Analysis of cerebral blood flow and intracranial hypertension in critical patients with non-hepatic hyperammonemia

作者：Larangeira Alexandre Sanches; Tanita Marcos Toshiyuki; Dias Marcos Antonio; Ferreira Filho Olavo Franco; Alvares Delfino Vinicius Daher; Queiroz Cardoso Lucienne Tibery; Carvalho Grion Cintia Magalhaes

来源：Metabolic Brain Disease, 2018, 33(4): 1335-1342.

DOI：10.1007/s11011-018-0245-z

• Hyperammonemia
• Transcranial Doppler ultrasonography
• Optic nerve
• Intracranial hypertension
• Critical care

Hyperammonemia in adults is generally associated with cerebral edema, decreased cerebral metabolism, and increased cerebral blood flow. The aim of this study was to evaluate the association between non-hepatic hyperammonemia and intracranial hypertension assessed by Doppler flowmetry and measurement of the optic nerve sheath. A prospective cohort study in critically ill patients hospitalized in intensive care units of a University Hospital between March 2015 and February 2016. Clinical data and severity scores were collected and the Glasgow coma scale was recorded. Serial serum ammonia dosages were performed in all study patients. Transcranial Doppler evaluation was carried out for the first 50 consecutive results of each stratum of ammonemia: normal (< 35 mu mol/L), mild hyperammonemia (35 mu mol/L and < 50 mu mol/L), moderate hyperammonemia (50 mu mol/L and < 100 mu mol/L), and severe hyperammonemia (100 mu mol/L). The measurement of the optic nerve sheath was performed at the same time as the Doppler examination if the patient scored less than 8 on the Glasgow coma scale. There was no difference in flow velocity in the cerebral arteries between patients with and without hyperammonemia. Patients with hyperammonemia presented longer ICU stay. Optic nerve sheath thickness was higher in the group with severe hyperammonemia and this group presented an association with intracranial hypertension. Higher mortality was observed in the severe hyperammonemia group. There was an association between severe hyperammonemia and signs of intracranial hypertension. No correlation was found between ammonia levels and cerebral blood flow velocity through the Doppler examination.

• 出版日期2018-8