Testing: DLCO, Table 1 Conditions associated with abnormal DLCO

Reduced DLCO

Reduced DLCO

Inspiratory muscle weakness

Anemia

Reduced effort

Pulmonary emboli

Valsalva maneuver

Cigarette smoking (reduced Hb binding sites and increased CO back pressure)

Increased inspired fraction of oxygen (patient receiving supplemental oxygen)

Emphysema

Interstitial lung disease

Pulmonary edema

Pulmonary vasculitis

Pulmonary hypertension

Increased DLCO

Increased DLCO

Decreased inspired fraction of oxygen (altitude)

Polycythemia

Müller maneuver

Left-to-right shunt

Exercise

Pulmonary hemorrhage

Supine position

Asthma

Obesity