ABG analysis provides the best clues as to acuteness and severity of disease exacerbation. Renal compensation generally occurs even in chronic CO2 retainers (ie, those with bronchitis); thus, pH usually is near normal. Any pH below 7.3 is typically considered a sign of acute respiratory compromise.
Serum chemistry evaluation is an important component in the workup of patients with COPD. Patients with COPD tend to retain sodium. Additionally, diuretics, beta-adrenergic agonists, and theophylline lower potassium levels, necessitating careful monitoring of serum potassium. Beta-adrenergic agonists also increase renal excretion of serum calcium and magnesium, which may be important when patients have hypokalemia.
Alpha1-antitrypsin levels should be measured in all patients with COPD who are under 40 years of age, as well as in those with a family history of emphysema at an early age, or in patients with emphysematous changes with no smoking history, as this may be an indication of alpha1-antitrypsin deficiency.
For more on the workup of COPD, read here.
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Cite this: Amanda M. K. Godfrey, Zab Mosenifar. Fast Five Quiz: How Much Do You Know About COPD? - Medscape - May 27, 2020.