Test 3 - PFTs

Question 1

Spirometer

Answer 1

Equipment to measure lung volumes

Question 2

Respirometer

Answer 2

Equipment to measure minute volume

Question 3

Body Plethysmography

Answer 3

Equipment to measure lung volumes and thoracic gas

Question 4

Helium Dilution

Answer 4

Takes 4 - 7 minutes, is complete once equilibrium is reached

Question 5

Which tests are performed to measure Residual Volume?

Answer 5

Helium Dilution
N2 washout
Body Plethysmography

Question 6

How do you know bronchodilator is effective?

Answer 6

FEV1 is increased by 12% AND > 200 mL

Question 7

How is resistance measured?

Answer 7

PLETHYSMOGRAPHY
Interrupter method
Forced Oscillation Technique

Question 8

How is compliance measured?

Answer 8

Spirometer
Other volumetric device
Pressure transducer

Question 9

What are the hazards of bronchoprovocation?

Answer 9

Severe bronchoconstriction
Hyperinflation
Severe coughing

Question 10

DLCO

Diffusing Capacity of the Lungs

Answer 10

Measures lungs ability to exchange oxygen with mixed venous blood

Question 11

Nitrogen Washout

Answer 11

Measures FRC

• Pt. breathes 100% O2
• Expired N2 concentration monitored
• Continues for 7 minutes or until all N2 is washed out of lungs
• Washout is complete when N2 concentration < 1.5% for 3 consecutive breaths

Question 12

How wide should the heart be on chest X-ray?

Answer 12

< 50% of the width of the X-ray

Question 13

Computed Tomography (CT)

Answer 13

Slices, 2-3 mm, Hi-res is thinner

Head, mental status, tumor, hemorrhage, lymph node vs tumor, need to see more from Xray

Question 14

Ventilation Perfusion Scan (V/Q)

Answer 14

Not common anymore
CT w/Dye contrast is more common
Mainly for PE
2 Types
Radiotaupe medicine inhaled, hold breath
Radiotaupe IV
Nuclear Medicine for this procedure

Question 15

Positron Emission Tomography (PET)

Answer 15

Not used very often, checks for tumors, FDG-18 (sugar water) injected, attracts to active tumors forms “hot spots” Benign tumors will not attract, used to assess tumor, malignancies, post-chemo, 1st time diagnosis

Question 16

Carboxyhemoglobin (COHb)

Answer 16

< 3% (non-smokers)
5% - 10% Smokers
Every gram of Hb chemically bound to a molecule other than O2 is equivalent to an absolute reduction of 1g/dL of circulating Hb. *COHb of 40% would be 9 g/dL instead of 15 g/dL
Shifts oxyhemoglobin dissociation curve left
Inhibits unloading of oxygen at tissues

Question 17

Hemoglobin (Hb)

Answer 17

1 gram of Hb can carry 1.34 ml of O2
avg Hb content = 15 g/dL x 1.34 = 20.1 mL/dL
This is the average O2 carrying capacity of the blood

Question 18

Methemoglobin (metHb)

Answer 18

Iron in the heme group is oxidized from ferrous to ferric state
Incapable of binding with O2
CO poisoning occur at metHb levels 20% to 50% range

Question 19

Obstructive

Answer 19

Decreased FEV1
Decreased FVC
Decreased FEV1/FVC < 70% predicted

Question 20

Restrictive

Answer 20

Decreased FEV1
Decreased FVC
Normal or Increased FEV1/FVC