May provide an adjunctive means of diagnosing various forms of COPD (eg, lower lobe disease may suggest alpha1-antitrypsin (AAT) deficiency
Electrocardiography can help establish that hypoxia is not resulting in cardiac ischemia and that the underlying cause of respiratory difficulty is not cardiac in nature
Greater sensitivity than standard chest radiography
Stage IV (very severe): FEV1 less than 30% of predicted or FEV1 less than 50% and chronic respiratory failure
A long, narrow heart shadow
Stage III (severe): FEV1 30-49% of predicted
High specificity for diagnosing emphysema (outlined bullae are not always visible on a radiograph)
Serum potassium – Diuretics, beta-adrenergic agonists, and theophylline act to lower potassium levels
Increased retrosternal air space
Patients with mild COPD have mild to moderate hypoxemia without hypercapnia
Stage I (mild): FEV1 80% or greater of predicted
Radiographs in patients with chronic bronchitis show increased bronchovascular markings and cardiomegaly
Pulse oximetry, combined with clinical observation, provides instant feedback on a patient's status
May help the clinician determine whether surgical intervention would benefit the patient
ABGs provide the best clues as to acuteness and severity of disease exacerbation
Rapidly tapering vascular shadows accompanied by hyperlucency of the lungs
As the disease progresses, hypoxemia worsens and hypercapnia may develop, with the latter commonly being observed as the FEV1 falls below 1 L/s or 30% of the predicted value
pH usually is near normal; a pH below 7.3 generally indicates acute respiratory compromise
Chronic respiratory acidosis leads to compensatory metabolic alkalosis
Measure AAT in all patients younger than 40 years, in those with a family history of emphysema at an early age, or with emphysematous changes in a nonsmoker (also see Alpha1-Antitrypsin Deficiency).
Hematocrit – Patients with polycythemia (hematocrit greater than 52% in men or 47% in women) should be evaluated for hypoxemia at rest, with exertion, or during sleep
Flattening of the diaphragm
Stage II (moderate): FEV1 50-79% of predicted
Sputum evaluation will show a transformation from mucoid in stable chronic bronchitis to purulent in acute exacerbations