TLC 60 to 69% : * % Predicted TLC \< 60% :

Answer 42

* % Predicted TLC 70% to LLN Mild * % Predicted TLC 60 to 69% Mod * % Predicted TLC \< 60% Mod Severe * “RESTRICTIVE VENTILATORY DEFECT”

Question 43

If cannot obtain lung volumes when determining restrictive disease is present or not, grade FVC via the

Answer 43

obstructive FEV1 criteria

Question 44

If the FEV1/FVC Ratio is Not Low and TLC is Low and You are Following the _____ to Assess Restriction

Answer 44

FVC

Question 45

If the FEV1/FVC Ratio is Not Low and TLC is Low and You are Following the FVC to Assess Restriction • Degree of restriction is based upon the percent of predicted FVC • % Predicted FVC 70 - 79% : • % Predicted FVC 60 - 69%: • % Predicted FVC 50 - 59% : • % Predicted FVC 34 - 49% : • % Predicted FVC \< 34% :

Question 46

Look at **Shape** of the Flow Volume Loop • Beware of a flattened inspiratory curve • Check the **FEF50/FIF50 ratio** • FEF50/FIF50 1.00 or less : • FEF50/FIF50 \> 1.00 : FEF50/FIF50 A little \> 1 :

Answer 46

Normal if 1.0 or less \>1.0 is variable extrathoracic airway obstruciton a little \<1 : Fixed Extrathoracic airway obstruction

Question 47

Guidelines for acceptibility in Spirograms

Answer 47

* Free from artifacts: Cough, early termination * Good start: Extrapolated volume is \<5% of FVC or 0.15 L, whichever is greater or time to PEF is \<120 ms * Satisfactory exhalation: 6 sec of exhalation and/or a plateau in the volume-time curve

Question 48

Repeatability guidelines on spirometry

Answer 48

Repeatability • After three acceptable spirograms: Are the two largest FVCs within 0.2 L of each other? Are the two largest FEV1s within 0.2 L of each other? • If both of these criteria are not met, test until: Both are met or a total of 8 tests • Save the 3 best maneuvers

Question 49

Examples of unacceptable spirograms

Answer 49

extrapolated volume, hesitation while exhaling, cough, exhalation not complete