Breath ammonia testing for diagnosis of hepatic encephalopathy.

Abstract

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.

• Authors: Suja DuBois, Sue Eng, Renuka Bhattacharya, Steve Rulyak, Todd Hubbard, David Putnam, David J Kearney
• Journal: Digestive diseases and sciences (Dig Dis Sci) Vol. 50 Issue 10 Pg. 1780-4 (Oct 2005) ISSN: 0163-2116 [Print] United States
• PMID: 16187173 (Publication Type: Clinical Trial, Comparative Study, Journal Article)

Chemical References

• Ammonia
• Urea

Topics

• Ammonia (metabolism)
• Breath Tests (instrumentation)
• Equipment Design
• Female
• Hepatic Encephalopathy (diagnosis, metabolism)
• Humans
• Male
• Middle Aged
• Predictive Value of Tests
• Reproducibility of Results
• Trail Making Test
• Urea (metabolism)