PFT

Question 1

Factors that affect PFT testing; What happens if you get an error?

Answer 1

• Caffeine, sedatives, smoking, large meal, pregnancy, cognition, cooperation and motivation
• Error requires you to restart the entire process over

Question 2

Normal Lung Volume and Capacities

Answer 2

TV: 500 cc
IRV: 2000 cc
ERV: 1500 cc
RV: 1500 cc

Question 3

FVC Def

Answer 3

• Forced Vital Capacity
• The volume of air that can be maximally forcefully exhaled

Question 4

FEV1

Answer 4

1 second expiratory volume

Question 5

FEF 25-75

Answer 5

Forced expiratory flow between 25% -75% [middle 50% of expiration] [L/sec]

Question 6

PEF

Answer 6

Peak expiratory flow rate [L/sec]

How fast you can blow air out

Question 7

Normal Ranges: FVC, FEV1, FEV1/FVC, FEF 25-75

Answer 7

FVC: Greater than 80% predicted volume
FEV1: Greater than 80% predicted voume (80-120% Range)
FEV1/FVC: Greater than 70%
FEF 25-75: Greater than 60% [Up to 130%]

Question 8

Restrictive Disorders: Lung volumes may show:

Answer 8

• Decreased FVC, FEV1 and TLC

Question 9

Restrictive Disorders Steps/Criteria

Answer 9

A reduction in all lung volumes

Steps:
1. FEV1/FVC Ratio: <70% predicted? No
2. FVC: Less than 80% predicted? Yes

Question 10

Obstructive Disorder Criteria

Answer 10

• Reduced Flow Rates
• Depending on the area obstructed will change FEV1 (upper) and FEF (lower) values
• FEV1/FVC Ratio: <70% predicted? Yes
• FEV1 is decreased out of proportion to FVC which is why the ratio decreases (Increase in TLC and RV)

Question 11

What would an obstructive lung disorders PFT look like?

Answer 11

• Scoop Out
• Initial exhalation is reduced; looks like ice cream scooped it out

Question 12

FEV1 Stages:

Answer 12

• Mild (Stage 1): Greater than or equal to 80% predicted
• Moderate: 50-80% predicted
• Severe: 30-50% predicted
• Very Severe (Stage 4): <30% or <50% with respiratory failure

Question 13

COPD vs Asthma: What value must change?

Answer 13

• FEV1.

Does it change with inhaled bronchodialator?
* No: COPD, remains <0.7 FEV1/FVC ratio, FEV1 does not improve
* Yes: Increase 12% FEV1 improvement = reversible

Question 14

Draw out diagram of the process of differentiating PFTs

Answer 14

Question 15

Obstructive or Restrictive? How severe?

Answer 15

• FEV/FVC is less than 70% predicted
• FVC is not less than 80% = Obstructive
• Severity = Moderate (50-80% FEV1)

Question 16

What is DLCO? What does it measure?

Answer 16

• Measures ability of lungs to transport inhaled gas [Carbon monoxide & Helium] from alveoli to pulmonary capillaries
• Measure how much CO and Helium goes in and how much in exhaled air.
  – Anemia, COPD
• This is due to carbon monoxide having such a high affinity for Hb