Measurement of arterial ammonia has been used as a diagnostic test for hepatic encephalopathy, but obtaining an arterial specimen is an invasive procedure. The aim of this study was to evaluate the ability of a minimally invasive, highly sensitive optical sensing device to detect ammonia in the breath of patients with end-stage liver disease and to evaluate the correlation of breath ammonia levels, arterial ammonia levels, and psychometric testing. Fifteen subjects with liver cirrhosis and clinical evidence of hepatic encephalopathy underwent mini-mental status examination, number connection test, focused neurological examination, and arterial ammonia testing. On the same day, breath ammonia testing was performed using an apparatus that consists of a sensor (a thin membrane embedded with a pH-sensitive dye) attached to a fiberoptic apparatus that detects optical absorption. Helicobacter pylori testing was performed using the 14C urea breath test. A positive correlation was found between arterial ammonia level and time to complete the number connection test (r = 0.31, P = 0.03). However, a negative correlation was found between breath ammonia level and number connection testing (r = −0.55, P = 0.03). Furthermore, no correlation was found between breath and arterial ammonia levels (r = −0.005, P = 0.98). There is a significant correlation between the trailmaking test and arterial ammonia levels in patients with cirrhosis. However, no correlation was found between breath and arterial ammonia levels using the fiberoptic ammonia sensor apparatus in this small study.
encephalopathy cirrhosis ammonia
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Yurdaydin C: Blood ammonia determination in cirrhosis: Still confusing after all these years? Hepatology 38:1308–1309, 2003Google Scholar
Saxena N, et al.: Electrophysiological and neuropsychological tests for the diagnosis of subclinical hepatic encephalopathy and prediction of overt encephalopathy. Liver 22:190–197, 2002CrossRefPubMedGoogle Scholar
Kramer L, et al.: Partial pressure of ammonia versus ammonia in hepatic encephalopathy. Hepatology 31:30–34, 2000CrossRefPubMedGoogle Scholar
Ong J, et al.: Correlation between ammonia levels and the severity of hepatic encephalopathy. Am J Med 114:188–193, 2003CrossRefPubMedGoogle Scholar
Stahl J: Studies of the blood ammonia in liver disease. Ann Intern Med 58:1–22, 1963PubMedGoogle Scholar
Gerron G, et al.: Technical pitfalls in measurement of venous plasma NH3 concentration. Clin Chem 22:663–666, 1976PubMedGoogle Scholar
Conn H: Trailmaking and number-connection tests in the assessment of the mental state in portal systemic encephalopathy. Dig Dis 22:541–550, 1977CrossRefGoogle Scholar
Rikkers L, et al.: Subclinical hepatic encephalopathy: Detection, prevalence and relationship to nitrogen metabolizm. Gastroenterology 75:462–469, 1978PubMedGoogle Scholar
Weissenborn K, et al.: The number connection tests A and B: interindividual variability and use for the assessment of early hepatic encephalopathy. J Hepatol 28(4):646–653, 1998CrossRefPubMedGoogle Scholar
Shimamoto C, Hirata I, Katsu K: Breath and blood ammonia in liver cirrhosis. Hepato-Gastroenterology 47:443–445, 2000PubMedGoogle Scholar
Wakabayashi H, et al.: Measurement of the expiratory ammonia concentration and its clinical significance. Metab Brain Dis 12:161–169, 1997CrossRefPubMedGoogle Scholar