Plethysmography

Plethysmograph is a diagnostic tool that is used to measure flow or pressure. Body plethysmography test involves sitting inside an airtight box and breathing to a particular volume. Blood pressure cuffs are placed around your arm and leg. The patient undergoing plethysmography test must remove clothing on arm and leg and refrain from smoking at least half hour prior to the test. The consequent expansion and decompression of the chest volume allows physicians to rule out any blockages in the limbs as it measures systolic blood pressure. Any abnormal readings can be indicative of arterial occlusive disease, vascular disease or blood clots or even deep venous thrombosis. This test is also referred to as arterial plethysmography and is a vital pulmonary function test. Plethysmography is often used to determine bronchial reactions to histamine or metacholine. But this test is not as accurate as arteriography.

PFT

PFT - Pulmonary Function Test refers to one or different types of tests that are conducted on a patient to assess the condition of the lungs and their efficiency in transferring oxygen to the blood. PFT can help diagnosing the cause of 'shortness of breath' and confirm lung diseases like Emphysema, Bronchitis and Asthma. PFT aids in measuring occupational hazards of exposure to contaminants such as asbestos or radon. It helps monitoring of disease treatment. These tests are mandatory before any major lung surgery. However, PFT is not given to patients who had a recent heart attack or has a history of heart disease.

Spirometry is a vital PFT that measures how well the lungs exhale. This diagnostic test is prescribed for patients suffering from asthma or COPD. This tests involves breathing into a mouthpiece that is connected to a spirometer. The amount of air and rate of exhalation are measured over a specific time.

Peak Expiratory Flow Rate - PEFR meter is a handheld device that measures the rate of exhalation in a patient. This PEFR test results can vary depending upon a number of factors - age, height and sex. So peak flow meters are mostly useful for monitoring the medications of some Asthma patients.

Lung volume measurement test can aid detection of restrictive lung diseases. Such patients are often unable to inhale normal volumes of air due to inflammation or scarring of lung tissue. This PFT can be done as a body plethysmograph.

Gas diffusion test measures the amount of oxygen and other gases that are absorbed into your body from your lungs.

Inhalation challenge test aids in identifying possible allergens that can cause asthma or severe respiratory allergy. Other tests to measure lung function include residual volume, gas diffusion tests, body plethysmography, inhalation challenge tests, and exercise stress tests.

Patients scheduled for PFT must restrain from use of bronchodilators or inhaler medications for few hours prior to the test. Patients are advised not to eat a heavy meal or smoke for a few hours prior to the PFT. Typical normal values for pulmonary function tests are based on the age, height, ethnicity, and sex of the person being tested. Factors such history of smoking, wheezing and obesity can affect results of PFT. Pulmonary function tests are not advised for patients who have recently suffered heart attack.