Edema and its mechanism....?

y does edema of the feet occur in a person with COPD?...and can you also tell me the mechanism of how that occurs?..
and what are edema 1+, edema 2+ and edema 3+?..
and how is it that restelessness occur in a COPD patient?
Thanks!

Extracellular Fluid Volume Expansion
ECF volume expansion is caused by an increase in total body Na content. It typically occurs in heart failure, nephrotic syndrome, and cirrhosis. Clinical features include weight gain, edema, and orthopnea. Diagnosis is clinical. Treatment aims to correct volume expansion and its cause.
Chronic obstructive pulmonary disease is partially reversible airflow obstruction caused by an inflammatory response to inhaled toxins, often cigarette smoke. 伪1-Antitrypsin deficiency and various of occupational exposures are less common causes in nonsmokers. Symptoms are productive cough and dyspnea that develop over years; common signs include decreased breath sounds, prolonged expiratory phase of respiration, and wheezing. Severe cases may be complicated by weight loss, pneumothorax, right heart failure, and respiratory failure. Diagnosis is based on history, physical examination, chest x-ray, and pulmonary function tests. Treatment is with bronchodilators, corticosteroids, and, when necessary, O2 and antibiotics. About 50% of patients die within 10 yr of diagnosis.
Please see the web pages for more details on Edema and COPD.

people with COPD could get heart failure which results in the backup of fluids. the levels of edema, +1 and so on indicates the depth of the pitting in milimeters. So if you very lightly press your finger in the edemous area and it pits (finger print stays) they measure the depth, the higher the number the more severe. Maintaining adequate fluids will help, meaning drinking enough water, and taking any duiretics as prescribed