Home » Spirometry



Spirometry is one of the lung function tests; they are a useful investigation in treating patients with respiratory disease or respiratory weakness secondary to neurological damage. They aid in diagnosis, help monitor response to treatment, and can guide decisions about further treatment Treatment and intervention [1]. A spirometer can measure all lung volumes except residual volume.

  • Investigation of patients with symptoms/signs/investigations suggestive of lung disease (eg, cough, wheezing, dyspnea, crackling, or abnormal chest x-ray)
  • Monitoring the progression and response to therapy in patients with known pulmonary disease (eg, interstitial fibrosis COPD asthma or pulmonary vascular disease)
  • Investigate patients with conditions that may have respiratory complications, such as connective tissue disease or neuromuscular disease
  • Preoperative evaluation before abdominal surgery for pneumonectomy or cardiothoracic surgery.
  • Evaluation of patients at risk for pulmonary disease (eg, exposure to pulmonary toxins such as radiopharmaceuticals or environmental or occupational exposures)
  • Surveillance after lung transplantation to assess for acute rejection infection or bronchiolitis obliterans [1].
  • Aneurysm
  • Haemoptysis of unknown origin
  • Pneumothorax
  • Cardiovascular instability Recent myocardial infarction or pulmonary embolism
  • Acute illness affecting test performance, such as nausea or vomiting
  • recent chest or abdominal surgery
  • Eye surgery
  • Pleural Effusion
  • Post-MI.[1][2][3]


  • The equipment used must be calibrated before spirometry is performed, or at least checked at the beginning of the session. Calibration procedures vary by device. Read the instructions associated with your spirometer for more information. Some gauges need to be returned to If the calibration fails, refer the manufacturer for repair. It is considered optimal to check spirometry values once a week using a biological control (a healthy person working on your team) [3].
Patient positioning:
The correct measurement posture is as follows:
  • Upright sitting: as long as sitting upright with no restrictions [4], there is a difference in the amount of air the patient exhales from a sitting and standing position [4], and the standing position is better than the supine position [5]
  • Feet flat on the floor, legs uncrossed: Leg poses don’t use the abs.
  • Loosen tight-fitting clothing
  • Dentures that usually stay in: Unless the dentures are very loose, it’s best to have some structure in the mouth area.
  • Using a chair with arms: When exhaling maximally, the patient becomes dizzy and may shake or faint.

In a hospital setting, your patient may not be able to sit in a chair, so the patient’s position (usually supine) should remain the same and recorded for future testing [3].


There are many different techniques that can be used to perform spirometry. Most commonly, however, the patient inhales as deeply as possible, then exhales as hard as possible as quickly as possible, and continues breathing until there is no more air. PEF was obtained from FEV1 and FVC manipulations.

Encouragement makes a big difference, so don’t be afraid to raise your voice to encourage the patient, especially near the end of the procedure. The patient needs to continue blowing until no more air is coming out. Some patients, especially those with obstructive disease, may find it difficult Exhale completely while working hard. [3]


Acceptable operations are defined as follows:

  • Explosive priming (no hesitation or S-curve) with back-extrapolated volumes <150 mL (Figure 1)[1]
  • This operation is performed with maximum inhalation and maximum exhalation.
  • No glottic closure or cessation of airflow (eg, by hesitation or occlusion of the mouthpiece) occurred during the maneuver.
  • Inhale without coughing (especially in the first second) during traces or evidence of leaks.
The best FEV1 and FVC can be obtained from different exercises.

Reproducibility may be problematic: forced exhalation causes bronchoconstriction, so there must be ≥30 seconds between maneuvers. In some patients, especially those with asthma, it may be necessary to hold it for a few minutes [3].

Measurement definitions
The measurement is defined as follows [3]:

Forced expiratory volume in one second (FEV1) The volume of air forcefully exhaled after the first full inhalation. Forced Vital Capacity (FVC) The volume of air forcefully exhaled after a full inhalation. The ratio of the two (FEV1/FVC) This calculation allows Identify obstructive or restrictive ventilatory defects. FEV1/FVC <70%, where FEV1 decreases more than FVC, suggests an obstructive lesion. FEV1/FVC >70%, with a decrease in FVC more than FEV1 seen in restrictive pathology. vital capacity (VC) the maximum amount of air that can be breathed Exhalation exhaled when blowing as fast as possible Peak expiratory flow (PEF) The maximum flow that can be exhaled when blowing at a steady rate



Lorem ipsum dolor sit amet, consectetur adipisci

  1. ↑ Jump up to:1.0 1.1 1.2 1.3 Ranu, H., Wilde, M., Madden, B. Pulmonary Function Tests. The Ulster Medical Journal, 2011; 80(2), 84–90.
  2.  Cooper BG. An update on contraindications for lung function testing. Thorax. 2011 Aug;66(8):714-23. doi: 10.1136/thx.2010.139881.
  3. ↑ Jump up to:3.0 3.1 3.2 3.3 3.4 3.5 Moore VC. Spirometry: step by step. Breathe. 2012; 8(3):232-40.
  4.  Patel AK, Thakar HM. Spirometric Values in Sitting, Standing and Supine Position. J Lung Pulm Respir Res. 2015; 2(1): 00026. DOI: 10.15406/jlprr.2015.02.00026
  5.  Melam G, Buragadda S, Alhusaini A, Alghamdi M, Alghamdi M, Kaushal P. Effect of Different Positions on FVC and FEV1 Measurements of Asthmatic Patients. Journal of physical therapy science.2014; 26(4) 591-593. 10.1589/jpts.26.591.
  6.  Armando Hasudungan Lung Function – Lung Volumes and Capacities Available from: https://www.youtube.com/watch?v=9VdHhD1vcDU. Accessed on 4/11/19
  7.  Armando Hasudungan Understanding Spirometry – Normal, Obstructive vs Restrictive Available from:https://www.youtube.com/watch?v=YwcNbVnHNAo. Accessed on 4/11/19.
  8.  The European Lung Foundation Spirometry: how to take a lung function test Available from: https://www.youtube.com/watch?time_continue=4&v=6kbgZWS5wH0 Accessed on 4/11/19
  9.  CANVent Ottawa Pulmonary Function Assessment in Neuromuscular Diseases and Spinal Cord Injury Available from:https://www.youtube.com/watch?v=78vfDmufbVU Accessed on 4/11/19

ng elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Leave a Comment

Your email address will not be published. Required fields are marked *

تواصل معنا
السلام عليكم 👋
كيف يمكنني مساعدتك ?