CHEST CLINICAL COPD & ASTHMA IMMERSION PROGRAM - AUGUST 14, 2024-Pulmonary Function Testing

Pulmonary Function Testing - Kopca

Pdf Summary

Pulmonary function testing (PFT) assesses lung performance and aids in diagnosing respiratory conditions. It's an essential tool for measuring lung volumes and capacities, primarily using spirometry and other lung volume methods. Spirometry evaluates airflow, determining how much air and how fast it enters and exits the lungs. Key metrics include Forced Expiratory Volume in one second (FEV1) and Forced Vital Capacity (FVC). <br /><br />Interpretation of results helps identify airflow obstruction or restriction. A normal FVC with a low FEV1/FVC ratio indicates obstruction, while a low FVC with a normal FEV1/FVC ratio suggests restriction. The flow-volume loop is a graphical representation of inhalation and exhalation, crucial for diagnosing these patterns.<br /><br />Reference values for PFT are compared against individuals of similar age, sex, and height. Historically, race or ethnicity has been considered, but the Global Lung Initiative (GLI) recommends a universal reference set, which includes standards for spirometry, diffusing capacity, and lung volumes.<br /><br />To ensure accuracy, spirometry results must meet validity criteria, such as being free from artifacts, and demonstrating good start and exhalation efforts. Repeatability is verified by achieving at least three acceptable efforts with close agreement between the two highest FEV1 and FVC values.<br /><br />The highest acceptable values for FVC and FEV1 should be recorded, even if obtained from different maneuvers, to report the FEV1/FVC ratio accurately. The flow-volume loop with the largest sum of FEV1 and FVC should also be documented.<br /><br />Grading the severity of impairment follows interpretive strategies based on Z-scores, with scores ranging from normal (greater than -1.65) to severe (less than -4). This structured approach ensures standardized reporting and aids in consistent diagnosis and treatment of pulmonary conditions.

Keywords

Pulmonary function testing

PFT

lung performance

spirometry

FEV1

FVC

airflow obstruction

flow-volume loop

Global Lung Initiative

Z-scores