Spirometry
Spirometry - Related Videos
14:39
Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma
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Cited by 4 •
2010
Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks.
11:38
Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
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Cited by 49 •
2014
The current priority in breast cancer radiotherapy is to reduce cardiac doses without compromising target tissue coverage. The voluntary breath-hold technique described here is a simple, inexpensive solution to this problem and capable of being instituted widely without the need for specialized equipment.
FAQs
The FEV1-to-FVC ratio compares the air expelled during the first second with the total volume forced out. A reduced ratio supports an obstructive pattern because expiration is disproportionately limited, while a reduced FVC with a preserved ratio may be consistent with restriction. Clinicians interpret these values together rather than relying on either measurement alone.
Flow-volume curves show how airflow changes across the inhalation and forced-exhalation maneuver, complementing the numerical FVC and FEV1 results. Their shape can help clinicians recognize patterns associated with obstructive or restrictive lung disease and assess whether the recorded maneuver appears interpretable. This visual information provides context that a single value cannot supply.
A calibrated spirometer is necessary so recorded volumes and flow rates accurately represent the patient’s breathing performance. The patient must also perform a forceful expiration, because incomplete or insufficient effort can lower the measured values and obscure the underlying pattern. Reliable equipment and an appropriately performed maneuver therefore influence the clinical usefulness of the test.
Spirometry distinguishes these patterns by examining the relationship between FEV1, FVC, their ratio, and the accompanying flow-volume curve. Obstructive disease is suggested when the ratio is reduced, whereas restriction is suggested when FVC is reduced with a preserved ratio. These findings identify patterns consistent with disease and guide further clinical assessment.
The patient breathes through a calibrated spirometer and then performs a forceful expiration while the device records exhaled volume and flow. The resulting measurements include FVC and FEV1, which are evaluated together with their ratio and, when available, a flow-volume curve. The clinician then interprets the pattern in the relevant clinical context.
Clinicians use spirometry to support respiratory diagnosis and to assess the severity of an identified or suspected lung problem. It can also help monitor treatment over time, evaluate respiratory fitness before surgery, and contribute to occupational respiratory assessments. Its value comes from linking objective airflow measurements with the patient’s clinical situation.
Repeated testing provides numerical measures that can be compared across clinical evaluations, including FEV1, FVC, and their ratio. Changes in these results may help clinicians assess respiratory status and monitor treatment response over time. Interpretation should consider the associated flow-volume curves and the consistency of test performance so apparent changes are clinically meaningful.