Lab 3: Pulmonary Function

Question 1

Classification of Lung Defects

Answer 1

Obstructive lung defects are characterized by difficulty exhaling all the air from the lungs due to narrowed airways,

Restrictive lung defects involve reduced lung expansion and decreased lung volume, caused by stiff lung tissue or chest wall abnormalities, as seen in conditions like pulmonary fibrosis and scoliosis.

Question 2

NORMAL SPIROGRAM

Answer 2

Question 3

What is Forced (FVC)?
What is Slow (FVC)?

Answer 3

• Forced (FVC)
  – Requires proper coaching
  – Three distinct phases
  – Decreased in both obstructive and restrictive diseases
  – Typically 4-5 L in males, 3-4 L in females
• Slow (SVC)
  – Helps avoid air trapping

Question 4

Slow Vital Capacity

Answer 4

Question 5

What is FEV1?

Answer 5

• Maximal volume exhaled during the first second of expiration
• Best indicator of obstructive lung disease
• Flow characteristics of the larger airways
• Best expressed as a percentage of the FVC
  (FEV1/FVC)
  – Should be able to exhale 70% of the vital capacity in the first second
  – Decreased in obstructive disorders

Question 6

Flow Volume Loops

Answer 6

Question 7

Flow Volume Loops

Answer 7

Question 8

Forced Expiratory Flow

Answer 8

slide 18

Question 9

Peak Expiratory Flow Rate (PEFR)

Answer 9

• Maximum flow rate achieved during an FVC
• Used in asthmatics to identify the severity of airway obstruction and guide therapy
• Dependent on patient effort
• Normal value is 10L/sec (600L/min), decreases with age and obstruction

Question 10

Maximum Voluntary Ventilation (MVV)

Answer 10

• MVV – patient breathes as fast and deep as possible for 12-15 seconds
• Tests for overall lung function, ventilatory reserve capacity and air trapping
• Normal = 170L/min
• Decreased in obstructive disorders

Answer 11

Question 12

Exercise Induced Bronchospasm (EIB)

Answer 12

• Acute narrowing of the airways during and after exercise
• Normal lungs vs EIB obstructed lungs can have a similar FVC, but FEV1 will be affected
• Defined as ≥ 10% drop in FEV1 after exercise compared to rest

Question 13

Bronchodilators

Answer 13

Bronchodilators are medications that relax the muscles around the airways, widening the air passages and making it easier to breathe, commonly used to treat conditions like asthma and chronic obstructive pulmonary disease (COPD).slide 27

Question 14

Nitrogen Washout

Answer 14

• Open circuit method
• Patient breathes 100% oxygen while the nitrogen washed out of the lungs is measured
• Assumes 79% of lung volume is nitrogen
• Several “problems” with this test

Question 15

Helium Dilution

Answer 15

• Closed system
• Known volume and concentration of He added and it will be diluted in proportion to the size of the lung volume

Question 16

Diffusion Capacity (DL)

Answer 16

• Represents the gas exchange capabilities of the lungs
• Measures the ability of gas to diffuse across the
  alveolar-capillary membrane using carbon monoxide: DLCO