Branched-chain amino acids vs lactulose in the treatment of hepatic coma: a controlled study

ESPEN guideline on clinical nutrition in liver disease

This update of evidence-based guidelines (GL) aims to translate current evidence and expert opinion into recommendations for multidisciplinary teams responsible for the optimal nutritional and metabolic management of adult patients with liver disease. The GL was commissioned and financially supported by ESPEN. Members of the guideline group were selected by ESPEN. We searched for meta-analyses, systematic reviews and single clinical trials based on clinical questions according to the PICO format. The evidence was evaluated and used to develop clinical recommendations implementing the SIGN method. A total of 85 recommendations were made for the nutritional and metabolic management of patients with acute liver failure, severe alcoholic steatohepatitis, non-alcoholic fatty liver disease, liver cirrhosis, liver surgery and transplantation as well as nutrition associated liver injury distinct from fatty liver disease. The recommendations are preceded by statements covering current knowledge of the underlying pathophysiology and pathobiochemistry as well as pertinent methods for the assessment of nutritional status and body composition.

Effect of Hemodiabsorption and Sorbent-Based Pheresis on Amino Acid Levels in Hepatic Failure

Changes in plasma amino acid concentrations were measured in patients with hepatic failure during extracorporeal hemodiabsorption (using the Liver Dialysis Unit, “the Unit”) or hemodiabsorption plus sorbent-based pheresis treatment (using the Liver Dialysis Plasmafilter Unit, “the PF-Unit”) Systems.

Eight patients with hepatic failure, grade 3 or 4 encephalopathy, elevated bilirubin and/or creatinine levels and respiratory or renal failure were treated for 1–3 days with the Unit alone. Three of these were also treated with the Unit containing 10 g of BCAA in the sorbent suspension. Four patients with hepatic failure treated with the PF Unit also had 10 g of branched chain amino acid (BCAA) added to the sorbents of the Unit portion of this device. Pre- and post-plasma samples were drawn and high performance liquid chromatography (HPLC) was used to separate and detect amino acids in the plasma.

Both the Unit and the PF-Unit have the capability to selectively remove various amino acids, especially aromatic amino acids (AAA). The pre-treatment amino acid profiles of plasma were typical for hepatic failure, with abnormally high levels of phenylalanine, tyrosine, tryptophan, and methionine and decreased levels of valine, leucine and isolucine.

The average pre-treatment Fischer ratio (BCAA/AAA) for both Unit and PF-Unit patients was 1.43 (±0.58). Treatments by both systems resulted in an increase of BCAA levels in blood and concomitant decrease of AAA levels, with an average Fischer ratio improvement of 30–38% for the Unit and PF-Unit without BCAA. The Fischer ratio improved by 90% (average) for the Unit with BCAA. Levels of many other amino acids (such as alanine, glycine, proline or lysine) increased during both Unit and PF-Unit treatments. The removal of strongly protein-bound toxin and amino acids such as tryptophan and sulphydryl amino acids was more effective by the PF-Unit.

Both the Unit and the PF-Unit have the unique capability to remove toxic aromatic amino acids while increasing BCAA levels in patient. The increase in many amino acid levels may be related to the removal of toxins that interfere with normal amino acid metabolism. The addition of the PF module improves the removal of bilirubin and similarly protein-bound chemicals. Changes in amino acid profiles by the Unit and the PF-Unit contrast markedly with other extracorporeal devices.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded and Conference Proceedings Citation Index - Science, and LILACS (May 2017).

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. We classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index (August 2015).

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. We classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Branched-chain amino acids for people with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy is a brain dysfunction with neurological and psychiatric changes associated with liver insufficiency or portal-systemic shunting. The severity ranges from minor symptoms to coma. A Cochrane systematic review including 11 randomised clinical trials on branched-chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy.

SEARCH METHODS

We identified trials through manual and electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index on 2 October 2014.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of the bias control, language, or publication status.

DATA COLLECTION AND ANALYSIS

The authors independently extracted data based on published reports and collected data from the primary investigators. We changed our primary outcomes in this update of the review to include mortality (all cause), hepatic encephalopathy (number of people without improved manifestations of hepatic encephalopathy), and adverse events. The analyses included random-effects and fixed-effect meta-analyses. We performed subgroup, sensitivity, regression, and trial sequential analyses to evaluate sources of heterogeneity (including intervention, and participant and trial characteristics), bias (using The Cochrane Hepato-Biliary Group method), small-study effects, and the robustness of the results after adjusting for sparse data and multiplicity. We graded the quality of the evidence using the GRADE approach.

MAIN RESULTS

We found 16 randomised clinical trials including 827 participants with hepatic encephalopathy classed as overt (12 trials) or minimal (four trials). Eight trials assessed oral BCAA supplements and seven trials assessed intravenous BCAA. The control groups received placebo/no intervention (two trials), diets (10 trials), lactulose (two trials), or neomycin (two trials). In 15 trials, all participants had cirrhosis. Based on the combined Cochrane Hepato-Biliary Group score, we classed seven trials as low risk of bias and nine trials as high risk of bias (mainly due to lack of blinding or for-profit funding). In a random-effects meta-analysis of mortality, we found no difference between BCAA and controls (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.69 to 1.11; 760 participants; 15 trials; moderate quality of evidence). We found no evidence of small-study effects. Sensitivity analyses of trials with a low risk of bias found no beneficial or detrimental effect of BCAA on mortality. Trial sequential analysis showed that the required information size was not reached, suggesting that additional evidence was needed. BCAA had a beneficial effect on hepatic encephalopathy (RR 0.73, 95% CI 0.61 to 0.88; 827 participants; 16 trials; high quality of evidence). We found no small-study effects and confirmed the beneficial effect of BCAA in a sensitivity analysis that only included trials with a low risk of bias (RR 0.71, 95% CI 0.52 to 0.96). The trial sequential analysis showed that firm evidence was reached. In a fixed-effect meta-analysis, we found that BCAA increased the risk of nausea and vomiting (RR 5.56; 2.93 to 10.55; moderate quality of evidence). We found no beneficial or detrimental effects of BCAA on nausea or vomiting in a random-effects meta-analysis or on quality of life or nutritional parameters. We did not identify predictors of the intervention effect in the subgroup, sensitivity, or meta-regression analyses. In sensitivity analyses that excluded trials with a lactulose or neomycin control, BCAA had a beneficial effect on hepatic encephalopathy (RR 0.76, 95% CI 0.63 to 0.92). Additional sensitivity analyses found no difference between BCAA and lactulose or neomycin (RR 0.66, 95% CI 0.34 to 1.30).

AUTHORS' CONCLUSIONS

In this updated review, we included five additional trials. The analyses showed that BCAA had a beneficial effect on hepatic encephalopathy. We found no effect on mortality, quality of life, or nutritional parameters, but we need additional trials to evaluate these outcomes. Likewise, we need additional randomised clinical trials to determine the effect of BCAA compared with interventions such as non-absorbable disaccharides, rifaximin, or other antibiotics.

Nutritional support for liver disease

BACKGROUND

Weight loss and muscle wasting are commonly found in patients with end-stage liver disease. Since there is an association between malnutrition and poor clinical outcome, such patients (or those at risk of becoming malnourished) are often given parenteral nutrition, enteral nutrition, or oral nutritional supplements. These interventions have costs and adverse effects, so it is important to prove that their use results in improved morbidity or mortality, or both.

OBJECTIVES

To assess the beneficial and harmful effects of parenteral nutrition, enteral nutrition, and oral nutritional supplements on the mortality and morbidity of patients with underlying liver disease.

SEARCH METHODS

The following computerised databases were searched: the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, and Science Citation Index Expanded (January 2012). In addition, reference lists of identified trials and review articles and Clinicaltrials.gov were searched. Trials identified in a previous systematic handsearch of Index Medicus were also considered. Handsearches of a number of medical journals, including abstracts from annual meetings, were done. Experts in the field and manufacturers of nutrient formulations were contacted for potential references.

SELECTION CRITERIA

Randomised clinical trials (parallel or cross-over design) comparing groups of patients with any underlying liver disease who received, or did not receive, enteral or parenteral nutrition or oral nutritional supplements were identified without restriction on date, language, or publication status. Six categories of trials were separately considered: medical or surgical patients receiving parenteral nutrition, enteral nutrition, or supplements.

DATA COLLECTION AND ANALYSIS

The following data were sought in each report: date of publication; geographical location; inclusion and exclusion criteria; the type of nutritional support and constitution of the nutrient formulation; duration of treatment; any nutrition provided to the controls; other interventions provided to the patients; number, sex, age of the study participants; hospital or outpatient status; underlying liver disease; risks of bias (sequence generation, allocation concealment, blinding, incomplete outcome reporting, intention-to-treat analysis, selective outcome reporting, others (vested interests, baseline imbalance, early stopping)); mortality; hepatic morbidity (development or resolution of ascites or hepatic encephalopathy, occurrence of gastrointestinal bleeding); quality of life scores; adverse events; infections; lengths of stay in the hospital or intensive care unit; costs; serum bilirubin; postoperative complications (surgical trials only); and nutritional outcomes (nitrogen balance, anthropometric measurements, body weight). The primary outcomes of this review were mortality, hepatic morbidity, quality of life, and adverse events. Data were extracted in duplicate; differences were resolved by consensus.Data for each outcome were combined in a meta-analysis (RevMan 5.1). Estimates were reported using risk ratios or mean differences, along with the 95% confidence intervals (CI). Both fixed-effect and random-effects models were employed; fixed-effect models were reported unless one model, but not the other, found a significant difference (in which case both were reported). Heterogeneity was assessed by the Chi(2) test and I(2) statistic. Subgroup analyses were planned to assess specific liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma), acute or chronic liver diseases, and trials employing standard or branched-chain amino acid formulations (for the hepatic encephalopathy outcomes). Sensitivity analyses were planned to compare trials at low and high risk of bias and trials reported as full papers. The following exploratory analyses were undertaken: 1) medical and surgical trials were combined for each nutritional intervention; 2) intention-to-treat analyses in which missing dichotomous data were imputed as best- and worst-case scenarios; 3) all trials were combined to assess mortality; 4) effects were estimated by absolute risk reductions.

MAIN RESULTS

Thirty-seven trials were identified; only one was at low risk of bias. Most of the analyses failed to find any significant differences. The significant findings that were found were the following: 1) icteric medical patients receiving parenteral nutrition had a reduced serum bilirubin (mean difference (MD) -2.86 mg%, 95% CI -3.82 mg% to -1.89 mg%, 3 trials) and better nitrogen balance (MD 3.60 g/day, 95% CI 0.86 g/day to 6.34 g/day, 1 trial); 2) surgical patients receiving parenteral nutrition had a reduced incidence of postoperative ascites only in the fixed-effect model (RR 0.65, 95% CI 0.48 to 0.87, 2 trials, I(2) = 70%) and one trial demonstrated a reduction in postoperative complications, especially infections (pneumonia in particular); 3) enteral nutrition may have improved nitrogen balance in medical patients (although a combination of the three trials was not possible); 4) one surgical trial of enteral nutrition found a reduction in postoperative complications; and 5) oral nutritional supplements had several effects in medical patients (reduced occurrence of ascites (RR 0.57, 95% CI 0.37 to 0.88, 3 trials), possibly (significant differences only seen in the fixed-effect model) reduced rates of infection (RR 0.49, 95% CI 0.24 to 0.99, 3 trials, I(2) = 14%), and improved resolution of hepatic encephalopathy (RR 3.75, 95% CI 1.15 to 12.18, 2 trials, I(2) = 79%). While there was no overall effect of the supplements on mortality in medical patients, the one low risk of bias trial found an increased risk of death in the recipients of the supplements. Three trials of supplements in surgical patients failed to show any significant differences. No new information was derived from the various subgroup or sensitivity analyses. The exploratory analyses were also unrevealing except for a logical conundrum. There was no difference in mortality when all of the trials were combined, but the trials of parenteral nutrition found that those recipients had better survival (RR 0.53, 95% CI 0.29 to 0.98, 10 trials). Either the former observation represents a type II error or the latter one a type I error.

AUTHORS' CONCLUSIONS

The data do not compellingly justify the routine use of parenteral nutrition, enteral nutrition, or oral nutritional supplements in patients with liver disease. The fact that all but one of these trials were at high risks of bias even casts doubt on the few benefits that were demonstrated. Data from well-designed and executed randomised trials that include an untreated control group are needed before any such recommendation can be made. Future trials have to be powered adequately to see small, but clinically important, differences.

Nutritional support for liver disease

BACKGROUND

Weight loss and muscle wasting are commonly found in patients with end-stage liver disease. Since there is an association between malnutrition and poor clinical outcome, such patients (or those at risk of becoming malnourished) are often given parenteral nutrition, enteral nutrition, or oral nutritional supplements. These interventions have costs and adverse effects, so it is important to prove that their use results in improved morbidity or mortality, or both.

OBJECTIVES

To assess the beneficial and harmful effects of parenteral nutrition, enteral nutrition, and oral nutritional supplements on the mortality and morbidity of patients with underlying liver disease.

SEARCH METHODS

The following computerised databases were searched: the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, and Science Citation Index Expanded (January 2012). In addition, reference lists of identified trials and review articles and Clinicaltrials.gov were searched. Trials identified in a previous systematic handsearch of Index Medicus were also considered. Handsearches of a number of medical journals, including abstracts from annual meetings, were done. Experts in the field and manufacturers of nutrient formulations were contacted for potential references.

SELECTION CRITERIA

Randomised clinical trials (parallel or cross-over design) comparing groups of patients with any underlying liver disease who received, or did not receive, enteral or parenteral nutrition or oral nutritional supplements were identified without restriction on date, language, or publication status. Six categories of trials were separately considered: medical or surgical patients receiving parenteral nutrition, enteral nutrition, or supplements.

DATA COLLECTION AND ANALYSIS

The following data were sought in each report: date of publication; geographical location; inclusion and exclusion criteria; the type of nutritional support and constitution of the nutrient formulation; duration of treatment; any nutrition provided to the controls; other interventions provided to the patients; number, sex, age of the study participants; hospital or outpatient status; underlying liver disease; risks of bias (sequence generation, allocation concealment, blinding, incomplete outcome reporting, intention-to-treat analysis, selective outcome reporting, others (vested interests, baseline imbalance, early stopping)); mortality; hepatic morbidity (development or resolution of ascites or hepatic encephalopathy, occurrence of gastrointestinal bleeding); quality of life scores; adverse events; infections; lengths of stay in the hospital or intensive care unit; costs; serum bilirubin; postoperative complications (surgical trials only); and nutritional outcomes (nitrogen balance, anthropometric measurements, body weight). The primary outcomes of this review were mortality, hepatic morbidity, quality of life, and adverse events. Data were extracted in duplicate; differences were resolved by consensus.Data for each outcome were combined in a meta-analysis (RevMan 5.1). Estimates were reported using risk ratios or mean differences, along with the 95% confidence intervals (CI). Both fixed-effect and random-effects models were employed; fixed-effect models were reported unless one model, but not the other, found a significant difference (in which case both were reported). Heterogeneity was assessed by the Chi(2) test and I(2) statistic. Subgroup analyses were planned to assess specific liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma), acute or chronic liver diseases, and trials employing standard or branched-chain amino acid formulations (for the hepatic encephalopathy outcomes). Sensitivity analyses were planned to compare trials at low and high risk of bias and trials reported as full papers. The following exploratory analyses were undertaken: 1) medical and surgical trials were combined for each nutritional intervention; 2) intention-to-treat analyses in which missing dichotomous data were imputed as best- and worst-case scenarios; 3) all trials were combined to assess mortality; 4) effects were estimated by absolute risk reductions.

MAIN RESULTS

Thirty-seven trials were identified; only one was at low risk of bias. Most of the analyses failed to find any significant differences. The significant findings that were found were the following: 1) icteric medical patients receiving parenteral nutrition had a reduced serum bilirubin (mean difference (MD) -2.86 mg%, 95% CI -3.82 mg% to -1.89 mg%, 3 trials) and better nitrogen balance (MD 3.60 g/day, 95% CI 0.86 g/day to 6.34 g/day, 1 trial); 2) surgical patients receiving parenteral nutrition had a reduced incidence of postoperative ascites only in the fixed-effect model (RR 0.65, 95% CI 0.48 to 0.87, 2 trials, I(2) = 70%) and one trial demonstrated a reduction in postoperative complications, especially infections (pneumonia in particular); 3) enteral nutrition may have improved nitrogen balance in medical patients (although a combination of the three trials was not possible); 4) one surgical trial of enteral nutrition found a reduction in postoperative complications; and 5) oral nutritional supplements had several effects in medical patients (reduced occurrence of ascites (RR 0.57, 95% CI 0.37 to 0.88, 3 trials), possibly (significant differences only seen in the fixed-effect model) reduced rates of infection (RR 0.49, 95% CI 0.24 to 0.99, 3 trials, I(2) = 14%), and improved resolution of hepatic encephalopathy (RR 3.75, 95% CI 1.15 to 12.18, 2 trials, I(2) = 79%). While there was no overall effect of the supplements on mortality in medical patients, the one low risk of bias trial found an increased risk of death in the recipients of the supplements. Three trials of supplements in surgical patients failed to show any significant differences. No new information was derived from the various subgroup or sensitivity analyses. The exploratory analyses were also unrevealing except for a logical conundrum. There was no difference in mortality when all of the trials were combined, but the trials of parenteral nutrition found that those recipients had better survival (RR 0.53, 95% CI 0.29 to 0.98, 10 trials). Either the former observation represents a type II error or the latter one a type I error.

AUTHORS' CONCLUSIONS

The data do not compellingly justify the routine use of parenteral nutrition, enteral nutrition, or oral nutritional supplements in patients with liver disease. The fact that all but one of these trials were at high risks of bias even casts doubt on the few benefits that were demonstrated. Data from well-designed and executed randomised trials that include an untreated control group are needed before any such recommendation can be made. Future trials have to be powered adequately to see small, but clinically important, differences.

Hepatology - Guidelines on Parenteral Nutrition, Chapter 16

Parenteral nutrition (PN) is indicated in alcoholic steatohepatitis (ASH) and in cirrhotic patients with moderate or severe malnutrition. PN should be started immediately when sufficientl oral or enteral feeding is not possible. ASH and cirrhosis patients who can be sufficiently fed either orally or enterally, but who have to abstain from food over a period of more than 12 hours (including nocturnal fasting) should receive basal glucose infusion (2–3 g/kg/d). Total PN is required if such fasting periods last longer than 72 h. PN in patients with higher-grade hepatic encephalopathy (HE); particularly in HE IV° with malfunction of swallowing and cough reflexes, and unprotected airways. Cirrhotic patients or patients after liver transplantation should receive early postoperative PN after surgery if they cannot be sufficiently rally or enterally nourished. No recommendation can be made on donor or organ conditioning by parenteral administration of glutamine and arginine, aiming at minimising ischemia/reperfusion damage. In acute liver failure artificial nutrition should be considered irrespective of the nutritional state and should be commenced when oral nutrition cannot be restarted within 5 to 7 days. Whenever feasible, enteral nutrition should be administered via a nasoduodenal feeding tube.

ESPEN Guidelines on Parenteral Nutrition: hepatology

Parenteral nutrition (PN) offers the possibility to increase or to ensure nutrient intake in patients, in whom sufficient nutrition by oral or enteral alone is insufficient or impossible. Complementary to the ESPEN guideline on enteral nutrition of liver disease (LD) patients the present guideline is intended to give evidence-based recommendations for the use of PN in LD. For this purpose three paradigm conditions of LD were chosen: alcoholic steatohepatitis (ASH), liver cirrhosis and acute liver failure. The guideline was developed by an interdisciplinary expert group in accordance with officially accepted standards and is based on all relevant publications since 1985. The guideline was presented on the ESPEN website and visitors' criticism and suggestions were welcome and included in the final revision. PN improves nutritional state and liver function in malnourished patients with ASH. PN is safe and improves mental state in patients with cirrhosis and severe HE. Perioperative (including liver transplantation) PN is safe and reduces the rate of complications. In acute liver failure PN is a safe second-line option to adequately feed patients in whom enteral nutrition is insufficient or impossible.

Role of branched-chain amino acids in management of cirrhosis and hepatocellular carcinoma

Altered protein and energy metabolism is a hallmark of chronic liver disease, characterized by decreased plasma branched-chain amino acids (BCAA) and increased plasma aromatic amino acids (AAA). Overwhelming evidence has indicated that the incidence of complications of chronic liver disease increases with malnutrition. Hence nutritional management in patients with chronic liver disease must receive high priority. The use of BCAA supplementation has been a controversial subject. This review summarizes published results of BCAA supplementation as a nutritional therapy for patients with cirrhosis and hepatocellular carcinoma (HCC). On balance, it would be appropriate to conclude that BCAA are associated with decreased frequency of complications of cirrhosis and improved nutritional status when prescribed as a maintenance therapy for patients with cirrhosis. More studies are, however, required to identify those who might benefit most from BCAA supplementation.

High lipid parenteral feeds raise plasma branched chain amino acid concentrations--a possible therapeutic approach to portasystemic encephalopathy?

The effect of varying the calorie source of parenteral feeding from an all glucose source to a high fat source has been studied in seven patients with normal liver function by randomised crossover trial. 'Intralipid' used as the major non-nitrogen calorie source (except for 400 kcal as glucose) was associated with significantly lower plasma concentrations of insulin and glucose, significantly higher plasma concentrations of the three branched chain amino acids, and a significantly higher urinary excretion of sodium. If these effects of a high fat parenteral feed were repeatable in patients with liver failure and portasystemic encephalopathy they might be of therapeutic benefit.

The role of nutrition in hepatic encephalopathy

PURPOSE OF REVIEW

Protein-calorie malnutrition may be observed in all clinical stages of liver disease. Nutritional management in these patients is imperative. It is crucial that protein intake is not restricted ad hoc. Administration of vegetable proteins for patients who cannot tolerate standard proteins and, if necessary, branched-chain amino acid-enriched formulae can be an option to these patients. This issue, however, remains controversial.

RECENT FINDINGS

This study is an update on the nutritional management of hepatic encephalopathy based on several studies of the last decades, involving dietary protein intake and branched-chain amino acid supplementation.

SUMMARY

Malnutrition is a common complication of liver disease and it adversely affects patient outcome. Inadequate dietary protein intake has a very deleterious effect on hepatic encephalopathy, nutritional status, and clinical outcome in these patients and must be avoided. The administration of branched-chain amino acids stimulates hepatic protein synthesis, reduces postinjury catabolism and therefore improves nutritional status. Conflicting results in various different trials, however, exist, and this issue remains unclear.

Do Data Support Nutrition Support? Part I: Intravenous Nutrition

Intravenous (parenteral) nutrition has been advocated widely as adjunctive care in patients with a variety of underlying diseases. However, the enthusiasm for this therapeutic intervention was based largely on expert opinion. Because the best way to assess the efficacy of any treatment is to test it in a randomized controlled trial, this review will focus on data that was derived from such studies. Using established search strategies, randomized controlled trials were sought that compared one of two forms of intravenous nutrition: parenteral nutrition (nitrogen and >or=10 kcal/kg/day of non-protein calories for >or=5 days) or protein-sparing therapy (nitrogen and fewer non-protein calories) with no type of artificial nutrition beyond regular food and/or standard (5%) dextrose. The randomized controlled trials were stratified by the underlying disease state. The clinical outcomes of interest were mortality, morbidity (total/infectious complications), and/or duration of hospitalization. More than 100 randomized controlled trials failed for the most part to demonstrate that intravenous nutrition had any effect on clinical outcome. There were a few exceptions. In patients undergoing attempted curative surgery for upper gastrointestinal cancer, the use of preoperative parenteral nutrition seemed to reduce the incidence of major postoperative complications. However, this benefit was only found in low-quality randomized controlled trials. Findings conflict regarding the use of parenteral nutrition in patients with acute pancreatitis or undergoing bone marrow transplantation. Parenteral nutrition was harmful when provided to patients undergoing radiation or chemotherapy for cancer. Although no randomized controlled trials exist, it is assumed that parenteral nutrition is useful in patients with an inadequate gastrointestinal tract ("short gut"). Thus, for the most part, randomized controlled trials comparing intravenous nutrition to no artificial nutrition have not shown that this medical intervention is of benefit.

Role of branched-chain amino acids in liver disease: the evidence for and against

PURPOSE OF REVIEW

There is ample evidence that patients with liver disease have an ongoing energy and protein catabolism. Nutritional management in these patients must receive high priority. The administration of branched-chain amino acids to patients with liver disease has been a controversial subject. This review is an update on the data available from various studies involving branched-chain amino acids supplementation in patients with chronic liver disease and associated complications.

RECENT FINDINGS

This review summarizes the results of nutritional interventions involving branched-chain amino acids supplementation carried out in different centres around the world. It is interesting to note that no toxic effects of branched-chain amino acids supplementation have been reported in any of these trials.

SUMMARY

Administration of branched-chain amino acids stimulates hepatic protein synthesis in patients with chronic liver disease and this could contribute significantly to improving their nutritional status, and result in a better quality of life. The beneficial role of branched-chain amino acids supplementation in patients with chronic hepatic encephalopathy has been clearly documented in some studies but the exact mechanism of action is still not clear.

Formal heparin anticoagulation protocol improves safety of charcoal-based liver-assist treatments

Extracorporeal devices have had limited effectiveness in liver failure due to consequences of inadequate anticoagulation. The purpose of this study was to evaluate an anticoagulation protocol developed for Liver Dialysis Unit (LDU) treatments. Twelve patients underwent 19 LDU treatments for acetaminophen overdose (n = 1), subacute liver failure (n = 1), and refractory encephalopathy in cirrhosis (n = 10). The initial 6 patients (group 1) were treated according to the manufacturer's recommendations. The subsequent 6 patients (group 2) were treated using a formal heparin anticoagulation protocol that included 2000 units in prime solution and 30 units/kg induction, activated clotting time (ACT) measurements, and heparin administered by dose-response curve to maintain 300-second ACT. Protamine reversal was used. Treatments were well tolerated and equally effective in both groups. Adequate (ACT > or = 250 seconds) and therapeutic (ACT 250-350 seconds) anticoagulation was maintained more consistently in group 2 (90.9% vs 50.0%, p < 0.0001; and 77.4% vs 45.8%, p < 0.001). There was less consumption of fibrinogen (12.1% vs 43.3%, p < 0.005) and platelets (13.8% vs 29.9%, p < 0.05) and a trend for less blood product used (8.3 vs 15.8 units/patient, p = 0.13) and fewer complications (16.7% vs 66.7%, p = 0.15) in group 2. Anticoagulation using ACT monitoring, heparin dose-response curves, and a target ACT of 300 seconds improves the safety of LDU treatments.

Branched-chain amino acids: the best compromise to achieve anabolism?

PURPOSE OF REVIEW

The anorexia-cachexia syndrome is highly prevalent in patients suffering from acute and chronic diseases, including cancer, chronic renal failure and liver cirrhosis. Once it has developed, it significantly influences the clinical course of the underlying disease, simultaneously impinging on patients' quality of life. Unfortunately, currently available therapeutic strategies do not appear to greatly impact on patients' morbidity, mortality and quality of life. More effective therapies are needed to promote appetite and food intake, to preserve lean body mass, and to ameliorate patients' psychological distress.

RECENT FINDINGS

Branched-chain amino acids are neutral amino acids with interesting and clinically relevant metabolic effects. Their potential role as antianorexia and anticachexia agents was proposed many years ago, but only recent experimental studies and clinical trials have tested their ability to stimulate food intake and counteract muscle wasting in anorectic, weight-losing patients. By interfering with brain serotonergic activity and by inhibiting the overexpression of critical muscular proteolytic pathways, branched-chain amino acids have been shown to induce beneficial metabolic and clinical effects under different pathological conditions.

SUMMARY

Based on the available data, branched-chain amino acids appear to exert significant antianorectic and anticachectic effects, and their supplementation may represent a viable intervention not only for patients suffering from chronic diseases, but also for those individuals at risk of sarcopenia due to age, immobility or prolonged bed rest, including trauma, orthopedic or neurologic patients.

Branched-chain amino acid supplementation in patients with liver diseases

Because of their peculiar role in whole-body nitrogen metabolism and the competitive action on amino acid transport across the blood-brain barrier, branched-chain amino acids (BCAAs) have been extensively used in subjects with liver disease to preserve or to restore muscle mass and to improve hepatic encephalopathy. There are no data regarding safe limits of BCAA administration; the results appear to be better when BCAA-enriched formulas or BCAA-supplemented diets are preferred to pure BCAA formulas. Improved nitrogen retention might ameliorate the nutritional status, a prognostic index of long-term survival in cirrhosis and of short-term survival in patients undergoing surgical procedures. The effects on nutrition and ultimately on prognosis of patients with advanced cirrhosis were confirmed in a large multicenter, long-term trial where oral BCAA supplements were compared with equicaloric or equinitrogenous-equicaloric supplements (maltodextrin or lactoalbumin). Similarly, BCAA treatment improved the prognosis of patients with hepatocellular carcinoma, treated by surgical resection or chemoembolization, and of liver transplant patients. The mechanism(s) for the beneficial effects of BCAAs might be mediated by their stimulating activity on hepatocyte growth factor, favoring liver regeneration. The debate regarding the potential effectiveness of BCAAs dates back to the early 1980s. The number of patients who cannot tolerate dietary proteins in amounts sufficient to meet the higher catabolism of advanced liver disease is probably low, but BCAAs remain the sole treatment of proved efficacy in this specific setting.

New support for branched-chain amino acid supplementation in advanced hepatic failure

Nutritional supplementation with branched-chain amino acids (BCAA) has been a topic of considerable debate for more than two decades. Several studies have demonstrated that supplementation with BCAA is associated with improvement of the catabolic state commonly seen in people with cirrhosis, whereas other studies have showed an improvement in portosystemic encephalopathy in patients with liver disease. Some studies have also shown there to be no benefit in BCAA supplementation in advanced cirrhosis. A recent large clinical trial showed that long-term BCAA supplementation may be useful in preventing progressive hepatic failure and improving liver function in some patients.

Nonabsorbable disaccharides for hepatic encephalopathy

BACKGROUND

Nonabsorbable disaccharides (lactulose or lactitol) are considered the treatment of choice for hepatic encephalopathy.

OBJECTIVES

To assess the beneficial and harmful effects of nonabsorbable disaccharides for patients with hepatic encephalopathy.

SEARCH STRATEGY

Trials were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register (March 2003), The Cochrane Central Register of Controlled Trials (Issue 1, 2003), MEDLINE (1966 to 2003/03), EMBASE (1980 to 2003/03), manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing lactulose or lactitol versus no intervention, placebo, or antibiotics and trials comparing lactulose versus lactitol for hepatic encephalopathy.

DATA COLLECTION AND ANALYSIS

The primary outcome measures included no improvement of hepatic encephalopathy and all-cause mortality. Binary outcomes are reported as relative risks (RR) based on a random effects model. Subgroup analyses were performed with regard to methodological quality and form of hepatic encephalopathy.

MAIN RESULTS

Thirty trials assessed nonabsorbable disaccharides versus placebo, no intervention, or antibiotics or assessed lactulose versus lactitol. We could not extract data from all trials. Compared with placebo or no intervention, nonabsorbable disaccharides had no statistically significant effect on mortality (RR 0.41, 95% CI 0.02 to 8.68, four trials), but appeared to reduce the risk of no improvement of hepatic encephalopathy (RR 0.62, 95% CI 0.46 to 0.84, six trials). However, this result may reflect bias due to low methodological quality of the majority of included trials. Trials of high methodological quality found no significant effect of nonabsorbable disaccharides on the risk of no improvement (RR 0.92, 95% CI 0.42 to 2.04, two trials). We found no statistically significant difference between lactulose and lactitol on mortality (two trials) or risk of no improvement (four trials). However, our meta-analyses were underpowered to establish whether these treatments have comparable effect. Nonabsorbable disaccharides appeared to be inferior to antibiotics on reducing the risk of no improvement (RR 1.24, 95% CI 1.02 to 1.50, 10 trials).

REVIEWERS' CONCLUSIONS

This systematic review questions the beneficial effects of nonabsorbable disaccharides and highlights that there is insufficient high-quality evidence to support this treatment. We found that antibiotics appeared to be superior to nonabsorbable disaccharides in improving hepatic encephalopathy, but it is unclear whether this difference in treatment effect is clinically important to patients. Nonabsorbable disaccharides should not serve as comparator in randomised trials on hepatic encephalopathy.

Charcoal-based hemodiabsorption liver support for episodic type C hepatic encephalopathy

OBJECTIVES

Episodic (acute) type C hepatic encephalopathy (AHE) fails to respond to 5 days of medical therapy in 10-30% of patients and carries a 10-30% mortality rate. We prospectively studied extracorporeal liver support for AHE failing to respond to medical therapy to assess its safety and efficacy and the role of anticoagulation.

METHODS

A series of patients with cirrhosis and AHE failing to respond to at least 24 h of medical therapy underwent a maximum of three 6-h charcoal-based hemodiabsorption (Liver Dialysis Unit) treatments. A standard anticoagulation protocol, with heparin dosing based on activated clotting time (ACT) determinations, heparin dose-response curve, and target ACT of 275-300 s, was developed. Therapy was terminated if patients met a predetermined clinical response, deteriorated, or underwent transplantation.

RESULTS

Eighteen patients with grade 2-4 AHE despite 5.9 +/- 3.9 days of medical therapy underwent a mean of 1.6 treatments. In 2.6 +/- 1.9 days, 16 patients (88.9%) improved to less than grade 2 HE or achieved at least a 50% hepatic encephalopathy index (HEI) reduction. Median mental status (grade 2 vs 1, p < 0.05) and HEI (0.634 +/- 0.194 vs 0.363 +/- 0.263, p < 0.005) improved significantly. Survival was 94.4% and 72.2% at 5 and 30 days, respectively. Use of our developed anticoagulation protocol resulted in less platelet (14.2% +/- 2.8% vs 32.5% +/- 5.8%, p < 0.005) and fibrinogen consumption (12.1% +/- 3.5% vs 43.3% +/- 8.6%, p < 0.0005) and blood product use (6.2 +/- 1.8 vs 19.0 +/- 5.6 units, p < 0.05) compared with treatments according to manufacturer's guidelines.

CONCLUSIONS

Charcoal-based hemodiabsorption treatments in which a standardized anticoagulation protocol is used is safe and effective treatment for AHE not responding to standard medical therapy.

Branched-chain amino acids for hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of BCAA for patients with hepatic encephalopathy.

SEARCH STRATEGY

We identified trials through The Cochrane Hepato-Biliary Group Controlled Trials Register (September 2002), (Issue 3, 2002), MEDLINE (1966-2002/09) and EMBASE (1980-2002/05), manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing BCAA with any kind of control therapy for hepatic encephalopathy were included, regardless of blinding, language, or publication status.

DATA COLLECTION AND ANALYSIS

Trial inclusion and data extraction were made independently by two reviewers. Our primary outcome was improvement of hepatic encephalopathy. Statistical heterogeneity was tested using random effects and fixed effect models. Binary outcomes are reported as risk ratios (RR) based on a random effects model.

MAIN RESULTS

Eleven randomised trials (556 patients) assessing BCAA versus carbohydrates, neomycin/lactulose, or isonitrogenous control were included. The median number of patients in each trial was 55 (range 22 to 75). Follow-up after treatment was reported in four trials (median 17 days (range 6 to 30 days)). Compared to the control regimens, BCAA significantly increased the number of patients improving from hepatic encephalopathy at the end of treatment (risk ratio (RR) 1.31, 95% confidence interval (CI) 1.04 to 1.66, nine trials). We found no evidence of an effect of BCAA on survival (RR 1.06, 95% CI 0.98 to 1.14, eight trials) or adverse events (RR 0.97, 95% CI 0.41 to 2.31, three trials). Sensitivity analyses indicated that methodological quality had significant impact on the results. We found no evidence of an effect of BCAA on improvement of hepatic encephalopathy in trials with adequate generation of the allocation sequence (RR 1.01, 95% CI 0.84 to 1.23, three trials), adequate allocation concealment (RR 1.09, 95% CI 0.89 to 1.33, five trials), or adequate double-blinding (RR 1.20, 95% CI 0.83 to 1.73, three trials).

REVIEWER'S CONCLUSIONS

We did not find convincing evidence that BCAA had a significant beneficial effect on patients with hepatic encephalopathy. The trials performed in this field were small with short follow-up and most had low methodological quality.

AGA technical review on parenteral nutrition

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the Committee on September 13, 2001, and by the AGA Governing Board on May 18, 2001.

New aspects on etiology, biochemistry, and therapy of portal systemic encephalopathy: a critical survey

There is scientific agreement that portal systemic encephalopathy (PSE) is caused morphologically by portal systemic shunts and biochemically by constituents of the portal venous blood. Ammonium has a key role in the pathogenesis of PSE. Direct correlations with the degree of PSE have been established exclusively with glutamine, i.e. the terminal product of the peripheral detoxification of ammonium. In PSE, ammonium is probably responsible for damage to astrocytic and neuronal cells. Ammonium's toxic effect is due to the intracerebral glutamine synthesis. After several metabolic steps, which will be discussed in detail, brain cell damage is caused directly or indirectly (exitotoxically) by energy deficiency. Hyperammonemia and PSE are each well defined though different forms of disturbance. Therefore, ammonium is not the sole decisive factor in the pathogenesis of PSE. We performed a detailed and critical analysis of all studies on amino acid therapy of PSE, especially those that were randomized and controlled. This analysis revealed a close and direct correlation between qualitative and quantitative dosages of amino acids on one hand, and parallel improvements of amino acid imbalance (essentially associated with PSE) and degree of PSE on the other. A close and direct dose/efficacy correlation must be assumed. Disturbed plasmatic amino acid homeostasis and cerebral monoaminergic neurotransmission are probably important pathogenic factors of PSE. A fundamental cofactor in the efficacy of each adequate amino acid therapy might be a substantial decrease of endogenous ammonium production. Physiologic benzodiazepines may also have an important function in the pathogenesis of PSE: not so, however, the glutamate-ergic and GABA-ergic neurotransmission, which are disturbed principally in PSE. In close correlation to pathogenesis, established and proposed therapies of PSE are critically discussed.

Clinical economics review: nutritional support

Nutritional support currently accounts for about 1% of the total health care costs in the USA. Interestingly, most of the prospective randomized controlled trials to date have not been able to demonstrate that this therapeutic intervention alters morbidity or mortality. In fact, parenteral nutritional support may predispose the recipients to developing systemic infections. There have been a few areas in which nutritional support may be of benefit. Enteral supplements given to underweight women who suffer hip fractures reduce the hospital stay and, presumably, overall cost. Preoperative parenteral nutritional support may produce a small absolute reduction in post-operative morbidity, but its cost becomes prohibitive. Preoperative enteral nutritional support, especially if carried out in the home, may be of benefit (using the most optimistic interpretation of a small number of trials); if so, it is an economically defensible intervention. Particular nutrients or diets may have specific effects on certain disease processes. Indirect comparisons have suggested that elemental diets can be used to treat flares of Crohn's disease (perhaps because putative food antigens are removed). However, corticosteroid therapy is more efficacious. Furthermore, it is less expensive to employ 6-mercaptopurine as the next modality in steroid failures. Branched-chain amino acid infusions may have some effect on hepatic encephalopathy, but again, lactulose is less expensive. Nutritional support is one area of medicine in which there has been far more enthusiasm than the data justify. Disease-associated malnutrition probably is a secondary phenomenon, not an important cause of morbidity. The widespread use of this modality cannot be justified in a cost-constrained health care system.

Malabsorption associated with surgical procedures and its treatment

Signs and symptoms of malabsorption after surgical procedures can be subtle and recognized late. This article reviews some of the more common surgical procedures potentially associated with malabsorption and suggests techniques of nutrition intervention. Early recognition, and preferably preventative care, should result in improved patient outcome.

Enteral and parenteral feedings. Guidelines and recommendations

The clinician is confronted with many options in choosing appropriate nutritional support for a patient. Several major issues emerge. 1. Supplemental nutritional support is appropriate in patients who will not be able to take oral calories for more than 7 days. Individuals with preexisting deficits due to lifestyle or disease should have support started more promptly. 2. The use of TPN as a preoperative adjunct in surgical patients appears to be beneficial only to those with severe malnutrition. 3. In the vast majority of patients, the enteral route is preferred. Total parenteral nutrition appears to be beneficial in those with inadequate absorptive capacity, fistula, acute hepatic/renal failure, inflammatory bowel disease, and as an adjunct to cancer therapy. 4. Complications associated with enteral and parenteral nutrition delivery can be minimized by careful attention to detail and adequate monitoring of responses. 5. An exciting area beyond the scope of this monograph is the emergence of the field of "Nutritional Pharmacology" where one manipulates the patient's diet to achieve a desired physiologic result, just as one will change antibiotics or pressors. This will provide an additional tool to the clinician in the treatment of critically ill patients.

Effect of glucose and branched chain amino acid (BCAA) infusion on onset of liver regeneration and plasma amino acid pattern in partially hepatectomized rats

Immediately after 70% hepatectomy, rats were infused via the jugular vein with one of the following solutions: saline, 3% or 8% glucose solution, 3% BCAA solution, 8% Nutramin (17% BCAA) or 8% Nutramin enriched with BCAA (47% BCAA). Rats were killed 18, 21, 24 and 30 h after partial hepatectomy. The course of liver regeneration was assessed from incorporation of labeled thymidine into DNA and from hepatocyte mitotic activity. After partial hepatectomy a decrease of glycemia and increase of plasma phenylalanine concentrations were observed. Glucose infusion had a pronounced inhibiting effect on the onset of liver regeneration. The decreased incorporation of labeled thymidine into DNA and the decreased hepatocyte mitotic activity in glucose-infused rats were associated with higher plasma concentrations of tyrosine and phenylalanine. Parenteral administration of 3% BCAA solution and 8% Nutramin enriched with BCAA had a favourable effect on the onset of liver regeneration after partial hepatectomy compared with glucose- and Nutramin-infused groups. In BCAA-infused rats elevated levels of BCAA and decreased concentrations of tyrosine and phenylalanine were noted.

Nutritional support in liver failure

The most important manifestations of advanced liver disease are malnutrition, encephalopathy, and hepatorenal syndrome. Appropriate and optimal nutritional and metabolic support with specially formulated solutions enriched in branched-chain amino acids, together with other advanced treatments such as plasmapheresis, hemofiltration, and continuous arteriovenous hemodialysis, can correct the most important metabolic and clinical aberrations and temporarily improve the quality of life. However, the ultimately poor prognosis of patients with severe liver failure has not been altered significantly to date by the provision of nonspecific or specifically tailored nutrient regimens. The prognosis appears to depend on the arrest, correction, or reversal of the primary pathophysiologic process.

Branched chain amino acids in the management of chronic liver disease. Facts and fantasies

The liver plays a central role in protein and amino acid metabolism. It processes dietary amino acids and reprocesses amino acids released from muscle protein degradation. It utilises amino acids for protein synthesis and gluconeogenesis, regulates the supply of amino acids to peripheral tissues and converts excess amino acids to urea. In patients with liver disease the liver's ability to control both plasma and tissue amino acid fluxes may be seriously disturbed. The resultant changes in amino acid metabolism may be implicated in the genesis of the neuropsychiatric abnormalities and the deterioration in nutritional status commonly observed in patients with hepatic failure. Thus, on theoretical grounds, amelioration of these amino acid abnormalities might benefit patients with liver disease who have hepatic encephalopathy or are malnourished. However, there is, at present, no consensus as to the efficacy, practicality or cost-effectiveness of 'amino acid therapy' in patients with liver disease.

Branched-chain-enriched amino acid solutions in patients with liver failure: an early example of nutritional pharmacology

The use of BCAA in the treatment of hepatic failure has been controversial. Even in retrospect, it is difficult to know why this controversy existed and why it has been so emotional, except for the fact that such a treatment modality has flown in the face of conventional therapy of hepatic encephalopathy, and also, probably more importantly, directly attacked some of the cherished notions of the nature of hepatic encephalopathy. Time and distance have allowed some of the controversy to die down, and as time has elapsed it has become clear that at least in the area of nutritional support of patients with hepatic failure, BCAA are the preferred alternative to treat patients who are otherwise protein intolerant. A recent unbiased review using the techniques of meta-analysis has concluded that the BCAA are efficacious for the treatment of patients with hepatic encephalopathy. Since this manuscript was completed another study has been reported. In this study, it was notable that those patients treated with oral BCAA became neurologically normal, a finding which the authors found very striking.

Branched chain enriched amino acid versus glucose treatment of hepatic encephalopathy. A double-blind study of 65 patients with cirrhosis

We studied the effects of infusion of a branched chain enriched amino acid mixture versus glucose on acute hepatic encephalopathy in patients with cirrhosis. Sixty-five patients were randomly treated with 1 g/kg per day of an amino acid mixture with 40% branched chain contents (32 patients), or isocaloric glucose (33 patients) for a maximum of 16 days. The regimens further included glucose infusion to a total of 26.5 kcal/kg per day and lactulose. The patients took part in the study for 5-6 days. In each group 17 patients woke up. In the amino acid group eleven died and four developed renal failure. In the glucose group ten died, three developed renal and two respiratory failure, and one remained encephalopathic. The coma score worsened in three of the patients who died in the amino acid group, but in all patients who died in the glucose group. The negative nitrogen balance on entry reversed in the amino acid group, but not in the glucose group. Thus, the branched chain enriched amino acid supplement did not change the prognosis for wake-up, but had other effects on the cerebral state and on nitrogen homeostasis.

Nutritional support in surgical practice: Part II

On admission, a group of high-risk patients who are potential candidates for surgery can be identified, in whom prompt initiation of preoperative enteral or parenteral nutrition may reduce postoperative morbidity and mortality irrespective of the nutritional status. Among these are patients with inflammatory bowel disease, gastrointestinal fistulas, and pancreatitis. Substantial nutritional support has little or no direct effect upon the pathogenesis of the disease, but the discontinuance of oral intake may well have a beneficial effect on the basic disease process. Thus, the provision of enteral or parenteral nutrition gives the patient an optimal opportunity to marshal host defenses in support of healing. In organ system failures, e.g., acute renal failure, liver failure, and pulmonary failure, appropriate nutritional support may assist the patient in coping with the abnormal intermediary metabolism resulting from such failure until satisfactory organ system function returns. From this review, it seems reasonably clear that the initially malnourished patient is less able to successfully withstand the adverse effects of vigorous therapy and/or severe illness than is the well-nourished individual. Hence, correction of malnutrition, either before initiating therapy or concomitant with the treatment, is very likely to be beneficial.

Parenteral nutrition in patients with liver cirrhosis. Effects on circulating levels of glucose and hormones and on cerebral function

The effects of 2 and 5 days of total parenteral nutrition (TPN; 70 g amino-acids, 100 g fat, 150 g glucose) on carbohydrate, fat and amino-acid levels and on cerebral function were investigated in 10 patients with alcoholic cirrhosis and 7 age-matched healthy controls. The results were compared to those after a standardised oral diet. During TPN, glucose concentrations increased slightly in both groups. Insulin concentrations also rose in both groups, but the rise was more pronounced in the patients, resulting in a 10-fold difference between the two groups after 6.5 hours (patients: 281 +/- 81 U/l; controls: 28 +/- 5 U/l; p < 0.02). Glucagon increased significantly during TPN in the patients only (33%, p < 0.05). Similar but less pronounced patterns were observed after the oral diet. The basal concentrations of free fatty acids and 3-OH-butyrate were higher in the patients than in the controls. However, during both oral and parenteral nutrition, the concentrations fell in both groups. For 3-OH-butyrate the difference between the groups disappeared, while the free fatty acid levels remained higher in the patients throughout the TPN administration. Basal triglyceride levels were similar in patients and controls and rose to a similar extent in both groups during TPN. Plasma amino-acid concentrations were typical for cirrhotic patients in the basal state: low levels of the branched-chain amino-acids (BCAA) and high concentrations of the aromatic amino-acids (AAA). During TPN BCAA, as well as AAA, increased in both patients and controls, resulting in unaltered BCAA AAA ratio. All patients performed poorly on psychometric tests (Number Connection Tests A and B; Digit Symbol) before the study, indicating subclinical encephalopathy. However, no deterioration was observed in any of the tests during five days of TPN. Similarly, EEG and visual evoked potentials were unchanged during the study, demonstrating that patients with severe alcoholic liver disease tolerate a balanced intravenous nutrition without adverse effects on cerebral function.

Parenteral nutrition with branched-chain amino acids in hepatic encephalopathy. A meta-analysis

Meta-analytic methods were applied to review clinical trials published in English that have assessed the efficacy of parenteral nutrition for cirrhotic patients with acute hepatic encephalopathy. Modified amino acid solutions containing increased amounts of branched-chain amino acids were used as part of the treatment regimen in all studies. Pooled analysis of five randomized controlled studies showed a highly significant improvement in mental recovery (p less than 0.001) from high-grade encephalopathy over follow-up times varying from 5 to 14 days. The significance level of the treatment effect did not change when the analysis was repeated using alternative methods of counting and attributing events in these trials. Sharp differences in direction of treatment effect precluded pooling case fatality data. Two studies reported an increased risk of death in the treatment group. Two others showed a clear benefit from administration of parenteral nutrition: the aggregate relative risk reduction was 0.59 (95% confidence interval: 0.23-0.80, p = 0.002). Addition of unpublished data from a third positive study increased the relative risk reduction to 0.82 (p less than 0.0001), and the most conservative interpretation of the published data still yielded a significant reduction in mortality (p = 0.023). However, given the uncertainty about effects on mortality and short follow-up times in all studies, a confirmatory randomized controlled trial with longer follow-up periods is warranted.