Updated: 12/29/2021

Pulmonary Function Tests

0%
Topic
Review Topic
0
0
Topic
Images
https://upload.medbullets.com/topic/120664/images/flowvolumenormal.jpg
https://upload.medbullets.com/topic/120664/images/obsturction.jpg
https://upload.medbullets.com/topic/120664/images/restrictive.jpg
https://upload.medbullets.com/topic/120664/images/flowvolume.jpg
  • Snapshot
    • A 23-year-old man presents to the emergency department with weakness. He states his legs were weak yesterday but now he is also having trouble breathing. He recently recovered from a diarrheal illness. The patient's forced vital capacity is significantly reduced and he is subsequently intubated (Guillain Barre syndrome).
  • Introduction
    • Clinical definition
      • spirometry
        • measures volume of expired air during forceful and complete exhalation
          • forced vital capacity (FVC)
            • total exhaled volume after a maximal inspiration
          • forced expiratory volume in 1 second (FEV1)
            • the volume exhaled in the first second of maximal expiration
          • FEV1:FVC ratio
            • low = obstructive disease
              • air can not get out quickly
              • concerning for obstructive disease (such as asthma)
            • normal/high = restrictive disease
              • no obstruction of airway
              • concerning for restrictive disease (such as pulmonary fibrosis)
        • flow-volume loops
          • plot out spirometry findings
            • normal
            • obstructive disease
            • restrictive disease
      • bronchoprovocation challenge
        • administration of bronchospastic agent (such as methacholine) followed by spirometry
          • can aid in diagnosis of asthma
  • Pulmonary Function Tests
    • MetricsDefinition
      Obstructive
      Restrictive
      Elasticity
      • Ease of recoil after lungs have expanded
      Compliance
      • Ease of alveoli expansion
      Volumes
      Minute volume
      • Volume of air expired in 1 minute
      • =/↓
      Residual volume (RV)
      • Air left in lung after max expiration
      Total lung capacity (TLC)
      • All the air in the lung = vital capacity + residual volume
      Tidal volume
      • Volume of air breathed in and out for a normal breath
      Vital capacity
      • Total volume exhaled after full inspiration.
      Spirometry
      Forced expiratory volume (FEV1) normal = 4L
      • Volume expelled in one second
      • =/↓
      Forced vital capacity (FVC)
      normal = 5L
      • Entire volume that can be expelled
      • =/↓

      (FEV1)/FVC
      normal = 80%

      • Considered best screen, values of less than 50% correlate with postoperative pulmonary complications.
      • =/↑

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Flashcards (0)
Cards
1 of 0
EXPERT COMMENTS (0)
Private Note