Objective Nitric oxide (NO) production is enhanced in patients with liver cirrhosis (LC). Although most patients with mild LC have neither dyspnea nor platypnea, they might have mild oxygenation abnormalities due to intrapulmonary vasodilatation caused by increased NO. We investigated whether oxygenation abnormalities, such as hypoxemia and orthodeoxia, are present in patients with mild LC.
Methods We investigated 148 consecutive patients with biopsy-proven chronic liver diseases such as CH (noncirrhotic chronic hepatitis) (n=46), LC(A), LC(B), and LC(C) (LC Child's A, B, and C) (n=18, 51, 33, respectively). The oxygen saturation by pulse oxinietry (SpO
2) in the supine and upright positions was determined in patients and controls (normal subjects, n=29). The change in SpO
2 on standing was defined as ΔSpO
2. NO output in exhaled air was measured in 16 patients.
Results Four patients [two LC(B) and two LC(C)] had hypoxemia (supine SpO
2≤94% and/or upright SpO
2≤94%). Although there was no intergroup difference in the supine SpO
2 or the upright SpO
2, the ΔSpO
2 decreased [control, +0.2±0.6%; CH, +0.1±0.9%; LC(A), -0.3±0.8%; LC(B), -0.2±0.9%; LC(C), -0.5±1.1%; mean±SD; p=0.005] with worsening liver disease, and the prevalence of desaturation on standing (ΔSpO
2≤-1%) increased [control, 7%; CH, 20%; LC(A), 33%; LC(B), 35%; LC(C), 42%; p=0.01]. The NO output was inversely correlated with ΔSpO
2 (r=-0.66, p=0.006).
Conclusions Desaturation on standing is present in one-third of normoxemic patients with mild LC of Child's A, and is associated with the severity of liver disease. This postural desaturation is correlated with the exhaled NO, which suggests that intrapulmonary vasodilatation may play some role in this phenomenon.
(Internal Medicine 41: 435-140, 2002)
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