Breath and blood ammonia in liver cirrhosis

Hyperammonemia causes dysfunction of multiple organs in patients with cirrhosis, including hepatic encephalopathy. Blood ammonia concentrations are monitored with respect to disease progression and efficacy of treatment. Fetor hepaticus, the characteristic breath odor in hepatic encephalopathy has called little quantitative attention to breath ammonia. We studied the dynamics of ammonia metabolism in cirrhosis in terms of the relationship between breath and blood ammonia.

Breath and blood ammonia levels were measured simultaneously in 20 cirrhotic patients and in 10 healthy volunteers. Breath ammonia was measured using ammonia electrodes in collected expired air. Helicobacter pylori serum antibody titers were also measured, since the organism produces ammonia.

Blood ammonia correlated positively with breath ammonia in patients with cirrhosis. Breath ammonia levels were significantly higher in cirrhotic patients (0.745 ppm) than in controls (0.278 ppm), and higher in cirrhotic patients with hyperammonemia (0.997 ppm) than in those without (0.558 ppm). Breath and blood ammonia decreased together with treatment of hyperammonemia. H. pylori seropositivity was 20% in controls, 27.3% in cirrhotic patients with normal blood ammonia, and 66.7% in those with hyperammonemia.

Breath ammonia measurement may be useful in diagnosis, treatment assessment, and follow-up in hepatic encephalopathy.