Overview
Clinical Meaning
Spirometry measures lung volumes and airflow to diagnose and classify respiratory disease.
PMHNP
PMHNP
Spirometry measures lung volumes and airflow to diagnose and classify respiratory disease. Key measurements: FEV1 (forced expiratory volume in 1 second — the volume of air exhaled in the first second of a forced expiration after maximal inspiration), FVC (forced vital capacity — the total volume of air exhaled during a complete forced expiration), and the FEV1/FVC ratio. Normal FEV1/FVC ratio is ≥0.70 (or above the lower limit of normal [LLN] adjusted for age, sex, height, and race using GLI-2012 reference equations). Obstructive pattern: FEV1/FVC <0.70 (or <LLN); air trapping due to airway narrowing; FEV1 is disproportionately reduced compared to FVC. Causes: asthma, COPD, bronchiectasis. Classified by FEV1 % predicted: GOLD criteria for COPD: GOLD 1 (mild) ≥80%; GOLD 2 (moderate) 50-79%; GOLD 3 (severe) 30-49%; GOLD 4 (very severe) <30%. Restrictive pattern: FEV1/FVC is normal or increased (≥0.70); both FEV1 and FVC are proportionally reduced; lung volumes are decreased. Requires full pulmonary function testing (PFT) with lung volumes to confirm: TLC (total lung capacity) <80% predicted. Causes: interstitial lung disease, chest wall abnormalities, neuromuscular disease, obesity. Mixed pattern: features...
Unlock full lesson + practice questions
4 more sections with scenarios, priorities, and review drills.
Final rapid review before practice
Next study step
Finish the lesson first, then choose a focused activity to apply what you just reviewed.
Continue studying
Sign in to save progress on this lesson.
Unlock the interactive lesson quiz with a plan that includes this PMHNP pathway. You can still explore topic-filtered questions from the bank hubs below.