Internal Medicine

0521779407-C02 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 20:53

Chronic Obstructive Pulmonary Disease 341

Arterial Blood Gases

■Early: mild-moderate hypoxemia

■Late: increased hypoxemia; hypercapnia

Sputum

■Commonly colonized with S pneumoniae, H influenza, M catarrhalis

differential diagnosis

■Asthma (distinguished by reversibility)

■Chronic bronchitis (sputum×3mo×≥2 successive y)

■Emphysema (CT or pathologic diagnosis)

■Cystic fibrosis

■Bronchiectasis (CT diagnosis)

■Alpha1-proteinase inhibitor deficiency (<1% of all COPD)

management

■See Global Initiative For Chronic Obstructive Lung Disease, pro-

duced by NIH National Heart, Lung & Blood Institute and World

Health Organization: http://www.goldcopd.com

What to Do First

■Assess severity:

➣Spirometry should be routine

➣Hypoxemia influences survival

General Measures

■Eliminate causative factors (smoking, allergens, occupational expo-

sures)

■Improve airway function (bronchodilators, steroids)

■Prevent or treat infectious exacerbations (vaccines, antibiotics)

■Support end-stage COPD

■Look for comorbid conditions (pneumothorax, CHF, PE, hypophos-

phatemia, hypokalemia)

specific therapy

■Smoking cessation slows loss of lung function

■Oxygen (only treatment proven to prolong life):

➣Indications:

PaO

2 <55; SaO 2 <88%

PaO

2 56–59 or SaO 2 89%+right heart failure or Hct >56%

➣Continuous (20–24 h/d) better than 12 h