Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
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J. Cereb. Blood Flow Metab. · Jan 2006
Comparative StudyPersistent arterial hyperammonemia increases the concentration of glutamine and alanine in the brain and correlates with intracranial pressure in patients with fulminant hepatic failure.
In this prospective study of patients with fulminant hepatic failure (FHF), we tested the hypothesis that arterial hyperammonemia results in cerebral accumulation of the osmotic active amino acids glutamine and alanine, processes that were expected to correlate with intracranial pressure (ICP). By using in vivo brain microdialysis technique together with ICP monitoring in 17 FHF patients (10 females/7 males; median age 49 (range 18 to 66) years), we found that arterial ammonia concentration correlated to brain content of glutamine (r=0.47; P<0.05) but not to alanine. A persisting high arterial ammonia concentration (above 200 micromol/L) characterized patients who developed high ICP (n=8) while patients who did not experience surges of increased ICP (n=9) had a decline in the ammonia level (P<0.05). ⋯ Also arterial ammonia concentration correlated to ICP (r=0.73, P<0.01). To conclude, this study shows that persistence of arterial hyperammonemia is associated with profound changes in the cerebral concentration of glutamine and alanine. The elevation of brain glutamine concentration correlated to ICP in patients with FHF.