spiromeeter

A spirometer is a medical device used to measure the volume of air that a person can inhale and exhale, and how quickly air can be moved in and out of the lungs. The term is often used interchangeably with spirometry, which refers to the lung function test performed with the device. Spirometry provides objective data on lung function that can aid in diagnosing and monitoring respiratory conditions.

There are several types of spirometers, including volume-based, flow-based, and turbine or ultrasonic devices. Modern spirometers are typically connected to computers or display screens and may include pneumotachographs or other flow sensors. The test produces measurements such as forced vital capacity (FVC), the amount of air forcefully exhaled after a full inhalation; forced expiratory volume in one second (FEV1); and the ratio of FEV1 to FVC (FEV1/FVC). Some tests also record peak expiratory flow (PEF) and other flow-volume parameters.

Results are interpreted by comparing patient values to predicted normal ranges based on age, sex, height, and ethnicity. A reduced FEV1/FVC ratio often indicates obstructive disease (for example, asthma or COPD), while a reduced FVC with a normal or high FEV1/FVC ratio may suggest a restrictive pattern. Spirometry is used for diagnosing conditions, assessing severity, guiding treatment decisions, and monitoring response to therapy. It is typically performed during a controlled, effortful breath-hold maneuver and repeated to ensure reproducibility.

Maintenance involves regular calibration, cleaning, and use of disposable mouthpieces to prevent infection. While generally safe, spirometry should be performed under professional supervision, especially in patients with acute illness, recent chest surgery, or other contraindications.