Test 3 - PFTs Flashcards
(20 cards)
Spirometer
Equipment to measure lung volumes
Respirometer
Equipment to measure minute volume
Body Plethysmography
Equipment to measure lung volumes and thoracic gas
Helium Dilution
Takes 4 - 7 minutes, is complete once equilibrium is reached
Which tests are performed to measure Residual Volume?
Helium Dilution
N2 washout
Body Plethysmography
How do you know bronchodilator is effective?
FEV1 is increased by 12% AND > 200 mL
How is resistance measured?
PLETHYSMOGRAPHY
Interrupter method
Forced Oscillation Technique
How is compliance measured?
Spirometer
Other volumetric device
Pressure transducer
What are the hazards of bronchoprovocation?
Severe bronchoconstriction
Hyperinflation
Severe coughing
DLCO
Diffusing Capacity of the Lungs
Measures lungs ability to exchange oxygen with mixed venous blood
Nitrogen Washout
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
How wide should the heart be on chest X-ray?
< 50% of the width of the X-ray
Computed Tomography (CT)
Slices, 2-3 mm, Hi-res is thinner
Head, mental status, tumor, hemorrhage, lymph node vs tumor, need to see more from Xray
Ventilation Perfusion Scan (V/Q)
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
Positron Emission Tomography (PET)
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
Carboxyhemoglobin (COHb)
< 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
Hemoglobin (Hb)
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
Methemoglobin (metHb)
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
Obstructive
Decreased FEV1
Decreased FVC
Decreased FEV1/FVC < 70% predicted
Restrictive
Decreased FEV1
Decreased FVC
Normal or Increased FEV1/FVC
