The British Thoracic Society (BTS) published criteria for grading the severity of chronic obstructive pulmonary disease (COPD).
(1) clinical state
(2) spirometric measurements
none or minimal
cough with or without sputum production
present on exertion
some, variable wheezing
with mild exertion
• Abnormal clinical signs include wheezing, cyanosis, peripheral edema, polycythemia, lung overinflation ("barrel chest").
FEV1 as percent of expected
Arterial Blood Gas
60 - 79%
40 - 59%
variable hypoxemia but not hypercapnic
hypoxemia with or without hypercapnia
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