An examination often reveals increased work involved in breathing: nasal flaring may be evident during air intake, and the lips may be pursed (the shape lips make when you whistle) while exhaling.
During a flare of disease, chest inspection reveals contraction of the muscles between the ribs (intercostal retraction) and the use of accessory breathing muscles. The respiratory rate (amount of breaths per minute) may be elevated, and wheezing may be heard through a stethoscope.
A chest X-ray can show an over-expanded lung (hyperinflation), and a chest CAT scan (CT) may show emphysema.
A sample of blood taken from an artery (arterial blood gas) can show low levels of oxygen (hypoxemia) and high levels of carbon dioxide (respiratory acidosis). Pulmonary function tests show decreased airflow rates while exhaling and over-expanded lungs.
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