Investigation for COPD

Investigation for COPD (similar to asthma)

Pulmonary function test or Lung function test
-Measure the size of your lungs
-how much air you can breathe in and out
-how fast you can breathe air out
-how well your lungs deliver oxygen to your blood.

Type of Pulmonary function test

1) Spirometry (main)
-how much air you breathe in and out and how fast you blow it out.
-peak expiratory flow rate (PEFR): amount of air you can blow air out as quickly as possible
-forced expiratory volume in 1 second (FEV1): amount of air you can blow out in 1 second.
- FVC: forced vital capacity
- A diagnosis of airflow obstruction can be made if the FEV1/FVC less than 0.7 (i.e. 70%) and FEV1 less than 80% predicted

2) Peak flow meter
- How well air moves out of your lungs.

3) Lung Volume Measurement
- Size of your lungs and how much air you can breathe in and out
- During the test, you sit inside a glass booth and breathe into a tube that's hooked to a computer.Sometimes you breathe in nitrogen or helium gas and then blow it out. The gas you breathe out is then measured to test how much air your lungs can hold.
- Help diagnose lung tissue scarring or a stiff and/or weak chest wall.

4) Lung Diffusion Capacity
- How well oxygen passes from your lungs to your bloodstream.
- You breathe in a gas through a tube. You hold your breath for a brief moment and then blow the gas out.
- Abnormal test results: loss of lung tissue, emphysema (a type of COPD), very bad scarring, or problems with blood flow through the body's arteries.

Chest X Ray / Computerized tomography (CT) scan
- Can show emphysema (one of the causes of COPD)
- Show sign of COPD
- To rule out other causes

Blood test

1) Arterial Blood Gas Analysis
- How well your lungs are bringing oxygen into your blood and removing carbon dioxide.
-find out whether you may need supplemental oxygen therapy.

2) Full blood count
- To identify anaemia or polycythaemia

Sputum Examination
-Analysis of the cells in your sputum can help identify the cause of your lung problems and help rule out some lung cancers.


Additional investigations (tbc):
-Alpha-1 antitrypsin: if early onset, minimal smoking history or family history
-Transfer factor for carbon monoxide (TLCO): to investigate symptoms that seems disproportionate to the spirometric impairment
-ECG and echocardiogram: to assess cardiac status if features of cor pulmonale


References:
http://www.nhlbi.nih.gov/health/dci/Diseases/Copd/Copd_Diagnosis.html
http://www.nhlbi.nih.gov/health/dci/Diseases/lft/lft_whatare.html
http://www.nhlbi.nih.gov/health/dci/Diseases/lft/lft_types.html
http://www.mayoclinic.com/print/copd/DS00916/DSECTION=all&METHOD=print
http://www.patient.co.uk/doctor/Diagnosing-COPD.htm