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Arterial ammonia levels in the management of fulminant liver failure

Authors :
Curry S
Remke S
Little E
Gerkin R
Manch R
Leibowitz A.
Raschke R
Source :
Southwest Journal of Pulmonary and Critical Care, Vol 2, Pp 85-92 (2011)
Publication Year :
2011
Publisher :
Arizona Thoracic Society, 2011.

Abstract

Previous studies have suggested that an arterial ammonia level greater than 150 mmol/L is highly sensitive for predicting subsequent development of cerebral edema in patients with fulminant liver failure. We performed a prospective cohort study to confirm this relationship. We enrolled 22 consecutive patients who presented to our transplant hepatology service with grade 3-4 encephalopathy associated with fulminant liver failure. All patients underwent placement of an intraparenchymal ICP monitor, and every 12 hourly arterial ammonia levels. The prevalence of intracranial hypertension (IHTN) in our population was 95% (21/22 patients), with 82 discrete episodes recorded. The sensitivity of arterial ammonia levels to predict the onset of IHTN was 62% (95% CI: 40.8 to 79.3) at a cut point of 150 mmol/L. Arterial ammonia levels preceding the first intracranial hypertension event were less than 150 mmol/L in 8 of 21 patients (39%). Fifty nine of 82 episodes of IHTN (73%) occurred when arterial ammonia levels were less than 150 mmol/L. We conclude that the arterial ammonia level is not useful in making decisions regarding management related to cerebral edema in patients with fulminant liver failure. In fact, since almost all our study patients with grade III or IV encephalopathy secondary to fulminant liver failure went on to develop intracranial hypertension, our study supports the contention that all such patients might benefit from ICP monitoring regardless of arterial ammonia levels.

Details

Language :
English
ISSN :
21606773
Volume :
2
Database :
OpenAIRE
Journal :
Southwest Journal of Pulmonary and Critical Care
Accession number :
edsair.doajarticles..a27d92b5d514195daeb95df75d2182b1