Liver function tests in patients receiving parenteral nutrition

Approximately 50% of acute intestinal failure (AIF) patients on short-term parenteral nutrition (PN) have intestinal failure-associated liver disease (IFALD) without effect on hospital length of stay and mortality

INTRODUCTION

Patients with intestinal failure (IF) are often dependent on PN for provision of calories and nutrients for survival. Similar to chronic intestinal failure (CIF) patients, those who have AIF are also at risk of IFALD, which is a poorly understood but potentially fatal condition. The local incidence of IFALD amongst AIF patients is not known.

OBJECTIVES

The primary objective of this study was to determine the incidence of IFALD in AIF patients on short-term PN. Secondary objectives were to analyse patient and PN risk factors of IFALD, and clinical outcomes of length of stay (LOS) and inpatient mortality.

DESIGN

This was a retrospective cross-sectional cohort study of hospitalised adult patients with AIF prescribed with short-term PN. All adult patients aged 21 years and above who received PN for at least 5 consecutive days and had normal liver function tests (LFTs) at the time of PN initiation were included in this study.

RESULTS

A total of 171 patients were enrolled in this study, with 77 (45%) having deranged LFTs at the end of PN therapy and categorised under the IFLAD group. The patient cohort was predominantly male (92 [54%]) and had a median age of 68 years (IQR 59-76). Patients with IFALD at the end of PN therapy had higher diabetes prevalence (36% vs 26%, p = 0.2) and were on PN for a longer duration (median [IQR]: 12 [8-17] vs 8 [6-15] days, p = 0.003) than those without IFALD. There were no significant differences in patient and PN characteristics between the IFLAD and non-IFALD group. The multivariable models showed that the IFALD cohort had longer hospital stays (HR 0.90, 95% CI 0.65-1.23) and lower odds of inpatient death (OR 0.75, 95% CI 0.12-4.60), though both findings are not statistically significant (p = 0.5, 0.7).

CONCLUSION

In this study, IFALD is a common phenomenon in AIF and the incidence was found to be an estimated 50% amongst patients on short-term PN with similar clinical outcomes between the two groups.

A silicone disc for liver retraction in laparoscopic gastrectomy reduces the postoperative increase in the liver enzyme level

PURPOSE

To compare changes in liver enzyme levels on postoperative day 1 between patients with and without silicone disc (SD) use during liver retraction in laparoscopic gastrectomy for gastric cancer and laparoscopic gastric mobilization for esophageal cancer.

METHODS

This prospective randomized controlled phase II trial was conducted between June 30, 2020, and November 30, 2022, to investigate the benefits of using an SD with a Nathanson liver retractor (NLR) compared with those using an NLR in laparoscopic gastrectomy and gastric mobilization. The primary endpoint was the change in transaminase level on postoperative day 1.

RESULTS

A total of 86 patients received randomized assignments and were included in the analysis, with 44 assigned to the SD (-) group and 42 to the SD (+) group. On postoperative day 1, the SD (+) group showed a significantly lower increase in the aspartate aminotransferase levels than the SD (-) group (SD [+], 94.4% vs. SD [-], 179.8%; p = 0.012). Similarly, the SD (+) group showed a significantly lower increase in alanine aminotransferase levels than the SD (-) group (SD [+], 71.6% vs. SD [-], 201.5%; p = 0.014).

CONCLUSION

In laparoscopic gastrectomy, the use of an SD combined with an NLR appears to mitigate postoperative liver dysfunction.

ESPEN guideline on chronic intestinal failure in adults - Update 2023

BACKGROUND & AIMS

In 2016, ESPEN published the guideline for Chronic Intestinal Failure (CIF) in adults. An updated version of ESPEN guidelines on CIF due to benign disease in adults was devised in order to incorporate new evidence since the publication of the previous ESPEN guidelines.

METHODS

The grading system of the Scottish Intercollegiate Guidelines Network (SIGN) was used to grade the literature. Recommendations were graded according to the levels of evidence available as A (strong), B (conditional), 0 (weak) and Good practice points (GPP). The recommendations of the 2016 guideline (graded using the GRADE system) which were still valid, because no studies supporting an update were retrieved, were reworded and re-graded accordingly.

RESULTS

The recommendations of the 2016 guideline were reviewed, particularly focusing on definitions, and new chapters were included to devise recommendations on IF centers, chronic enterocutaneous fistulas, costs of IF, caring for CIF patients during pregnancy, transition of patients from pediatric to adult centers. The new guideline consist of 149 recommendations and 16 statements which were voted for consensus by ESPEN members, online in July 2022 and at conference during the annual Congress in September 2022. The Grade of recommendation is GPP for 96 (64.4%) of the recommendations, 0 for 29 (19.5%), B for 19 (12.7%), and A for only five (3.4%). The grade of consensus is "strong consensus" for 148 (99.3%) and "consensus" for one (0.7%) recommendation. The grade of consensus for the statements is "strong consensus" for 14 (87.5%) and "consensus" for two (12.5%).

CONCLUSIONS

It is confirmed that CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for the underlying gastrointestinal disease and to provide HPN support. Most of the recommendations were graded as GPP, but almost all received a strong consensus.

Parenteral Nutrition, Sepsis, Acute Heart Failure and Hepatotoxic Drugs Are Related to Liver Test Disturbances in Critically Ill Patients

BACKGROUND

Parenteral nutrition (PN) is often associated with liver dysfunction in the ICU, although other factors such as sepsis, acute heart failure (AHF), and hepatotoxic drugs can be equally present. The relative impact of PN on liver dysfunction in critically ill patients is largely unknown.

METHODS

We recorded the presence of pre-existing liver disturbances, AHF, sepsis, daily PN volume, and commonly used hepatotoxic drugs in adult ICU patients, together with daily aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), alkalic phosphatase (AP), total bilirubin (TB), and INR values in patients with three or more PN treatment days. A linear mixed-effects model was used to assess the relative contribution of each liver parameter. Nutritional adequacy was defined as intake/needs.

RESULTS

We included 224 ICU patients with PN treatment lasting more than 3 days between 1 January 2017 and 31 December 2019. For AST, pre-existing liver disturbances (+180% ± 11%) and the presence of AHF (+75% ± 14%) were the main predictors of deterioration, whereas PN volume caused only a limited increase of 14% ± 1%/L. Similar results were observed for ALT. GGT, INR, and TB are mainly influenced by the presence of sepsis/septic shock and pre-existing liver disturbances, with no impact of PN or hepatotoxic drugs. Carbohydrate intake exceeded recommendations, and protein and lipid intake were insufficient in this study cohort.

CONCLUSIONS

Liver test disturbances in ICU patients on PN are multifactorial, with sepsis and AHF having the highest influence, with only limited impact from PN and hepatotoxic drugs. Feeding adequacy can be improved.

Cohort Multicenter Study on the Role of Medications in Parenteral Nutrition-Related Alteration of Liver Function Tests in Adults

BACKGROUND

Our objective was to assess in non-critically-ill adult inpatients receiving parenteral nutrition (PN) the risk of developing liver function test (LFT) alterations when receiving concomitant possibly hepatotoxic medications or others reported to improve LFTs during PN.

METHODS

A multicenter retrospective analysis of prospectively collected data was performed on patients receiving PN. Two groups were recruited: group LALT (patients with any LFT alterations during PN), and group NOLALT (patients without such alterations). Exclusion criteria were previous sepsis, shock, renal failure, hyperglycemia, LFT alteration, or biliopancreatic surgical procedures. Medications were classified into 2 categories: medications reported to improve LFTs during PN (n = 8) and possibly hepatotoxic medications (n = 54), including a subgroup of possibly highly hepatotoxic medications (n = 30).

RESULTS

The study included 200 patients, 136 (68.0%) in the LALT group. The groups differed in the number of patients requiring surgical intervention ≤7 days before PN (LALT, 94 [69.1%]; NOLALT, 29 [45.3%]; P < .002) and those receiving possibly hepatotoxic medications (LALT, 126 [92.6%]; NOLALT, 45 [70.3%]; P < .001). Variables in the final Cox regression model were possibly hepatotoxic medications, odds ratio (OR) 3.310 (1.678-6.530); surgical intervention prior to PN, OR 1.861 (1.277-2.711); baseline triglyceridemia, OR 1.005 (1.001-1.009); and creatinine, OR 1.861 (1.043-3.323).

CONCLUSIONS

Patients who received PN and concomitantly possibly hepatotoxic medications had a 3-fold risk of developing LFT alterations. Medications reported to improve LFTs had no effect. The use of possibly hepatotoxic medications during PN was associated with LFT alterations.

Effects of cyclic parenteral nutrition on parenteral-associated liver dysfunction parameters

Introduction

One of the most common complications of parenteral nutrition (PN) is liver dysfunction (LD). Therapeutic approaches for LD include, among others, administering cyclic parenteral nutrition (cPN), allowing some hours for metabolic rest. The purpose of this study was to evaluate the effectiveness of cPN in treating PN-associated LD.

Materials and methods

A retrospective observational study was carried out at the Costa del Sol Hospital in Spain between 2013 and 2014. The study involved inpatients ≥18 years old prescribed with cPN due to the development of PN-associated LD. The hepatic biochemical parameters measured at baseline and after completion of cPN included aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP) and total bilirubin (TB). Quantitative values (age, biochemical parameters) were compared using matched Student’s t-test; the mean change in qualitative variables (sex, indication of PN, hepatic comorbidities, presence of insulin in cPN, infection during cPN, management of LD prior to cPN administrarion) was estimated using Mann-Whitney U test, and bivariate correlation between quantitative variables was determined by Spearman’s coefficient of correlation.

Results

Thirty-seven patients met inclusion criteria. All hepatic function parameters except ALP improved after the administration of cPN, with statistically significant differences (p < 0.05) in AST GGT and TB.

Conclusion

cPN improves PN-associated LD by restoring abnormal AST, GGT, and BT levels to normal, and reducing ALT levels close to normal. The results obtained suggest that the administration of cPN is effective in reverting PN-associated LD.

Structured Triglyceride Emulsions in Parenteral Nutrition

Over the past 3 decades, various concepts for IV fat emulsions (IVFE) have been developed. A randomized, structured-lipid emulsion based on an old technology has recently become available. This structured-lipid emulsion is produced by mixing medium-chain triglycerides and long-chain triglycerides, then allowing hydrolysis to form free fatty acids, followed by random transesterification of the fatty acids into mixed triglyceride molecules. Studies in animals have shown an improvement in nitrogen balance with the use of these lipid emulsions. Only 8 human clinical studies with these products have been performed. The results of these human clinical studies have been less promising than the animal studies; however, an improvement in nitrogen balance and lipid metabolism exceeds results associated with infusion of long-chain triglycerides (LCT) or a physical mixture of long-chain triglycerides and medium-chain triglycerides (LCT-MCT). Structured-lipid emulsion seems to induce less elevation in serum liver function values compared with standard IVFEs. In addition, structured-lipid emulsions have no detrimental effect on the reticuloendothelial system. Further studies are necessary in order to recommend the use of structured-lipid emulsions. The clinical community hopes that chemically defined structured triglycerides will make it possible to determine the distribution of specific fatty acids on a specific position on the glycerol core and therefore obtain specific activity for a specific clinical situation.

Liver Failure Is Uncommon in Adults Receiving Long-Term Parenteral Nutrition

BACKGROUND

Abnormal liver enzymes and endstage liver disease are reported to occur in 25%-100% and 15%-40% of adult patients receiving long-term parenteral nutrition (PN), respectively. The purpose of this historic cohort study was to investigate the incidence of and possible factors leading to the development of liver disease in our large home PN population.

METHODS

All patients on home PN for at least 6 months from July 1991 through June 2002 were eligible. Patients were excluded if they had active malignancy, underlying liver disease, or exposure to a hepatotoxin. The presence of PN-associated liver disease was only considered if test results were elevated on more than 1 occasion over at least 6 or more months. The severity of liver-associated enzymes was based on the degree of elevation and was stratified as mild (<2 times normal), moderate (2-5 times normal), and severe (>5 times normal). Severe liver dysfunction was defined as having all of the following criteria: total bilirubin >3 mg/dL; albumin <3.2 g/dL; and prothrombin time >3 seconds prolonged. A cumulative logit model was used to compare age, gender, underlying disease, PN indication, and PN formulas in patients with normal vs abnormal laboratory test results.

RESULTS

Two hundred eight patients received PN for more than 6 months, 36 had exclusion criteria, and 10 could not be analyzed, because of incomplete laboratory test results, leaving 162 in the study group. The average PN duration was 2.14 +/- 2.19 years (maximum, 10.28 years). Abnormal liver tests occurred in 154 patients, with most having a moderate elevation of alkaline phosphatase or aspartate aminotransferase; severe liver dysfunction occurred in 7 patients; 1 patient had completely normal liver enzymes. On average, patients received a PN formula that was high in amino acids (1.45 +/- 0.65 g/kg/d), modest in energy (24.7 +/- 13.4 kcal/kg/d), and in most cases with enough lipid emulsion to meet essential fatty acid requirements (0.28 +/- 0.25 g/kg/d). Only female gender was found to be associated with a greater likelihood of liver failure (p = .02). There was a trend toward a greater amount of total calories, dextrose calories, and duration of PN exposure leading to the development of severe liver dysfunction.

CONCLUSIONS

When long-term PN is given with a modest amount of total energy and a minimal amount of lipid emulsion, abnormal liver enzymes are common, but severe liver dysfunction is unusual.

ESPEN guidelines on chronic intestinal failure in adults

BACKGROUND & AIMS

Chronic Intestinal Failure (CIF) is the long-lasting reduction of gut function, below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth. CIF is the rarest organ failure. Home parenteral nutrition (HPN) is the primary treatment for CIF. No guidelines (GLs) have been developed that address the global management of CIF. These GLs have been devised to generate comprehensive recommendations for safe and effective management of adult patients with CIF.

METHODS

The GLs were developed by the Home Artificial Nutrition & Chronic Intestinal Failure Special Interest Group of ESPEN. The GRADE system was used for assigning strength of evidence. Recommendations were discussed, submitted to Delphi rounds, and accepted in an online survey of ESPEN members.

RESULTS

The following topics were addressed: management of HPN; parenteral nutrition formulation; intestinal rehabilitation, medical therapies, and non-transplant surgery, for short bowel syndrome, chronic intestinal pseudo-obstruction, and radiation enteritis; intestinal transplantation; prevention/treatment of CVC-related infection, CVC-related occlusion/thrombosis; intestinal failure-associated liver disease, gallbladder sludge and stones, renal failure and metabolic bone disease. Literature search provided 623 full papers. Only 12% were controlled studies or meta-analyses. A total of 112 recommendations are given: grade of evidence, very low for 51%, low for 39%, moderate for 8%, and high for 2%; strength of recommendation: strong for 63%, weak for 37%.

CONCLUSIONS

CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for both the underlying gastrointestinal disease and to provide HPN support. The rarity of the condition impairs the development of RCTs. As a consequence, most of the recommendations have a low or very low grade of evidence. However, two-thirds of the recommendations are considered strong. Specialized management and organization underpin these recommendations.

Phase IV prospective clinical study to evaluate the effect of taurine on liver function in postsurgical adult patients requiring parenteral nutrition

BACKGROUND

Taurine's role in bile acid metabolism and anti-inflammatory activity could exert a protective effect on hepatobiliary complications associated with parenteral nutrition (PN). In this study, the effects of 2 amino acid solutions, with and without taurine, on liver function administered to nonacutely ill postsurgical patients as part of a short-term PN regimen were prospectively compared.

METHODS

Adult patients randomly received (double-blind) Tauramin 10% or a standard PN solution without taurine as the control (1.5 g amino acid/kg body weight [bw]/d; infusion rate of ≤4 mg glucose/kg bw/d) for a period of 5-30 days. γ-Glutamyl transpeptidase (GGT) and other indicators of liver function, glucose metabolism, lipid profile, inflammation markers, and treatment safety data were collected.

RESULTS

Thirty-five patients receiving taurine PN and 39 receiving control PN were enrolled (intention-to-treat [ITT] population). Most patients (n = 62) discontinued after day 7 of follow-up (per-protocol [PP] population: n = 24 and n = 27, respectively). ITT patients with high GGT values after 5 days of PN comprised 68.6% and 64.1%, respectively. The mean change in GGT values with respect to the baseline values was 167 ± 192 and 157 ± 185 IU/L, respectively. Low-density lipoprotein (LDL) cholesterol levels after 7 days of PN were significantly decreased in the taurine PN group of PP patients (-2.83 ± 30.9 vs 23.9 ± 27.0 mg/dL for control PN; P < .05). None of the adverse events reported (taurine PN: n = 6; control PN: n = 7) were treatment related.

CONCLUSION

PN solutions with and without taurine had similar effects on liver function parameters, except for an LDL reduction in PN with taurine, when administered to nonacutely ill postsurgical patients in the short term (5-7 days).

What really causes necrotising enterocolitis?

Background. One of the most serious gastrointestinal disorders occurring in neonates is necrotising enterocolitis (NEC). It is recognised as the most common intra-abdominal emergency and is the leading cause of short bowel syndrome. With extremely high mortality and morbidity, this enigmatic disease remains a challenge for neonatologists around the world as its definite aetiology has yet to be determined. As current medical knowledge stands, there is no single well-defined cause of NEC. Instead, there are nearly 20 risk factors that are proposed to increase the likelihood of developing NEC. Aims and Objectives. The aim of this project was to conduct a comprehensive literature review around the 20 or so well-documented and less well-documented risk factors for necrotising enterocolitis. Materials and Methods. Searches of the Medline, Embase, and Science direct databases were conducted using the words "necrotising enterocolitis + the risk factor in question" for example, "necrotising enterocolitis + dehydration." Search results were ordered by relevance with bias given to more recent publications. Conclusion. This literature review has demonstrated the complexity of necrotising enterocolitis and emphasised the likely multifactorial aetiology. Further research is needed to investigate the extent to which each risk factor is implicated in necrotising enterocolitis.

Jaundice increases the rate of complications and one-year mortality in patients with hypoxic hepatitis

Hypoxic hepatitis (HH) is the most frequent cause of acute liver injury in critically ill patients. No clinical data exist about new onset of jaundice in patients with HH. This study aimed to evaluate the incidence and clinical effect of jaundice in critically ill patients with HH. Two hundred and six consecutive patients with HH were screened for the development of jaundice during the course of HH. Individuals with preexisting jaundice or liver cirrhosis at the time of admission (n = 31) were excluded from analysis. Jaundice was diagnosed in patients with plasma total bilirubin levels >3 mg/dL. One-year-survival, infections, and cardiopulmonary, gastrointestinal (GI), renal, and hepatic complications were prospectively documented. New onset of jaundice occurred in 63 of 175 patients with HH (36%). In patients who survived the acute event of HH, median duration of jaundice was 6 days (interquartile range, 3-8). Patients who developed jaundice (group 1) needed vasopressor treatment (P < 0.05), renal replacement therapy (P < 0.05), and mechanical ventilation (P < 0.05) more often and had a higher maximal administered dose of norepinephrine (P < 0.05), compared to patients without jaundice (group 2). One-year survival rate was significantly lower in group 1, compared to group 2 (8% versus 25%, respectively; P < 0.05). Occurrence of jaundice was associated with an increased frequency of complications during follow-up (54% in group 1 versus 35% in group 2; P < 0.05). In particular, infections as well as renal and GI complications occurred more frequently in group 1 during follow-up.

CONCLUSION

Jaundice is a common finding during the course of HH. It leads to an increased rate of complications and worse outcome in patients with HH.

Home parenteral nutrition support for intestinal failure

Home parenteral nutrition is a life-saving treatment for many patients with intestinal failure. Expert placement and care of the vascular access device reduces the incidence of access-related complications. Careful monitoring of fluid, electrolyte, and macronutrient and micronutrient status can minimize major organ dysfunction and metabolic complications. A multidisciplined, integrated nutrition support team can allow patients with intestinal failure who need home parenteral nutrition maintain a near-normal life.

Abnormal liver function tests in the parenteral nutrition fed patient

Liver dysfunction is common in individuals receiving parenteral nutrition (PN) and particularly in neonates and infants. Abnormalities of liver function tests in patients receiving short term PN are usually transient but in individuals receiving long term PN, substantial liver damage and ultimately end stage liver disease may occur. The aetiology is complex, involving a large number of patient related and nutrition related factors. The terminology intestinal failure associated liver disease (IFALD) is therefore more appropriate than PN associated liver disease. Effort should be made to prevent liver dysfunction by managing sepsis, avoiding parenteral overfeeding, employing cyclical parenteral feeding and encouraging enteral nutrition where possible. Intake of soybean based parenteral lipid emulsions should be reduced in individuals with established IFALD, possibly to be replaced by lipid emulsions containing medium chain triacylglycerol, monounsaturated fatty acids or fish oil although larger clinical studies are needed. Similarly, evidence supporting the widespread use of parenteral choline and taurine supplementation in the prevention or treatment of IFALD remains limited. There are more data to support the use of oral antibiotics to treat bacterial overgrowth and oral ursodeoxycholic acid in neonates. Ultimately, severe IFALD may necessitate referral for small intestine and/or liver transplantation.

ESPEN Guidelines on Parenteral Nutrition: home parenteral nutrition (HPN) in adult patients

Home parenteral nutrition (HPN) was introduced as a treatment modality in the early 1970s primarily for the treatment of chronic intestinal failure in patients with benign disease. The relatively low morbidity and mortality associated with HPN has encouraged its widespread use in western countries. Thus there is huge clinical experience, but there are still few controlled clinical studies of treatment effects and management of complications. The purpose of these guidelines is to highlight areas of good practice and promote the use of standardized treatment protocols between centers. The guidelines may serve as a framework for development of policies and procedures.

Recent advances in the management of intestinal failure-associated liver disease

PURPOSE OF REVIEW

To summarize the current management of intestinal failure-associated liver disease (IFALD) by reviewing recent advances in our understanding of the condition and the effects of different therapeutic approaches.

RECENT FINDINGS

The importance of gastrointestinal length and continuity in the aetiology and treatment of IFALD has been demonstrated in both retrospective and interventional cohorts. A mechanism for the cholestatic effect of soy-based lipid has been described, and the clinical use of alternative lipid sources has demonstrated benefit. Prevention of IFALD has been shown with the use of erythromycin in neonates, and reversal of established IFALD has been demonstrated with isolated intestinal transplantation.

SUMMARY

A greater understanding of the mechanisms of IFALD has led to promising interventions to prevent and treat the condition. Other possible therapeutic targets require more formal evaluation, and further work is required to develop noninvasive tools for the assessment and prognosis of IFALD that will guide treatment and help in the selection of patients and timing of transplantation.

[Risk factors of the hepatic dysfunction associated with parenteral nutrition]

BACKGROUND AND OBJECTIVE

The objective of this study is to describe the incidence of hepatic dysfunction (HD) in our hospital and evaluate the possible risk factors associated with HD development as an improvement of the caring process received by patients treated with parenteral nutrition (PN).

PATIENTS AND METHOD

A prospective study of patients (n=994) who required PN during the period 2000-2004. HD is the identification of an increase above 1,5 of the top reference value of alkaline phosphatase (40-450U/l) and gamma glutamyl transpeptidase (11-49U/l) associated with an increase of transaminases (5-32U/l) and a total bilirrubin higher than 1,2mg/dl.

RESULTS

The incidence of HD was 4,9% (n=49). Days with PN were significantly higher in the HD group: median (interquartile range): 30 (20-59) vs 15 (8-25) days (p<0.001). In the univariated HD analysis, the variables that reached significant odds ratio were: the critical patient condition, the PN duration, the total calorie contribution higher than 25kcal/kg, to exceed 3g of carbohydrates/kg, to administer more than 0.8g/kg of lipids and to exceed 0.16g of nitrogen/kg. In the multivariated analysis, the variables selected as independent risk factors were: to exceed 3 weeks of PN, to be a critical patient and a contribution over 0.16g of nitrogen/kg.

CONCLUSIONS

The present profiles of the patients who will develop HD are those with prolonged PN. These patients undergo processes and critical therapy, where the specialists must monitor, not only calorie contribution, carbohydrates or lipids, but proteins as well.

Managing liver dysfunction in parenteral nutrition

Parenteral nutrition is life saving in patients with intestinal failure but liver dysfunction is commonly encountered, especially in neonates. Although abnormal liver function tests associated with short-term parenteral nutrition are usually benign and transient, liver dysfunction in both children and adults receiving long-term parenteral nutrition can progress to end-stage liver disease and liver failure. The aetiology of parenteral nutrition-associated liver disease is complex and multifactorial, with a range of patient, disease and nutrition-related factors implicated. Sepsis is of particular importance, as is the lack of enteral nutrition and overfeeding with intravenous glucose and/or lipid. Deficiencies of a number of amino acids including choline and taurine have also been implicated. Management of hepatic dysfunction in parenteral nutrition should initially focus on preventing its occurrence. Sepsis should be managed appropriately, enteral nutrition should be encouraged and maximised where possible and parenteral overfeeding should be avoided. Provision of parenteral lipid should be optimised to prevent the adverse effects of both deficiency and excess, and cyclical rather than continuous parenteral feeding should be administered. There is some evidence of benefit in neonates from oral antibiotics to prevent intestinal bacterial overgrowth and from oral ursodeoxycholic acid, but less to support their use in adults. Similarly, data to support widespread use of parenteral choline or taurine supplementation are lacking at present. Ultimately, severe parenteral nutrition-associated liver disease may necessitate referral for small intestine and/or liver transplantation.

Parenteral nutrition related hepato-biliary disease in adults

Parenteral nutrition is a life-saving therapy in patients with intestinal failure. One of the major causes of morbidity and mortality in patients receiving long-term total parenteral nutrition (TPN) is liver disease. Early on, there is steatosis, which can evolve to steatohepatitis and eventually to cholestasis of varying severity. The etiology of parenteral nutrition related liver disease is multifactorial. Provision of excess calories in the TPN solution, along with lipids administered >1 g/kg are thought to increase the risk of parenteral nutrition related liver disease. Other factors such as nutrient deficiencies and nutrient toxicities may also play a role in the pathogenesis of liver disease, along with sepsis and the lack of enteral stimulation. Non-pharmacological management strategies for TPN-related liver disease include enteral stimulation, optimal TPN composition, and avoidance of excess carbohydrate and lipid calories. Pharmacological therapy with ursodeoxycholic acid and antibiotic therapy to reduce the risk of bacterial translocation and sepsis should be considered. Early referral for transplantation should be considered in patients with evidence of portal hypertension. This review focuses on the clinical aspects, pathogenesis, and management strategies of parenteral nutrition-related liver disease in adult patients.

Liver dysfunction associated with artificial nutrition in critically ill patients

INTRODUCTION

Liver dysfunction associated with artificial nutrition in critically ill patients is a complication that seems to be frequent, but it has not been assessed previously in a large cohort of critically ill patients.

METHODS

We conducted a prospective cohort study of incidence in 40 intensive care units. Different liver dysfunction patterns were defined: (a) cholestasis: alkaline phosphatase of more than 280 IU/l, gamma-glutamyl-transferase of more than 50 IU/l, or bilirubin of more than 1.2 mg/dl; (b) liver necrosis: aspartate aminotransferase of more than 40 IU/l or alanine aminotransferase of more than 42 IU/l, plus bilirubin of more than 1.2 mg/dl or international normalized ratio of more than 1.4; and (c) mixed pattern: alkaline phosphatase of more than 280 IU/l or gamma-glutamyl-transferase of more than 50 IU/l, plus aspartate aminotransferase of more than 40 IU/l or alanine aminotransferase of more than 42 IU/l.

RESULTS

Seven hundred and twenty-five of 3,409 patients received artificial nutrition: 303 received total parenteral nutrition (TPN) and 422 received enteral nutrition (EN). Twenty-three percent of patients developed liver dysfunction: 30% in the TPN group and 18% in the EN group. The univariate analysis showed an association between liver dysfunction and TPN (p < 0.001), Multiple Organ Dysfunction Score on admission (p < 0.001), sepsis (p < 0.001), early use of artificial nutrition (p < 0.03), and malnutrition (p < 0.01). In the multivariate analysis, liver dysfunction was associated with TPN (p < 0.001), sepsis (p < 0.02), early use of artificial nutrition (p < 0.03), and calculated energy requirements of more than 25 kcal/kg per day (p < 0.05).

CONCLUSION

TPN, sepsis, and excessive calculated energy requirements appear as risk factors for developing liver dysfunction. Septic critically ill patients should not be fed with excessive caloric amounts, particularly when TPN is employed. Administering artificial nutrition in the first 24 hours after admission seems to have a protective effect.

Parenteral nutrition-associated liver disease and the role for isolated intestine and intestine/liver transplantation

Parenteral nutrition-associated liver disease (PNALD) is the most devastating complication of long-term parenteral nutrition therapy. Because its progression is typically insidious and its long-term consequences are generally underappreciated, PNALD is often recognized too late, when liver injury is irreversible. When end-stage liver disease (ESLD) develops in these patients, most potential interventions are futile and transplantation of both an intestine and a liver becomes the only viable option, despite the relatively poor outcomes associated with this combined procedure. Although likely multifactorial in origin, the etiology of PNALD is poorly understood. Early clinical intervention with a combination of nutritional, medical, hormonal, and surgical therapies can be effective in preventing liver disease progression. If these interventions fail, intestinal transplantation should be performed expeditiously before development of ESLD mandates simultaneous inclusion of a liver graft as well.

Glucose-lipid ratio is a determinant of nitrogen balance during total parenteral nutrition in critically ill patients: a prospective, randomized, multicenter blind trial with an intention-to-treat analysis

OBJECTIVE

Protein sparing, the major goal of nutritional support, may be affected by the glucose/lipid ratio. This study in critically ill patients compared the efficacy and tolerance of two isocaloric isonitrogenous total parenteral nutritions (TPN) having different glucose/lipid ratios.

DESIGN

Multicentric prospective randomized study.

PATIENTS

47 patients with SAPS I score higher than 8 and requiring exclusive TPN.

INTERVENTIONS

Patients received glucose/lipid ratios of 50/50 or 80/20. For 7 days all patients received 32 glucidolipidic kcal/kg and 0.27 g/kg nitrogen daily. All-in-one bags were prepared using industrial mixtures and a fat emulsion.

MEASUREMENTS AND RESULTS

We determined TPN efficacy by nitrogen balance, urinary 3-methylhistidine/creatinine ratio, transthyretin and tolerance by glycemia, and liver enzymes. After controlling for five variables with significant effects, patients receiving the 50/50 ratio during TPN had significantly higher nitrogen balance than those receiving the 80/20 ratio. The daily difference in mean nitrogen sparing effect in favor of the latter group was 1.367 g (95% CI 0.0686-2.048). Glycemia on day 4 and gamma-glutamyltranspeptidase on day 8 were higher in group receiving the the 80/20 ratio.

CONCLUSIONS

In critically ill patients TPN at a glucose/lipid ratio of 80/20 ratio induces a small nitrogen sparing effect compared to the ratio of 50/50, at the expense of poorer glycemic control. The clinical significance is unclear.

Rapid Acute Amiodarone-Induced Hepatotoxicity in a Burn Patient

Acute burn and trauma patients have a higher frequency of cardiac arrhythmias than would be expected for noncardiac-hospitalized patients. Amiodarone is an effective, commonly used drug for cardiac arrhythmias in this patient population. We present a 54-year-old white man treated in the burn intensive care unit for 70% TBSA burns. The patient developed an acute increase in liver enzymes within days of starting intravenous amiodarone for the control of atrial fibrillation. A full radiologic hepatobiliary investigation did not reveal a source for hepatotoxicity. Discontinuation of amiodarone resulted in a rapid decrease in liver enzyme levels to baseline values. It is important to identify amiodarone as a potential cause of severe hepatotoxicity in burn patients, despite short duration of use and a low cumulative dose.

Prevalence, outcome and associated factors of deranged liver function tests in patients on home parenteral nutrition

INTRODUCTION

The prevalence of deranged liver function tests (LFT) in patients on long-term home parenteral nutrition (HPN) is poorly documented. The aim of our study was to document the prevalence of this complication and possible associated factors.

METHOD

Retrospective analysis of case notes of 107 patients on HPN was performed. Deranged LFT was defined as any biochemical parameter of LFT that is 1.5 times above the reference range.

RESULTS

There were 39 males and the median age was 51 (range 20-73) years old. Median duration of HPN was 40 (range 6-252) months. Underlying diagnoses were Crohn's disease (40%), ischaemic bowel disease in 28.1% (arterial or venous), post-surgical intestinal adhesion and fistula (16.9%) and others (21.7%). The mean energy intake from HPN was 1003+/-544(SD) kcal/day with 845+/-474 kcal/day from glucose, 157+/-127 kcal/day from fat and mean nitrogen intake was 6.2+/-3.6 g/day. Raised alkaline phosphatase (mean 197+/-143(SD)U/L) was the most common abnormality (40 patients). Two patients had hyperbilirubinaemia; one patient had hereditary spherocytosis and in the other patient, the cause could be attributed to HPN with bilirubin of 54 micromol/l. Fifty-one patients (47.7%) had deranged LFT as judged from raised parameters on LFT. Abnormality in LFT was transient in nine patients. For the other 42 patients (39%), abnormalities in LFT remained stable for median duration of follow-up of 18.5 (range 3-180) months. No patients developed decompensated liver disease. On univariate analysis, length of small bowel of less than 100 cm, a higher total caloric intake from HPN (mean 1117+/-486 kcal against 907+/-576 kcal, P<0.05), and higher daily caloric intake from HPN in relation to calculated daily energy requirement (70+/-32% against 57+/-36%) were noted to be significantly associated with deranged LFT. However, on multivariate analysis, length of small bowel of less than 100 cm was the only significant variable for deranged LFT.

CONCLUSION

Our finding showed the prevalence of deranged LFT to be 39% and raised alkaline phosphatase was the most common abnormality. Length of small bowel of less than 100 cm was found to be a significant independent variable for deranged LFT and the reason for this observation could be due to higher parenteral caloric intake. In our experience, LFT abnormalities are associated with a good prognosis as none of the patients developed decompensated liver disease.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

Persistent inflammation and immune activation contribute to cholestasis in patients receiving home parenteral nutrition

Liver disease is frequent in patients taking home parenteral nutrition (HPN), but its cause remains unclear. Ongoing inflammation was implicated in HPN-associated cholestasis, so we examined the relation between liver-enzyme concentrations and circulating inflammatory and immune markers in these patients. In 17 HPN patients and 10 age- and sex-matched control subjects, we examined erythrocyte sedimentation rate, blood neopterin, soluble interleukin (IL)--2 receptors, circulating tumor necrosis factor-alpha, IL-6, aspartate and alanine aminotransferases, alkaline phosphatases, and gamma-glutamyltranspeptidase (GGT) concentrations. Fourteen of 17 patients had abnormal liver function tests with an increase in alkaline phosphatases (P < 0.001), gamma-glutamyltranspeptidase (P < 0.01), and aspartate aminotransferase (P < 0.01). Alkaline phosphatases were positively correlated to erythrocyte sedimentation rate, neopterin, tumor necrosis factor-alpha, and IL-6. gamma-Glutamyltranspeptidase was positively linked to tumor necrosis factor-alpha and soluble IL-2 receptors. There was no link between aminotransferases and inflammatory parameters. Liver-enzyme concentrations were correlated to the amount of total intravenous calories and calories originating from carbohydrates but not to infused lipids (median infused lipids x kg(-1) body weight x d(-1) = 0.62 g) in contrast to recently published data. Our results confirmed that the number of infused calories contributes to liver toxicity in HPN patients and strongly suggested that sustained inflammation is probably a key factor in worsening HPN-associated cholestasis.

Abnormal liver function tests in a patient fed with total parenteral nutrition and treated with octreotide

Octreotide is a long-acting analog of somatostatin, a hypothalamic release-inhibiting hormone. It is sometimes used therapeutically to relieve symptoms associated with acromegaly and gastroenteropancreatic endocrine tumors. It has also been used in the treatment of short-bowel syndrome and gastrointestinal and biliary fistulae. We report a patient with biliary leakage due to Marizzi's syndrome treated with total parenteral nutrition and octreotide who developed abnormal liver function tests that improved when the two treatments were stopped. We also review the literature regarding abnormal liver function tests in patients on total parenteral nutrition.

TPN update: making each visit count

Caring for patients on TPN is a challenge for the home care nurse. These patients may present with either a short- or long-term need for TPN but in either case, the impact on daily life related to administration and monitoring of this complex infusion therapy is significant for both patients and their caregivers. The risks and complications of TPN can be serious. Nurses must possess expert knowledge of TPN administration and a high level of competence in assessment and monitoring of patients on TPN. Patients and caregivers will learn technical procedures in the home that produce anxiety in graduate nurses! The nurse must also possess skill and confidence in teaching patients to effectively administer, manage, and incorporate TPN infusion therapy into their lives.

Abnormal liver functions as a result of total parenteral nutrition in a patient with short-bowel syndrome

The pathogenesis of total parenteral nutrition (TPN)-induced liver cholestasis is poorly understood. Cholestasis generally occurs late in TPN therapy in association with elevated serum alkaline phosphatase and total bilirubin concentrations. Such factors as preexisting medical conditions, excessive nutrient infusion, amino-acid deficiency, absence of enteral stimulation, protracted duration of therapy, continuous infusion schedule, and hypoalbuminemia have all been suggested as possible etiologies. Various treatments have been proposed for the correction of TPN-induced cholestasis including administration of bile salt and antimicrobial therapies. To avoid potential hepatic complications associated with TPN, certain preventive measures can be considered. Administration of energy substrates should not be excessive. A mixed-fuel system that includes lipids should be implemented. TPN should be cycled if it will be used long term, and initiation of enteral nutrition should begin as soon as possible.

Factors associated to hypermanganesemia in patients receiving home parenteral nutrition

BACKGROUND

Home parenteral nutrition (HPN) patients often present hypermanganesamia.

AIM

To examine which factors may be associated to hypermanganesemia in HPN patients.

METHODS

Plasma manganese (Mn), liver function tests, C-reactive protein concentrations, erythrocyte sedimentation rate (ESR), tumor necrosis factor-alpha (TNF- alpha), interleukin-6, soluble receptors of interleukin-2, and blood neopterin concentrations were determined in 21 HPN patients and 10 healthy controls. Brain magnetic resonance imaging (MRI) and careful neurologic clinical examination were performed in 11 patients.

RESULTS

Mn concentration was higher in HPN patients than controls (1.96+/-1.1 vs 0.81+/- 0.4 microg/L;P<0.001) and positively correlated to the amount of parenteral nutrition (PN) supply, transaminases and alkaline phosphatase (r=0.53, P<0.0001) concentrations, as well as to ESR (r=0.61, P<0.0001), TNF- alpha and blood neopterin. The amount of calories provided by PN was positively correlated to inflammatory markers and liver parameters. All patients investigated by MRI showed hyperintense basal ganglia on T1-weighted images suggesting brain Mn deposition. Only one had slight clinical extrapyramidal symptoms.

CONCLUSION

In HPN patients, sustained inflammation may facilitate hypermanganesemia through 1. cholestatic liver disease and thereby decreased Mn biliary excretion, 2. high nutritional requirements (responsible for increased Mn supply), and/or 3. modified Mn metabolism or body distribution. Neurologic complications appeared marginal whereas Mn brain deposition seems frequent.

Prevalence of liver disease and contributing factors in patients receiving home parenteral nutrition for permanent intestinal failure

BACKGROUND

Liver cholestasis can be a life-threatening complication during home parenteral nutrition and may lead to combined liver-intestinal transplantation.

OBJECTIVE

To assess the prevalence of home parenteral nutrition-related liver disease and its contributing factors in patients with permanent intestinal failure.

DESIGN

Prospective cohort study.

SETTING

Two approved home parenteral nutrition centers.

PATIENTS

90 patients with permanent intestinal failure who were receiving home parenteral nutrition were enrolled from 1985 to 1996.

INTERVENTION

Clinical, biological, endoscopic, and ultrasonographic follow-up. Histologic examination of the liver was done in 57 patients (112 liver biopsies).

MEASUREMENTS

The Kaplan-Meier method was used to determine the actuarial occurrence of chronic cholestasis and complicated home parenteral nutrition-related liver disease (bilirubin level > or =60 micromol/L [3.5 mg/dL], factor V level < or =50%, portal hypertension, encephalopathy, ascites, gastrointestinal bleeding, or histologically proven extensive fibrosis or cirrhosis). Contributing factors were assessed by using univariate and multivariate (Cox model) analysis.

RESULTS

58 patients (65%) developed chronic cholestasis after a median of 6 months (range, 3 to 132 months), and 37 (41.5%) developed complicated home parenteral nutrition-related liver disease after a median of 17 months (range, 2 to 155 months). Of these patients, 17 showed extensive fibrosis after 26 months (range, 2 to 148 months) and 5 had cirrhosis after 37 months (range, 26 to 77 months). The prevalence of complicated home parenteral nutrition-related liver disease was 26%+/-9% at 2 years and 50%+/-13% at 6 years. Six patients died of liver disease (22% of all deaths). In multivariate analysis, chronic cholestasis was significantly associated with a parenteral nutrition-independent risk for liver disease, a bowel remnant shorter than 50 cm in length, and a parenteral lipid intake of 1 g/kg of body weight per day or more (omega-6-rich long-chain triglycerides), whereas complicated home parenteral nutrition-related liver disease was significantly associated with chronic cholestasis and lipid parenteral intake of 1 g/kg per day or more.

CONCLUSION

The prevalence of complicated home parenteral nutrition-related liver disease increased with longer duration of parenteral nutrition. This condition was one of the main causes of death in patients with permanent intestinal failure. Parenteral intake of omega-6-rich long-chain triglycerides lipid emulsion consisting of less than 1 g/kg per day is recommended in these patients.

Incidence, prognosis, and etiology of end-stage liver disease in patients receiving home total parenteral nutrition

BACKGROUND

Elevations in liver function tests have been reported in patients receiving total parenteral nutrition (TPN). The clinical aspects of end-stage liver disease (ESLD) associated with the prolonged use of home TPN have not been fully clarified. In previous series patients with duodenocolostomies appeared to be at higher risk than persons with some jejunum or ileum remaining in situ.

METHODS

The records of 42 patients treated with home TPN for more than 1 year were examined. This constituted 283 person-years of home TPN. Patients with duodenocolostomies were examined as a separate group on the basis of the literature experience.

RESULTS

Six of 42 patients who received chronic home TPN had ESLD with 100% subsequent mortality, at an average of 10.8 +/- 7.1 months after the initial bilirubin elevation. Thirteen of 42 patients had superior mesenteric artery or vein thrombosis (SMT) leading to duodenocolostomy. In 8 of these 13 patients with SMT and underlying inflammatory or malignant disorder, 2 had ESLD. The remaining 5 SMT patients who had only minimal liver enzyme elevation over 13.6 +/- 6.7 (range 3 to 19) years of home TPN were significantly younger (36 +/- 7 years vs 64 +/- 13 years) and did not have underlying inflammation either by clinical diagnosis or as reflected in the high normal serum albumin level (> or = 4.0 g/dL). Despite their extreme short bowel syndrome and long exposure to home TPN, ESLD did not develop.

CONCLUSIONS

Approximately 15% of patients who receive prolonged TPN have ESLD with a high rate of morbidity and mortality. The combination of chronic inflammation and the short bowel syndrome appears to be necessary for the development of ESLD with prolonged home TPN.

Medium- and long-chain triacylglycerols in postoperative patients: structured lipids versus a physical mixture

Forty patients, scheduled for abdominal surgery, were randomized to receive postoperatively either a structured or a physical mixture of long-chain triacylglycerols/medium-chain triacylglycerols (LCT/MCT) emulsions to assess the tolerance and the effectiveness of the structured triacylglycerol emulsion. Total parenteral nutrition started the day after surgery and covered 100% of measured energy expenditure with nitrogen (0.2 g N.kg-1.d-1) and non-protein calories: glucose (50%) and lipids (50%). Blood samples for liver function tests, albumin, transthyretin, and triacylglycerols were checked at 0800 h on the day before surgery and on day 1, day 3, and day 6 after surgery. Urine samples were taken each day from day 1 to day 7 for 3-methylhistidine (3 Me His) and total nitrogen measurements. Aspartate transaminase (ASAT), alanine transaminase (ALAT), and triacylglycerol plasma levels in routine clinical biochemistry increased significantly in the physical mixture group. Nitrogen balance and 3 Me His excretion were not significantly different between groups. Structured triacylglycerol (STG) lipid emulsions are as efficacious as the physical mixture on nitrogen balance in postoperative patients. They could have some advantages: no disturbances were found to occur in liver function tests or plasma triacylglycerol levels.

Liver dysfunction and parenteral nutritional therapies

Hepatobiliary dysfunction associated with the use of total parenteral nutrition is a commonly recognized phenomenon occurring in up to 90% of patients on long-term therapy. Reasons for these abnormalities, both supported by research as well as theoretical possibilities are explored. Practical guidelines considered useful in documenting, preventing and treating serious hepatic consequences of total parenteral nutrition are discussed. The role of combined liver and small bowel transplantation as treatment for select patients is also reviewed.

The 1996 Nestlé International Clinical Nutrition Award for Enteral Nutrition. "Enteral versus parenteral nutrition: effects on gastrointestinal function and metabolism": background

Nutrition therapy for the critically ill patient is today an integral part of the treatment concept in intensive care medicine. Parenteral and enteral artificial nutrition are expensive, cost-intensive treatment procedures that are certainly not risk-free. For both ethical and economic reasons, the indications and principles of artificial nutrition must always be adapted to the latest knowledge.

Continuous versus cyclic parenteral nutrition during bonemarrow transplantation: assessment and follow-up

The aim of this prospective, randomized clinical trial was to compare the efficacy of parenteral nutrition (PN) in adult bone marrow transplant (BMT) patients on a continuous (CON) versus a cyclic (CYC) regimen. Twelve patients received CON PN and 12 CYC PN. The groups were homogeneous. CON PN received 27.2 +/- 3.7 kcal/kg/day and for CYC PN 25.9 +/- 4.2 kcal/kg/day (P= 0.45). The duration of PN was 20.4 +/- 7.9 days and 27.3 +/- 13.4 days respectively (P = 0.14). There were no differences between initial and final body weights, either within or between groups. The initial pre-albumin levels were 16.1 +/- 7.5 mg/dl and 20.1 +/- 4.9 mg/dl in CON PN and CYC PN, respectively (P= 0.22), and these were maintained throughout the study. Blood glucose levels did not differ between groups. Measures of liver function were moderately increased, but with no significant differences between groups. There were no significant differences regarding the efficacy of PN or the appearance of complications between CON PN and CYC PN in patients with BMT.

Metabolic pattern and lipid oxidation during abdominal surgery: midazolam versus propofol

Propofol is formulated in an emulsion similar to 10% Intralipid, and several authors have suggested that fat accumulates during its infusion. In this study we used indirect calorimetry to measure lipid metabolism during abdominal surgery in patients anesthetized with propofol, using midazolam as a control. Thirty patients were randomly divided into three groups: Group P (propofol 2 mg/kg + 5 mg.kg-1.h-1, n = 13); Group M (midazolam, n = 9), and Group I (midazolam + 10% Intralipid at rates similar to those infused in Group P, n = 8). They were monitored with an indirect calorimeter for 90 min. Data including oxygen consumption (VO2), CO2 production (VCO2), energy expenditure (EE), respiratory quotient (RQ), and lipid utilization were obtained every 15 min. VO2 increased in all groups at 45 min in respect to basal measurements with no differences between them. VCO2 decreased significantly only in Groups P and I, although no differences between the three groups were observed. EE did not vary in any of the groups. RQ decreased in all groups at 30 min, being significantly higher in Group M than in Groups P and I. Lipid oxidation increased in all groups from the beginning of the study reaching a plateau at 45 min. The lipid oxidation was higher in Groups P and I than in Group M, and coincided (80-100 g/24 h) with the amount of fat administered exogenously (85.4 g/ 24 h for a patient of 70 kg). Compared to VO2, VCO2, and EE, propofol behaves as other anesthetics. The fat administered in its formulation is metabolized in a preferential way, although it is likely that larger doses than those studied in our patients partially accumulate.

The depression of hepatic drug conjugation reactions in rats after lipid-free total parenteral nutrition administered via the portal vein

BACKGROUND

Total parenteral nutrition provides nutrition support in patients who are unable to eat. Long-term parenteral nutrition is accompanied by alterations in gut and liver function including changes in drug metabolism. This study examined the effects of lipid-free total parenteral nutrition in rats on (1) the overall elimination pharmacokinetics of acetaminophen, (2) changes in sulfation and glucuronidation pathways during acetaminophen elimination, and (3) hepatic drug metabolizing enzyme activities determined in vitro.

METHODS

Chronic indwelling catheters were implanted in the aorta, inferior vena cava, and portal vein of adult male Sprague-Dawley rats. Total parenteral nutrition, consisting of 25% dextrose, 5% amino acids, electrolytes, and vitamins, was infused via the portal vein for up to 14 days. Acetaminophen pharmacokinetics were characterized in vivo and selected drug metabolizing enzyme activities were determined in vitro.

RESULTS

Parenteral nutrition for 10 days decreased the total clearance of acetaminophen by 23% (from 11.5 +/- 1.4 to 8.9 +/- 1.4 mL/min per kg; p < .05) and decreased the formation clearance to acetaminophen sulfate (from 6.2 +/- 0.4 to 3.9 +/- 0.5 mL/min per kg; p < .05). Parenteral nutrition decreased microsomal cytochrome P450 concentration (47%), p-nitroanisole demethylase activity (68%) and p-nitrophenol UDP-glucuronosyltransferase activity (58%). Cytosolic glutathione-S-transferase activity towards 1-chloro-2,4-dinitrobenzene decreased 29%. Sulfotransferase activity towards p-nitrophenol and acetaminophen was decreased 48% and 25%, respectively.

CONCLUSION

Lipid-free, total parenteral nutrition depresses drug conjugative metabolism in rats. The magnitude of this effect in humans remains to be investigated.