Cerebral blood flow autoregulation in experimental liver failure

被引:24
作者
Dethloff, Thomas J. [1 ]
Knudsen, Gitte Moos [2 ]
Larsen, Fin Stolze [1 ]
机构
[1] Univ Copenhagen, Rigshosp, Dept Hepatol, DK-2100 Copenhagen O, Denmark
[2] Univ Copenhagen, Rigshosp, Neurobiol Res Unit, Copenhagen O, Denmark
关键词
autoregulatory index; impaired CBF autoregulation; laser Doppler; liver failure; lower limit of autoregulation;
D O I
10.1038/sj.jcbfm.9600589
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Patients with acute liver failure (ALF) display impairment of cerebral blood flow (CBF) autoregulation, which may contribute to the development of fatal intracranial hypertension, but the pathophysiological mechanism remains unclear. In this study, we examined whether loss of liver mass causes impairment of CBF autoregulation. Four rat models were chosen, each representing different aspects of ALF: galactosamine (GIN) intoxication represented liver necrosis, 90% hepatectomy (PHx90) represented reduction in liver mass, portacaval anastomosis (PCA) represented shunting of blood/toxins into the systemic circulation thus mimicking intrahepatic shunting in ALF, PCA+ NH3 provided information about the additional effects of hyperammonemia Rats were intubated and sedated with pentobarbital. We measured CBF with laser Doppler, intracranial pressure (ICP) was measured in the fossa posterior and registered with a pressure transducer, brain water was measured using the wet-to-dry method, and cerebral glutamine/ glutamate was measured enzymatically. The CBF autoregulatory index in both the GIN and PHx90 groups differed significantly from the control group. Conversely, CBF autoregulation was intact in the PCA and PCA+ NH3 groups despite high arterial ammonia, high cerebral glutamine concentration, and increased CBF and ICP. Increased water content of the brainstem or cerebellum was not associated with defective CBF autoregulation. In conclusion, impairment of CBF autoregulation is not caused by brain edema/high ICP. Nor does portacaval shunting or hyperammonemia impair autoregulation. Rather, massive liver necrosis and reduced liver mass are associated with loss of CBF autoregulation.
引用
收藏
页码:916 / 926
页数:11
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