lung volumes, capcities, normal flow volume loops definitions

• related: PFT and lung functions
• tags: #permanent #pulmonary

---

Links to this note

• PFT and lung functions
  • lung volumes, capcities, normal flow volume loops definitions
• airflow obstruction happens first in distal airways
  • FEF\_{25-75%} are sometimes used to describe this decrease in small airway flow between 25% and 75% of exhaled FVC (lung volumes, capcities, normal flow volume loops definitions). However the measurements are widely variable and thus not used.¹

• TLC: average person, 6 L total
• RV: 1 L residual volume
• TV: quiet breathing, 2.5 - 3L
• Inspiratory Reserve Volume: volume inhaled after inspiration TV
• ERV: same with expiration TV
• FRC: functional residual capacity, volume left after TV expiration

• VC: everything but residual volume

• IRV
• TV
• ERV
• RV
• bottom 2: FRC
• top 2: IC
• top 3: VC
• all 4: TLC

^{1 2}

Footnotes

1. https://mgcdiagnostics.com/images/uploads/documents/FlowVolumeLoop_poster_18x24_2024.pdf ↩ ↩²

2. Get Valid Spirometry Results Every Time ↩