Navigate Up

Full Library - A-Z Index


Print This Page

Lung plethysmography

Lung plethysmography is a test used to measure how much air you can hold in your lungs.

Alternative Names

Pulmonary plethysmography; Static lung volume determination; Whole-body plethysmography

How the Test is Performed

You will sit in a small, airtight room known as a body box. You will breathe or pant against a mouthpiece. Clips will be put on your nose to shut off your nostrils. Depending on the information your doctor is looking for, the mouthpiece may be open at first, and then closed.

You will breathe against the mouthpiece in both the open and closed positions. The positions give different information to the doctors. As your chest moves while you breathe or pant, it changes the pressure and amount of air in the room and against the mouthpiece. From these changes, the doctor can get an accurate measure of the amount of air in your lungs.

Depending on the purpose of the test, you may be given some medication before the test.

How to Prepare for the Test

Let your doctor know if you are taking any medications, especially ones for breathing problems. You may have to temporarily stop taking certain medications before the test.

Wear loose clothes that allow you to breathe comfortably.

Avoid smoking and heavy exercise for 6 hours before the test.

Avoid heavy meals before the test. They can affect your ability to take deep breaths.

How the Test will Feel

The test involves rapid and normal breathing, and should not be painful. You may feel short of breath or light-headed. You will be monitored at all times by a technician.

The mouthpiece may feel uncomfortable against your mouth.

If you have trouble in tight spaces, the box might make you anxious. But it is clear and you can see outside at all times.

Why the Test is Performed

The test is done to see how much air you can hold in your lungs during rest. It helps your doctor determine if a lung problem is due to damage to the lung structure, or a loss of the lungs' ability to expand (get bigger as air flows in).

Although this test is the most accurate way to measure how much air you can hold in your lungs, it is not often used because of its technical difficulties.

Normal Results

Normal results depend on your age, height, weight, ethnic background, and gender.

What Abnormal Results Mean

Abnormal results point to a problem in the lungs. This problem can be due to a breakdown of the lung structure, a problem with the chest wall and its muscles, or a problem with the lungs being able to expand and contract.

Lung plethysmography will not find the cause of the problem. But it helps the doctor narrow down the list of possible problems.

Risks

  • Anxiety from being in the closed box
  • Dizziness
  • Light-headedness
  • Shortness of breath

References

Hegewald MJ, Crapo RO. Pulmonary function testing. In: Mason RJ, Broaddus VC, Martin TR, et al, eds. Murray and Nadel’sTextbook of Respiratory Medicine. 5th ed. Philadelphia, PA: Saunders Elsevier; 2010:chap 24.

Reynolds HY. Respiratory structure and function: mechanisms and testing. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 85.

Updated: 8/25/2014

Denis Hadjiliadis, MD, Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.


©  UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences
Supplemental content provided by A.D.A.M. Health Solutions. All rights reserved.

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

For UPMC Mercy Patients: As a Catholic hospital, UPMC Mercy abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices and/or procedures that contradict the moral teachings of the Roman Catholic Church.

© UPMC
Pittsburgh, PA, USA UPMC.com