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Understanding Spirometry: A Key Tool in Pulmonary Health

Written by Stream Creative | Nov 5, 2024 3:29:09 PM

Spirometry evaluates overall lung function and offers insights into a patient’s respiratory health. As a diagnostic tool, spirometry allows physicians and medical professionals to diagnose, monitor and manage pulmonary conditions, ranging from asthma and chronic obstructive pulmonary disease (COPD) to restrictive lung disorders. This guide will explain the fundamental principles of spirometry, interpretive strategies and the significance of spirometry in the clinical setting.

What is Spirometry?

Spirometry is a non-invasive, fundamental pulmonary function test that measures lung volume and airflow, accurately assessing lung functionality.

During a spirometry test, a patient inhales deeply and then exhales forcefully into a spirometer, which records the volume of air expelled and the exhalation rate. 

Spirometry provides physicians and medical professionals with quantifiable lung capacity and airflow data. This helps create a diagnosis for treatment and respiratory management plans.

Spirometry provides a range of diagnostic advantages in detecting and managing respiratory conditions:

  • It provides pulmonologists with the “gold standard” for COPD diagnosis.
  • It helps with the early detection of several other respiratory conditions.  
  • It can assist healthcare providers in identifying abnormalities in lung function years before symptoms become clinically apparent.
  • It can monitor disease progression over time, ideal for long-term pulmonary care.


Read our full PDF spirometry overview here covering the full history, diagrams of lung function, sample data and more! 

How Spirometry Works

Key metrics from a spirometry test include Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1) and the FEV1/FVC ratio.
  • FVC (Forced Vital Capacity) refers to the total air volume that can be forcefully exhaled after a deep breath. It helps determine the lungs' overall capacity and is used to identify conditions that restrict lung volume.
    FEV1 (Forced Expiratory Volume in one second) measures the air volume a person can forcefully expel in the first second of exhalation. This is a crucial indicator of airway function, particularly in diagnosing obstructive lung diseases like COPD and asthma.
  • FEV1 (Forced Expiratory Volume in one second) measures the air volume a person can forcefully expel in the first second of exhalation. This is a crucial indicator of airway function, particularly in diagnosing obstructive lung diseases like COPD and asthma.
  • FEV1/FVC ratio compares the amount of air exhaled in the first second to the total exhaled volume. A lower ratio typically indicates airflow obstruction, as seen in COPD, while a normal or high ratio might point to restrictive lung diseases, such as pulmonary fibrosis and sarcoidosis.

Take a
look at our video library now to see spirometers in action. 

 Indications for Spirometry

Spirometry is integrated into several clinical settings, such as diagnosing respiratory conditions like asthma, COPD and other lung diseases. For patients with symptoms such as shortness of breath, chronic cough or wheezing, spirometry is often the first step in assessing lung function. Spirometry also confirms diagnoses where airflow limitation plays a central role. 

In addition to its diagnostic role, spirometry aids in clinical decision-making.

  • Spirometry is often used in preoperative evaluations. Patients' lung functions are assessed before surgical procedures to identify those at risk of complications during and after the procedure. 
  • In occupational health, spirometry is essential for monitoring workers exposed to harmful dust, chemicals or fumes, where regular lung function tests can catch early signs of damage before symptoms appear. 
  • Spirometry is also part of routine health checks for smokers over 40, as early detection of lung disease can lead to more effective intervention.

 
Routine monitoring with spirometry is vital in managing chronic lung diseases. It helps track disease progression, adjust treatment plans and assess how well therapies work. This helps physicians and healthcare professionals provide the most appropriate and effective care at every stage.

Preparing Patients for Spirometry

Accurate spirometry results require proper patient preparation. Patients should avoid smoking for several hours before the test, ideally refraining for 24 hours. In addition, they should not use bronchodilators or other respiratory medications before the spirometry test unless otherwise instructed by their doctor. Both activities can influence the results. It's also important that patients wear loose clothing to avoid restricting their breathing during the test.

During a spirometry test, the patient will be upright, either in a chair or standing. A nose clip is often used to prevent air from escaping through the nose during testing. The patient will be instructed to take a full, deep breath and then exhale as forcefully and completely as possible into the spirometer mouthpiece. The patient must continue exhaling for at least six seconds to ensure a complete measurement of their lung capacity. Once this is complete, the patient will take another deep breath, this time inhaling fully to measure inspiratory capacity.

The test may need to be repeated several times to ensure consistent results. Breaks can occur between attempts, if necessary. Depending on the patient’s condition, bronchodilators may be administered, and the test may be repeated to assess how well the lungs respond to medication.

Learn more about available professional spirometers with this helpful overview

Interpreting Spirometry Results

Accurate interpretation of spirometry results is essential for diagnosing a range of respiratory conditions. The patient’s VC and FEV1 results will be compared to predicted values based on age, gender, height and ethnicity.

Normal results indicate that lung function is within the expected range, with airflow and lung capacity performing as they should for a healthy individual.
 
Abnormal results point to potential issues with lung function. Obstructive lung diseases, such as asthma or COPD, usually present with a reduced FEV1 and a lower-than-normal FEV1/FVC ratio, indicating difficulty in expelling air from the lungs. Restrictive lung diseases like pulmonary fibrosis often show a normal or near-normal FEV1/FVC ratio but a reduced FVC, suggesting limited lung expansion and reduced total lung capacity.
 
Some patients may exhibit a “mixed pattern,” which indicates the presence of obstruction and restriction. This can make interpretation more complex, reflecting impaired airflow and reduced lung volume. Identifying these patterns will help determine the underlying condition and tailor the appropriate treatment plan.

Benefits of Spirometry for Patient Outcomes

Spirometry use enables earlier detection of lung problems before they become symptomatic, which can result in improved patient outcomes. Identifying respiratory conditions like asthma or COPD in their early stages provides the opportunity for earlier medical interventions that can prevent further lung damage and improve long-term prognosis. Catching lung issues early can also lead to more effective treatments and better patient quality of life.
 
In addition to diagnosis, spirometry plays a crucial role in monitoring the efficacy of treatment over time. By regularly measuring lung function, healthcare providers can track how well a patient's treatment plan works. If the results indicate little to marginal improvement, medication or therapy adjustments can be made to manage the condition better. Ongoing monitoring ensures that care plans are tailored to the patient's needs as conditions evolve, ultimately leading to more precise and effective care.

Did you know you can monitor lung function anywhere, anytime? See how that’s possible. 

Advancements in Spirometry Technology

Recent innovations in spirometry technology are focused on improved accessibility and effectiveness of lung function testing. Advanced technology has transformed spirometry into a tool that can be used beyond clinical environments. 

  • Portable and wireless spirometers now allow point-of-care testing in various settings, expanding from primary care offices to patients’ homes. This advancement now provides for remote monitoring of patients, which gives healthcare providers the ability to track patients' lung health without requiring frequent in-person visits.
  • Modern spirometers are equipped with wireless connectivity, which enables real-time data transmission to clinicians. Physicians and healthcare professionals can complete real-time analysis of lung function results. This allows for adjustment of treatment plans that respond to changes in patient condition. The improved device convenience and usability levels also improves patient adherence to and comfort level with regular testing. Spirometers have become easier to use and integrate into daily routines. 

Spirometry remains an objective and reliable cornerstone of respiratory care. Its ability to diagnose, monitor and manage respiratory disorders makes it an effective tool in caring for respiratory patients. 
 
By integrating routine spirometry testing into clinical practice, healthcare providers can improve patient outcomes and quality of life, ensuring timely interventions and more personalized treatment plans. As spirometry technology improves, its greater accessibility and ease of use continue to reinforce its value as a vital respiratory care tool.

Interested in discovering your potential ROI from Pulmonary Function Testing? Use our new Reimbursement Calculator to input your estimated weekly patient numbers and explore how much earning potential your practice could generate from pulmonary function testing.


At MIR, we provide spirometers and oximeters tailored to the diverse needs of professionals and patients, enabling both precise and accurate measurement of respiratory functions and simple, intuitive home monitoring.

MIR is internationally recognized for the uniqueness of its patented products and proud to be certified across the world for meeting the highest quality requirements, including: 

  • CE marked under Medical Device Regulation - MDR (Europe)

  • Food and Drug Administration - FDA (United States of America)

  • Health Canada (Canada)

  • National Medical Products Administration - NMPA (China)

  • Agência Nacional de Vigilância Sanitária - ANVISA (Brazil)

  • Comisión Federal para la Protección contra Riesgos Sanitarios - COFEPRIS (Mexico)

Contact MIR USA for more information on how our innovative professional and personal spirometers can help you and your patients monitor lung health.