Lung Function Test

Lung functions tests are mainly diagnostic tools that measure the various functions of the human lung. These tests help determine how your lungs are performing with regard to how well they process the air that we take in and if they are distributed well through the body. Lung volume or lung capacity is also measured through lung function tests. Other tests also help determine any physiological abnormalities of the lungs.

Lung function tests also help in the diagnosis of various respiratory disorders such as asthma and bronchitis. Conditions such as chest pain and shortness of breath may also be explored through spirometry. These tests are also used to determine the effects of medication on the lungs as also to examine the lungs of those who have been affected adversely by environmental factors or work hazards (coal mine workers or those who work with chemicals for example). In many cases, fitness for surgery or a procedure might be adjudged by a lung function test. Lung function tests help in checking for conditions like COPD (Chronic Obstructive Pulmonary Disease), sarcoidosis, asthma and lung tissue scarring.

Spirometry

Spirometry is the most commonly used test to measure and evaluate lung functions, while there are several other tests that pertain to more specific diagnostic needs. In the spirometry test, lung function is observed as the patient breathes into the spirometer. The patient's nostrils are usually clipped and a tight mouth piece is used. The patient will be monitored by a trained professional and asked to breathe at various paces in order to measure various test parameters and also the capacity of the lungs.

Peak Flow Meter: This hand-held device aids in tracking breathing and is especially helpful to those suffering wheezing and asthma.

Lung diffusion capacity: This lung function test helps in gauging how effectively oxygen is passed from the lungs to the bloodstream.

Lung volume measurement: This breathing test indicates the amount of air left in your lungs after breathing out.

Wheezing

Wheezing is a characteristic high pitched whistling sound made while breathing, a primary symptom of a chronic respiratory disease - Asthma. It is not uncommon in those with respiratory allergies, especially during the hay fever season. Sometimes, other respiratory infections could be accompanied by mild wheezing, especially when acute Bronchitis is experienced. It is also noticed in those with heart failure and Chronic Obstructive Pulmonary Disease COPD. While most commonly wheezing occurs during breathing out, it can sometimes also be related to breathing in.

Causes of Wheezing

Narrowing of airways results in breathing difficulty and wheezing. There could be several causes for narrowing of airways including inflammation from asthma, infection, allergic reaction or a physical obstruction such as tumor or foreign body inhalation. Among the possible causes of wheezing include allergies, insect bite or medication or pollen, pet dander, dust, foods, Bronchiolitis, bronchitis, childhood asthma, epiglottitis, GERD, heart failure, lung cancer, pneumonia, sleep apnea, smoking and vocal cord dysfunction.

Respiratory Syncytial Virus (RSV) Infection is also known as Bronchiolitis - inflammation of the bronchioles which in turn refer to the the narrow airways which branch from bronchi to the air sacs called as alveoli. This RSV infection largely affects infants and children.

To determine the cause of wheezing, your doctor will ask questions about any symptoms that triggers it. If you have no history of lung disease and develop wheezing after eating a certain food or in a certain season, respiratory allergy is suspected. The doctor checks the lungs with a stethoscope to find out where the wheezing is and how bad it is. During a first time evaluation, the doctor performs a spirometry - breathing test, and also a chest X ray.

Sometimes other blood tests and procedures become necessary depending upon the health condition. In case it is allergic wheezing, then a variety of tests to determine the allergies including dermatological examinations are done.

Wheezing problems

Wheezing is accompanied by difficult breathing, rapid breathing and briefly bluish skin color. Emergency care must be sought if wheezing begins suddenly after being stung by a bee, while taking medication, or eating an allergy-causing food or after choking on a small object or food.

Wheezing in infants

In case of a baby, wheezing could be due to cold or problematic asthma. But it is not always clear if the infant has asthma. It is essential to get a firm diagnosis and make sure that the child gets treated for any breathing problems. In some infants, Bronchiolitis could occur due to a viral infection. The airways swell making breathing difficult. As the airway of an infant is small, infants are easily affected. Wheezing could result due to Bronchiolitis, which may develop into asthma in later life. Otherwise a child could be born with a tendency to wheeze and therefore could be prone to bronchiolitis and asthma. Less common reasons for wheezing in infants include inhalation of a foreign object or piece of food into the lungs, premature birth, insufficiently developed airways and cystic fibrosis.

Treatment options

A variety of treatments are available to help alleviate wheezing. However, regular monitoring by a doctor is a must, especially if the patient has asthma, chronic allergies, severe bronchitis, emphysema or chronic obstructive pulmonary disease. In some, wheezing can be relieved by certain medications or by using an inhaler. Some might need insertion of a breathing tube into the throat. The doctor may recommend some or all of the following to reduce inflammation and open up the airways obstructing breathing to stop wheezing:

• A bronchodilator inhaler, which can act fast to dilate constricted airways.
  
• An inhaled Corticosteroid
  
• A long-acting bronchodilator and Corticosteroid combination
  
• A controller pill for asthma to reduce airway inflammation
  
• A non-sedating antihistamine pill or a prescription nasal spray for nasal allergies, which are available over the counter.

Self-care measures to ease wheezing

Moisturize the air by either using a humidifier or a steamy shower or just sit in the bathroom with the door closed while running a hot shower. This is simply because moist air can help relieve mild wheezing in some cases.

Drinking fluids can relax the airway and loosen up sticky mucus in the throat.

Active or passive smoking can worsen a cough and hence it is best to avoid tobacco.

Emergency

Normally, mild wheezing that accompanies bronchitis disappears when the infection subsides. But in case of breathing difficulty, she needs to rush to the doctor who can administer the following:

• A shot of epinephrine to open up the clogged respiratory passages.
  
• Oxygen
  
• Frequent nebulizer to ease breathing
  
• A mechanical ventilator to help you breathe

It is for the doctor to determine the cause of wheezing and then treat the patient for the specific cause.

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.