Effect of induced metabolic alkalosis in hepatic encephalopathy

Intracellular pH measurements of the whole head and the basal ganglia in chronic liver disease: a phosphorus-31 MR spectroscopy study

The purpose of this study was to determine the intracellular pH of the whole head and in voxels localized to the basal ganglia in patients with chronic liver disease using phosphorus-31 magnetic resonance spectroscopy (31P MRS). The study group compromised 82 patients with biopsy-proven cirrhosis (43 Child's grade A, 25 Child's grade B and 14 Child's grade C). Eleven subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, 37 showed evidence of minimal hepatic encephalopathy and 34 had overt hepatic encephalopathy. Unlocalized 31P MRS of the whole head was performed in 48 patients and 10 healthy volunteers. Localized 31P MRS of the basal ganglia was performed in the 34 patients and in 20 healthy volunteers. The intracellular pH values were calculated from the chemical shift difference between the inorganic phosphate (P) and phosphocreatine (PCr) resonances. The percentage inorganic phosphate (%Pi), phosphocreatine (%PCr) and betaNTP signals, relative to the total 31P signal, and peak area ratios of inorganic phosphate and phosphocreatine, relative to betaNTP were also measured. There were no differences between patients and volunteers in intracellular pH in 31P MR spectra measured from the whole head or the basal ganglia. There was no correlation between the severity of encephalopathy (West Haven criteria) or liver dysfunction (Child score) and intracellular pH values. There was also no significant change in the inorganic phosphate, phosphocreatine or betaNTP resonances in spectra acquired from the whole head. However, in spectra localized to the basal ganglia, there was a significant increase in mean P/NTP (p=0.02) and PCr/NTP (p=0.009). The mean %Pi and mean %PCr were also increased (p=0.06; p=0.05, respectively), but there was no significant change in mean %betaNTP. When the patient population was classified according to the severity of encephalopathy, those with overt disease had a higher mean P/NTP and %Pi (p=0.03; p=0.01), compared to the reference population. Our results suggest that there are detectable bioenergetic abnormalities in patients with minimal hepatic encephalopathy or stable, overt chronic hepatic encephalopathy, but any associated intracellular pH change is probably a secondary, rather than a primary phenomenon.

Cerebral phosphorus-31 magnetic resonance spectroscopy in patients with chronic hepatic encephalopathy

Cerebral phosphorus-31 magnetic resonance spectroscopy was undertaken in 33 patients with biopsy-proven cirrhosis: 6 had no evidence of neuropsychiatric impairment on standard clinical, psychometric and electrophysiological testing; 8 had evidence of subclinical hepatic encephalopathy; and 19 were classified as having overt hepatic encephalopathy. The reference population comprised 15 healthy volunteers. Unlocalized spectra were acquired from the entire head with a 45-degree pulse angle and repetition times of 1 and 5 sec. Spectra localized to the basal ganglia were acquired with a 45-degree pulse angle and a repetition time of 1 sec. Peak area ratios of phosphomonoesters, inorganic phosphate, phosphodiesters and phosphocreatine relative to beta-ATP were measured in the spectra acquired. We noted no consistent change in the ratios of inorganic phosphate to ATP and phosphocreatine to ATP. Mean values of the ratios of phosphomonoesters to ATP and phosphodiesters to ATP were significantly lower in the total patient population than in the reference population, and they correlated with the patients' neuropsychiatric status. Thus we found no significant reductions in the mean ratios of phosphomonoesters to ATP and phosphodiesters to ATP in patients who were neuropsychiatrically unimpaired, but significant reductions were observed in the mean ratios of phosphomonoesters to ATP and phosphodiesters to ATP in patients with both subclinical and overt hepatic encephalopathy. The most marked reductions in these metabolite ratios were observed in patients with overt encephalopathy.

Cerebral blood flow and plasma free tryptophan in cirrhotics with and without hepatic encephalopathy

Cerebral blood flow (CBF), measured by the non-invasive 133-Xenon inhalation method, plasma levels of ammonia (NH3) and free tryptophan (fTRP) were determined in 30 cirrhotic patients without overt encephalopathy. Psychometric evaluation detected subclinical hepatic encephalopathy (SHE) in 20 of them, and was normal in the other 10. A significant CBF difference (p less than 0.05) was found between the SHE and the non-SHE patients. fTRP levels were significantly (p less than 0.05) higher in patients with SHE than in those without SHE, and a significant negative correlation (p = 0.003) was found between CBF values and fTRP in the whole group of patients. NH3 did not differ in the two subgroups and did not correlate with CBF values. It is concluded that CBF could have some implications in SHE, although its relevance is still unclear. The negative correlation between CBF and fTRP prompts further investigation concerning the relationships between plasma fTRP, brain serotonin, cerebral metabolism and blood flow in the development of brain derangement during cirrhosis.

Cerebral blood flow and liver function in patients with encephalopathy due to acute and chronic liver diseases

The purpose of the present investigation was to study changes in cerebral blood flow (CBF) in hepatic encephalopathy, to ascertain whether this was related to the changes in liver function and whether these changes gave any prognostic information. CBF, determined by the intravenous xenon-133 method, and liver functions, assessed by the prothrombin index, bilirubin concentration, and the galactose elimination capacity, were studied in patients with acute fulminant liver failure and in patients with encephalopathy due to chronic liver diseases--that is, cirrhosis of various etiologies. The CBF range in healthy young subjects (age, 23-42 years) was 44-61 ml/100 g/min; in patients with grade I + II encephalopathy (mean +/- SEM) it was 32.8 +/- 3.6 ml/100 g/min in acute (n = 4; age, 28 +/- 8 years) and 37.0 +/- 3.3 ml/100 g/min in chronic liver patients (n = 10; age, 51 +/- 2 years). In grade III + IV encephalopathy it was 28.7 +/- 3.8 ml/100 g/min in acute (n = 8; age, 28 +/- 3 years) and 32.9 +/- 3.7 ml/100 g/min in chronic patients (n = 12; age, 49 +/- 3 years). CBF did not correlate with the liver function and was of no prognostic value. The liver function was markedly reduced in all the patients, without any differences between patients with acute or chronic liver diseases or the different degrees of hepatic encephalopathy. In conclusion, a marked reduction of the CBF was seen in hepatic encephalopathy, irrespective of the etiology of the disease.

Reduction of cerebral blood flow in subclinical hepatic encephalopathy and its correlation with plasma-free tryptophan

Cerebral blood flow (CBF), measured by the noninvasive xenon-133 inhalation method, EEG, and plasma levels of ammonia (NH3) and free tryptophan were determined in 18 hospitalized cirrhotic patients affected with subclinical hepatic encephalopathy, as diagnosed by the Kurtz test. CBF results were significantly lower (p less than 0.001) in the patients' group as compared with a sex- and age-matched normal control population, although seven patients had values in the normal range. NH3 was increased only in six, while free tryptophan was increased in all but two patients. A significant negative correlation (p = 0.02) between CBF and free tryptophan was found, even though it appears to be difficult to interpret. We suggest that CBF impairment in some cirrhotic patients with subclinical hepatic encephalopathy may be related to the systemic metabolic derangement caused by the liver disease; free tryptophan could have some implication in producing CBF reduction.

Aspectos eletrencefalográficos e da glutaminorraquia nas encefalopatias porto-sistêmicas

Foi estudado um grupo de pacientes com encefalopatia porto-hepática, tendo sido realizada uma análise dos distúrbios da consciência, dos achados eletrencefalográficos e dos níveis liquóricos da glutamina. Baseados nos resultados encontrados, os autores verificaram que o eletrencefalograma pode ser um exame útil na determinação do grau do coma hepático e pode fornecer dados para a avaliação do prognóstico. Concluiram também que a dosagem liquórica da glutamina é o exame mais importante na caracterização do grau de encefalopaita hepática.

Acid-base disturbance in patients with fulminant hepatic failure

Forty-two arterial blood pH and gas determinations were carried out on 11 patients with fulminant hepatic failure. The most common type of acid-base disturbance was that of respiratory alkalosis in 22 cases (52.4%). This was partially compensated in 13 subjects (31.0%) while an accompanying metabolic alkalosis was present in 9 (21.5%). Partially compensated metabolic acidosis was observed on 15 occasions (35.7%), all of which were in patients with laboratory evidence of impaired renal failure. The mental status of the patients was evaluated in each of the categories of acid-base disturbances. Some degree of correlation was evident between the PCO2 and the magnitude of base excess and that of the severity of the encephalopathy. The lower PCO2 and greater negative base excess values tended to be nearly always present in totally comatose subjects. By contrast, there was no clear cut relationship between pH and mental state.

Acute liver failure. Experience in a special unit

Acute liver failure involves disturbances of all major organ systems. The pathophysiology of these disturbances are reviewed and details of management for each system is discussed in clinical work in a special Liver Failure Unit is used to derive principles of treatment, and the use of extracorporeal charcoal haemoperfusion is outlined.

A model which can be used to improve the treatment of acute hepatic failure

A model using the pig from wich the liver has been removed for isolated perfusion, as a subject showing some of the features of acute hepatic failure for later treatment by cross-circulation with its own perfused liver, is desceribed. Effects of such a procedure on such a procedure on the glucose and halothane metabolism and intravascular coagulation and bleeding are detailed.

Extracorporeal perfusion of pig liver in the treatment of acute liver failure

Five patients in deep hepatic coma due to acute liver failure were treated by perfusion of pig liver. All patients showed severe electro-encephalographic changes and 1 patient who recovered showed virtually no cerebral activity. An exchange of 48–94 litres from pig liver to patient was achieved during the procedure. All patients showed neurological improvement after perfusion. Three patients died 2 hours to 10 days after liver perfusion. The remaining 2 patients made a full recovery and are leading a normal life 9 and 14 months after perfusion.