Preoperative total parenteral nutrition is not associated with mucosal atrophy or bacterial translocation in humans

Use and Misuse of Parenteral Nutrition in Patients with Inflammatory Bowel Disease

Malnutrition is a very common and often underrecognized condition among patients with inflammatory bowel diseases (IBD). This is most commonly due to increased nutritional requirements and gastrointestinal losses, along with reduced oral intake. Screening for malnutrition is an essential component of managing both inpatients and outpatients with IBD. Although enteral nutrition is the preferred route of supplementation, parenteral nutrition (PN) remains an important strategy and should be considered in certain situations, such as cases with short-bowel syndrome, high-output intestinal fistula, prolonged ileus, or small-bowel obstruction. Appropriate use of PN is critical in order to prevent associated complications. This review addresses the common indications for use of PN, the composition of PN, and the possible complications encountered with PN use, as well as scenarios of inappropriate PN use among patients with IBD. A clinical management algorithm for utilizing PN among patients with IBD is proposed in this review.

Mortality and overall and specific infection complication rates in patients who receive parenteral nutrition: systematic review and meta-analysis with trial sequential analysis

BACKGROUND

Parenteral nutrition (PN) is an available option for nutritional therapy and is often required in the hospital setting to overcome malnutrition.

OBJECTIVES

The aim of this study was to assess whether PN is associated with an increased risk of mortality or infectious complications in all groups of hospitalized patients compared with those receiving other nutritional support strategies.

METHODS

For this systematic review and meta-analysis MEDLINE, Embase, Cochrane Central, Scopus, clinicaltrials.gov, and Web of Science were searched for randomized controlled trials (RCTs) and observational studies with parallel groups that explored the effect of PN on mortality and infectious complications, published until March 2021. Two independent reviewers extracted the data and assessed the risk of bias. Fixed-effects meta-analysis was performed to compare the groups from RCTs. Trial sequential analysis (TSA) was used to identify whether the results were sufficient to reach definitive conclusions.

RESULTS

Of the 83 included studies that compared patients receiving PN with those receiving other strategies, 67 RCTs were included in the meta-analysis. PN was not associated with a higher risk of mortality (RR: 1.01; 95% CI: 0.95, 1.07). On the other hand, PN was associated with a higher risk of infectious events (RR: 1.23; 95% CI: 1.12, 1.36). PN was specifically associated with abdominal infection and catheter infection. The TSA showed that there were sufficient data to make numerical conclusions about mortality, any infectious event, and abdominal infectious complications.

CONCLUSIONS

This study suggests that although PN is not associated with greater mortality in hospitalized patients, it is associated with infectious complications. Through TSA, definite conclusions about survival and infection rates could be made.This review was registered at www.crd.york.ac.uk/prospero/ as CRD42018075599.

The Effect of Hyperglycemic Hyperinsulinemia on Small-Intestinal Mucosal Protein Synthesis in Patients After Surgical Stress

Hyperglycemic hyperinsulinemia cannot stimulate intestinal protein synthesis in healthy individuals but does so in conditions characterized by an altered somatotropic axis such as diabetes. Only in a state of growth hormone resistance (high growth hormone but low insulin like growth factor [IGF-1] concentrations), extra insulin may acutely reverse the impaired, growth-hormone-induced IGF-1 release, thereby exerting anabolic actions at the intestinal tract. Growth hormone resistance can be also found in patients after surgical stress. Therefore, we wanted to test the hypothesis whether hyperglycemic hyperinsulinemia would stimulate ileal protein synthesis in the latter condition. Mass spectrometry techniques (capillary gas chromatography/combustion isotope ratio mass spectrometry) were used to directly determine the incorporation rate of 1-[(13)C]-leucine into ileal mucosal protein. All subjects had an ileostomy, which allowed easy access to the ileal mucosa, and consecutive sampling from the same tissue was performed during continuous isotope infusion (0.16 mumol/kg min). Isotopic enrichments and fractional protein synthesis were determined at baseline (period I) and after a 4-hour glucose infusion (170 mg/kg/h) or after infusion of saline (control group) (period II). In controls, ileal protein synthesis declined significantly during prolonged isotope infusion (period I: 1.11 +/- 0.14%/h, period II: 0.39 +/- 0.13%/h, p < .01). In contrast, ileal protein synthesis remained constant during glucose infusion (period I: 1.32 +/- 0.35%/h, period II: 1.33 +/- 0.21%/h, n.s. vs period I, but p < .005 vs the corresponding value at the end of period II in the control group). Using the continuous tracer infusion technique, ileal protein synthesis seemingly declines over a short time in control subjects. We found evidence that this artificial decline was due to mass effects of a rapidly turning over mucosa protein pool in which an isotopic plateau was reached during the experiment and of which the size amounted to approximately 4% of the total mixed protein pool. Maintenance of ileal protein synthesis during glucose infusion therefore indicates a rise of ileal protein synthesis in a slowly turning over protein pool. This effect in postsurgical patients would be compatible with the concept of intestinal insulin action to depend on the specific clinical state (eg, growth hormone resistance).

Animal models of gastrointestinal and liver diseases. Animal models of infant short bowel syndrome: translational relevance and challenges

Intestinal failure (IF), due to short bowel syndrome (SBS), results from surgical resection of a major portion of the intestine, leading to reduced nutrient absorption and need for parenteral nutrition (PN). The incidence is highest in infants and relates to preterm birth, necrotizing enterocolitis, atresia, gastroschisis, volvulus, and aganglionosis. Patient outcomes have improved, but there is a need to develop new therapies for SBS and to understand intestinal adaptation after different diseases, resection types, and nutritional and pharmacological interventions. Animal studies are needed to carefully evaluate the cellular mechanisms, safety, and translational relevance of new procedures. Distal intestinal resection, without a functioning colon, results in the most severe complications and adaptation may depend on the age at resection (preterm, term, young, adult). Clinically relevant therapies have recently been suggested from studies in preterm and term PN-dependent SBS piglets, with or without a functional colon. Studies in rats and mice have specifically addressed the fundamental physiological processes underlying adaptation at the cellular level, such as regulation of mucosal proliferation, apoptosis, transport, and digestive enzyme expression, and easily allow exogenous or genetic manipulation of growth factors and their receptors (e.g., glucagon-like peptide 2, growth hormone, insulin-like growth factor 1, epidermal growth factor, keratinocyte growth factor). The greater size of rats, and especially young pigs, is an advantage for testing surgical procedures and nutritional interventions (e.g., PN, milk diets, long-/short-chain lipids, pre- and probiotics). Conversely, newborn pigs (preterm or term) and weanling rats provide better insights into the developmental aspects of treatment for SBS in infants owing to their immature intestines. The review shows that a balance among practical, economical, experimental, and ethical constraints will determine the choice of SBS model for each clinical or basic research question.

Feeding the gut: how, when and with what -- the metabolic issue

PURPOSE OF REVIEW

To review the literature on feeding critically ill patients with special emphasis on the intestine.

RECENT FINDINGS

Many dogmas have been questioned in the past few years. In particular, the absence of evidence for impact on outcomes in critically ill patients has been highlighted. So 'early enteral feeding', the trophic effect on intestinal mucosa in humans, 'pharmaco-nutrition', postpyloric feeding and prokinetic drugs have all been found to lack proper evidence to affect outcomes.

SUMMARY

The use of gastric feeding in critical illness is recommended. Successful gastric feeding is indicative of a functional gastrointestinal tract. Pharmacological effects of nutrients are questionable, but supplementation of deficits (glutamine, selenium, etc.) may be in the patient's best interest. A more individualized prescription of nutrition in the critically ill is advocated.

Intestinal microbial diversity and perioperative complications

BACKGROUND AND AIMS

Enteral nutrient deprivation via parenteral nutrition (PN) in a mouse model leads to a local mucosal inflammatory response. This proinflammatory response leads to a loss of epithelial barrier function and atrophy of the intestine. Although the underlying mechanisms are unknown, a potential contributing factor is the impact PN has on the intestinal microbiome. We recently identified a shift in the intestinal microbial community in mice given PN; however, it is unknown whether such changes occur in humans. We hypothesized that similar microbial changes occur in humans during periods of enteral nutrient deprivation.

METHODS

A series of small bowel specimens were obtained from pediatric and adult patients undergoing small intestinal resection. Mucosally associated bacteria were harvested and analyzed using 454 pyrosequencing techniques. Statistical analysis of microbial diversity and differences in microbial characteristics were assessed between enterally fed and enterally deprived portions of the intestine. Occurrence of postoperative infectious and anastomotic complications was also examined.

RESULTS

Pyrosequencing demonstrated a wide variability in microbial diversity within all groups. Principal coordinate analysis demonstrated only a partial stratification of microbial communities between fed and enterally deprived groups. Interestingly, a tight correlation was identified in patients who had a low level of enteric microbial diversity and those who developed postoperative enteric-derived infections or intestinal anastomotic disruption.

CONCLUSIONS

Loss of enteral nutrients and systemic antibiotic therapy in humans is associated with a significant loss of microbial biodiversity within the small bowel mucosa. These changes were associated with a number of enteric-derived intestinal infections and intestinal anastomotic disruptions.

Complications and monitoring - Guidelines on Parenteral Nutrition, Chapter 11

Compared to enteral or hypocaloric oral nutrition, the use of PN (parenteral nutrition) is not associated with increased mortality, overall frequency of complications, or longer length of hospital stay (LOS). The risk of PN complications (e.g. refeeding-syndrome, hyperglycaemia, bone demineralisation, catheter infections) can be minimised by carefully monitoring patients and the use of nutrition support teams particularly during long-term PN. Occuring complications are e.g. the refeeding-syndrome in patients suffering from severe malnutrition with the initiation of refeeding or metabolic, hypertriglyceridemia, hyperglycaemia, osteomalacia and osteoporosis, and hepatic complications including fatty liver, non-alcoholic fatty liver disease, cholestasis, cholecystitis, and cholelithiasis. Efficient monitoring in all types of PN can result in reduced PN-associated complications and reduced costs. Water and electrolyte balance, blood sugar, and cardiovascular function should regularly be monitored during PN. Regular checks of serum electrolytes and triglycerides as well as additional monitoring measures are necessary in patients with altered renal function, electrolyte-free substrate intake, lipid infusions, and in intensive care patients. The metabolic monitoring of patients under long-term PN should be carried out according to standardised procedures. Monitoring metabolic determinants of bone metabolism is particularly important in patients receiving long-term PN. Markers of intermediary, electrolyte and trace element metabolism require regular checks.

Organisation, regulations, preparation and logistics of parenteral nutrition in hospitals and homes; the role of the nutrition support team - Guidelines on Parenteral Nutrition, Chapter 8

PN (parenteral nutrition) should be standardised to ensure quality and to reduce complications, and it should be carried out in consultation with a specialised nutrition support team whenever possible. Interdisciplinary nutrition support teams should be established in all hospitals because effectiveness and efficiency in the implementation of PN are increased. The tasks of the team include improvements of quality of care as well as enhancing the benefit to cost ratio. Therapeutic decisions must be taken by attending physicians, who should collaborate with the nutrition support team. “All-in-One” bags are generally preferred for PN in hospitals and may be industrially manufactured, industrially manufactured with the necessity to add micronutrients, or be prepared “on-demand” within or outside the hospital according to a standardised or individual composition and under consideration of sterile and aseptic conditions. A standardised procedure should be established for introduction and advancement of enteral or oral nutrition. Home PN may be indicated if the expected duration of when PN exceeds 4 weeks. Home PN is a well established method for providing long-term PN, which should be indicated by the attending physician and be reviewed by the nutrition support team. The care of home PN patients should be standardised whenever possible. The indication for home PN should be regularly reviewed during the course of PN.

Peptide YY induces intestinal proliferation in peptide YY knockout mice with total enteral nutrition after massive small bowel resection

OBJECTIVE

In previous research, peptide YY (PYY) administered in supraphysiological doses did not induce significant proliferative effects in rats that were allowed to feed ad libitum after massive small bowel resection (SBR). The main reason may well have been the interference of endogenous PYY released from L cells in the distal bowel in response to the presence of augmented unabsorbed intraluminal nutrients. The purpose of the present study was to explore the effect of PYY on intestinal proliferation with total enteral nutrition (TEN) in a SBR model of PYY knockout (Pyy(-/-)) mice, which do not produce endogenous PYY.

MATERIALS AND METHODS

Pyy(-/-) mice were assigned into 3 experimental groups: sham mice (sham group) underwent bowel transection and reanastomosis, and received TEN; SBR mice (SBR group) underwent a 50% small bowel resection, and received TEN; and SBR-PYY mice (SBR-PYY group) underwent a 50% small bowel resection, received TEN, and were treated with PYY1-36 subcutaneously from day 2 postoperatively. Parameters of enterocyte proliferation and apoptosis were determined on day 8 following operation.

RESULTS

SBR-PYY mice demonstrated a significant increase in (vs SBR) bowel and mucosal weights, mucosal DNA and protein, villus height, and crypt depth in jejunum and ileum. SBR-PYY mice also showed an increased crypt cell proliferation index in jejunum and ileum and decreased villus cell apoptotic index in ileum compared with SBR animals.

CONCLUSIONS

In an SBR model of Pyy(-/-) mice, PYY induces proliferation of residual intestine with TEN.

Food fight! Parenteral nutrition, enteral stimulation and gut-derived mucosal immunity

INTRODUCTION

Nutrition support is an integral component of modern patient care. Type and route of nutritional support impacts clinical infectious outcomes in critically injured patients.

DISCUSSION

This article reviews the relationships between type and route of nutrition and gut-derived mucosal immunity in both the clinical and laboratory settings.

Enteral versus parenteral nutrition after gastrointestinal surgery: a systematic review and meta-analysis of randomized controlled trials in the English literature

BACKGROUND

Although previous studies recommend the use of enteral nutrition (EN), the benefit of EN after elective gastrointestinal surgery has not been comprehensively demonstrated as through a meta-analysis. Our aim is to determine whether enteral nutrition is more beneficial than parenteral nutrition.

METHODS

A search was conducted on Medline, Web of Science, the Cochrane Library electronic databases, and bibliographic reviews. The trials were based on randomization, gastrointestinal surgery, and the reporting of at least one of the following end points: any complication, any infectious complication, mortality, wound infection and dehiscence, anastomotic leak, intraabdominal abscess, pneumonia, respiratory failure, urinary tract infection, renal failure, any adverse effect, and duration of hospital stay.

RESULTS

Twenty-nine trials, which included 2,552 patients, met the criteria. EN was beneficial in the reduction of any complication (relative risk (RR), 0.85; 95% confidence interval (CI), 0.74-0.99; P = 0.04), any infectious complication (RR, 0.69; 95% CI, 0.56-0.86; P = 0.001), anastomotic leak (RR, 0.67; 95% CI, 0.47-0.95; P = 0.03), intraabdominal abscess (RR, 0.63; 95% CI, 0.41-0.95; P = 0.03), and duration of hospital stay (weighted mean difference, -0.81; 95% CI, -1.25-0.38; P = 0.02). There were no clear benefits in any of the other complications.

CONCLUSION

The present findings would lead us to recommend the use of EN rather than PN when possible and indicated.

A Review of Surgical Nutrition

Malnutrition remains a common problem in surgical patients and is associated with significant morbidity and mortality. It is imperative that all surgical patients undergo nutritional screening on admission to highlight malnourished or at risk patients and implement a nutritional plan. Nutrition can be delivered by oral supplements, enteral or parenteral feeding, the route depending on an individual's requirements and surgical condition. Enteral feeding has largely been regarded as superior to parenteral feeding, as it is cheaper, safer and “more physiological” but studies show this is not always the case. This article reviews the basics of surgical nutrition and assesses the evidence supporting enteral versus parenteral nutrition.

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.

Enteral nutrition versus parenteral nutrition--the risks and benefits

The role of nutrition in patient care became a part of mainstream medicine at about the end of the 1960s, with the publication of several papers that showed a benefit of nutritional support in the prevention of complications. At that time, the emphasis was on nutrition given by the parenteral route. Since then, a series of studies that compared parenteral nutrition with enteral nutrition have suggested that the enteral route of feeding causes fewer complications than the parenteral route. A careful review of the data shows that nutritional support can increase the risk of complications when given to well-nourished, obese and hyperglycemic patients. The avoidance of overfeeding and hyperglycemia is, therefore, of paramount importance. In this context, enteral nutrition, for which gastrointestinal tolerance limits overfeeding, can protect the patient.

Review article: bacterial translocation in the critically ill--evidence and methods of prevention

BACKGROUND

Delayed sepsis, systemic inflammatory response syndrome (SIRS) and multiorgan failure remain major causes of morbidity and mortality on intensive care units. One factor thought to be important in the aetiology of SIRS is failure of the intestinal barrier resulting in bacterial translocation and subsequent sepsis.

AIM

This review summarizes the current knowledge about bacterial translocation and methods to prevent it.

METHODS

Relevant studies during 1966-2006 were identified from a literature search. Factors, which detrimentally affect intestinal barrier function, are discussed, as are methods that may attenuate bacterial translocation in the critically ill patient.

RESULTS

Methodological problems in confirming bacterial translocation have restricted investigations to patients undergoing laparotomy. There are only limited data available relating to specific interventions that might preserve intestinal barrier function or limit bacterial translocation in the intensive care setting. These can be categorized broadly into pre-epithelial, epithelial and post-epithelial interventions.

CONCLUSIONS

A better understanding of factors that influence translocation could result in the implementation of interventions which contribute to improved patient outcomes. Glutamine supplementation, targeted nutritional intervention, maintaining splanchnic flow, the judicious use of antibiotics and directed selective gut decontamination regimens hold some promise of limiting bacterial translocation. Further research is required.

Specific topics and complications of parenteral nutrition

BACKGROUND/AIMS

Total parenteral nutrition (TPN) has proven a tremendous advance in all disciplines in medicine but itself introduces a spectrum of possible complications related to both the parenteral nutritional solution as well as the technique of intravenous delivery. Our aim is to review the specific complications of TPN.

MATERIALS AND METHODS

This article presents a critical literature review of relevant topics in TPN-related complications-metabolic, infections, and nutrition related.

RESULTS

Special emphasis focuses on complications of TPN arising from thrombosis or infectious sequelae related to the central venous catheterization and metabolic complications involving the kidneys, bones, liver, and biliary tract.

CONCLUSIONS

Awareness and surveillance of TPN-related complications can prevent, potentially, some of these complications related to parenteral nutritional support.

Risks and benefits of nutritional support during critical illness

Critically ill patients who depend on intensive care for more than a few days reveal profound erosion of lean body mass, which is thought to contribute to high morbidity and mortality. Despite a shortfall of evidence that supplemental feeding actually alters clinical outcome of these life-threatening disease states, this observation evoked an almost universal, albeit often inappropriate, use of nutritional support (NS) in the critically ill, administered via the parenteral or the enteral route. Lack of knowledge and overenthusiasm subsequently resulted in complications associated with both parenteral nutrition (PN) and enteral nutrition (EN), which led to the standing controversy over which should be preferred. With time, however, it became clear that EN and PN are not mutually exclusive and that critically ill patients requiring NS should be fed according to the functional status of the gastrointestinal tract. In addition, tight blood glucose control with insulin is advised in fed critically ill patients because overall metabolic control appears to surpass any outcome benefit attributed to the route of feeding. Recently, various special nutritional formulas have been suggested to prevent or treat multiorgan failure in the critically ill, among other pathways via modulation of immune function. Although special nutritional formulas may be promising in a variety of clinical settings, based on currently available data, these cannot be recommended for routine use in critically ill patients.

Nutrition and management of enterocutaneous fistula

BACKGROUND

The management of enterocutaneous fistula is challenging, with significant associated morbidity and mortality. This article reviews treatment, with emphasis on the provision and optimal route of nutritional support.

METHODS

Relevant articles were identified using Medline searches. Secondary articles were identified from the reference lists of key papers.

RESULTS AND CONCLUSION

Management of enterocutaneous fistula should initially concentrate on correction of fluid and electrolyte imbalances, drainage of collections, treatment of sepsis and control of fistula output. The routine use of somatostatin infusion and somatostatin analogues remains controversial; although there are data suggesting reduced time to fistula closure, there is little evidence of increased probability of spontaneous closure. Malnutrition is common and adequate nutritional provision is essential, enteral where possible, although supplemental parenteral nutrition is often required for high-output small bowel fistulas. The role of immunonutrition is unknown. Surgical repair should be attempted when spontaneous fistula closure does not occur, but it should be delayed for at least 3 months.

Total parenteral nutrition-related gastroenterological complications

Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review.

Glutamine: do the data support the cause for glutamine supplementation in humans?

This review examines the preclinical rationale for using glutamine supplements and reviews the prospective randomized trials using glutamine to improve outcomes in patients. A special role for glutamine in gut physiology and in management of a variety of serious illnesses has been suggested, because it is the most abundant extracellular amino acid, and is used at high rates by the gut, liver, central nervous system, and immune cells. A state of relative Gln deficiency has been postulated in humans based on the decrease in plasma Gln in acute critical illness, but the decrease in plasma Gln is not specific for that amino acid, predicts only poorer outcome, and has not been validated to identify a deficiency state. Current evidence does not necessarily predict a special need or role for Gln in critical illness. Clinical efficacy of supplemental Gln has been difficult to demonstrate, possibly related to the lack of a Gln deficiency state, the wide range of end points used that reflect the lack of certainty of the predicted effect of supplementation, the heterogeneous patient populations studied, the lack of stable clinical course during the study, the lack of adequate power, and the relatively short follow-up period. Prospective randomized clinical trials of Gln supplementation were reviewed in patients with short-bowel syndrome, during cancer chemotherapy and in bone marrow transplantation, and in surgical, burn, and intensive care unit patients. No firm recommendation can be made at this time. Future studies should seek to develop a more standard and stable design for intervention in sufficiently powered studies.

Intestinal failure-associated liver disease: what do we know today?

Intestinal failure-associated liver disease develops in 40% to 60% of infants who require long-term total parenteral nutrition (TPN) for intestinal failure and 15% to 40% of adults on home parenteral nutrition. The clinical spectrum includes hepatic steatosis, cholestasis, cholelithiasis, and hepatic fibrosis. Progression to biliary cirrhosis and the development of portal hypertension and liver failure occurs in a minority but is more common in infants and neonates than in adults. The pathogenesis is multifactorial. In infants it is related to prematurity, low birth weight, duration of PN, short bowel syndrome requiring multiple laparotomies, and recurrent sepsis. Other important mechanisms include lack of enteral feeding, which leads to reduced gut hormone secretion; reduction of bile flow and biliary stasis, which leads to the development of cholestasis; and biliary sludge and gallstones, which exacerbate hepatic dysfunction. In adults, IFALD is less common and related to age, length of time on PN, total caloric intake, and lipid or glucose overload. In preterm infants, a deficiency of taurine or cysteine may play a role, whereas in both adults and children, choline deficiency may exacerbate IFALD. Lipid emulsions, choline deficiency, and manganese toxicity are associated with both hepatic steatosis and cholestasis in adults and children. Management strategies for the prevention of intestinal failure-induced liver disease include early enteral feeding, a multidisciplinary approach to the management of parenteral nutrition, and aseptic catheter techniques to reduce sepsis. The addition of choline, taurine, and cysteine to PN solutions may also play a role. Oral administration of ursodeoxycholic acid may improve bile flow and reduce gallbladder stasis. Survival after either isolated small bowel or combined liver and small bowel transplantation is approximately 50% at 5 years, making this an acceptable therapeutic option in adults and children with irreversible liver and intestinal failure.

Bacterial translocation studied in 927 patients over 13 years

BACKGROUND

Bacterial translocation (BT) describes the passage of bacteria from the gastrointestinal tract to normally sterile tissues such as the mesenteric lymph nodes (MLNs) and other internal organs. The clinical and pathophysiological significance of BT remains controversial. This report describes results obtained over a 13-year period of study.

METHODS

MLNs were obtained from 927 patients undergoing laparotomy. Nasogastric aspirates were obtained from 458 (49.4 per cent) of 927 patients for culture; pH was measured in 172 (37.6 per cent) of 458. Preoperative clinical variables were evaluated and factors that influenced BT were included in a multivariate logistic regression analysis.

RESULTS

BT was identified in 130 (14.0 per cent) of 927 patients. Postoperative sepsis was more common in patients with BT (42.3 versus 19.9 per cent; P < 0.001). Independent preoperative variables associated with BT were emergency surgery (P = 0.001) and total parenteral nutrition (TPN) (P = 0.015). Gastric colonization was confirmed in 248 (54.1 per cent) of 458 patients, and was associated with both BT (P = 0.015) and postoperative sepsis (P = 0.029). A gastric pH of less than 4 was associated with a significant reduction in gastric colonization (53 versus 80 per cent; P < 0.001) and postoperative sepsis (46 versus 70.3 per cent; P = 0.018) but not BT.

CONCLUSION

BT is associated with postoperative sepsis. Emergency surgery and TPN are independently associated with an increased prevalence of BT.

Effects of total parenteral nutrition on rat enteric nervous system, intestinal morphology, and motility

Total parenteral nutrition (TPN) is often crucial for patients not being able to feed enterally or having intestinal absorptive deficits. Enteral nutrition is, however, frequently regarded vital for maintaining functional and structural intestinal integrity. The aim of this study was to investigate possible effects of TPN on rat distal small intestine compared to enterally fed identically housed controls, regarding the enteric nervous system (ENS), motility in vitro, and morphology. This study shows that motor responses evoked by electrical stimulation or exposure to vasoactive intestinal peptide (VIP), pituitary adenylate cyclase activating peptide-27 (PACAP-27), and nitric oxide (NO) donor were unchanged. By using immunohistochemistry, the numbers of submucous (P < 0.05) and myenteric (P < 0.05) nerve cells were found to increase, expressed as numbers per unit length. The percentage of neurons expressing VIP, PACAP-27, NO-synthase, and galanin remained unchanged, however. By in situ hybridization the number of submucous neurons expressing neuropeptide Y-mRNA was found to decrease (P < 0.05); the other populations were unaltered. Morphometry revealed an increased submucosal thickness (P < 0.05), while intestinal circumference markedly decreased (P < 0.0001) in TPN-treated rats. In conclusion, TPN treatment resulted in reduced intestinal circumference leading to condensation of enteric neurons. No marked changes in neurotransmitter expression of the enteric neurons or in motor activity were noted.

The effects of long-term total parenteral nutrition on gut mucosal immunity in children with short bowel syndrome: a systematic review

BACKGROUND: Short bowel syndrome (SBS) is defined as the malabsorptive state that often follows massive resection of the small intestine. Most cases originate in the newborn period and result from congenital anomalies. It is associated with a high morbidity, is potentially lethal and often requires months, sometimes years, in the hospital and home on total parenteral nutrition (TPN). Long-term survival without parenteral nutrition depends upon establishing enteral nutrition and the process of intestinal adaptation through which the remaining small bowel gradually increases its absorptive capacity. The purpose of this article is to perform a descriptive systematic review of the published articles on the effects of TPN on the intestinal immune system investigating whether long-term TPN induces bacterial translocation, decreases secretory immunoglobulin A (S-IgA), impairs intestinal immunity, and changes mucosal architecture in children with SBS. METHODS: The databases of OVID, such as MEDLINE and CINAHL, Cochran Library, and Evidence-Based Medicine were searched for articles published from 1990 to 2001. Search terms were total parenteral nutrition, children, bacterial translocation, small bowel syndrome, short gut syndrome, intestinal immunity, gut permeability, sepsis, hyperglycemia, immunonutrition, glutamine, enteral tube feeding, and systematic reviews. The goal was to include all clinical studies conducted in children directly addressing the effects of TPN on gut immunity. RESULTS: A total of 13 studies were identified. These 13 studies included a total of 414 infants and children between the ages approximately 4 months to 17 years old, and 16 healthy adults as controls; and they varied in design and were conducted in several disciplines. The results were integrated into common themes. Five themes were identified: 1) sepsis, 2) impaired immune functions: In vitro studies, 3) mortality, 4) villous atrophy, 5) duration of dependency on TPN after bowel resection. CONCLUSION: Based on this exhaustive literature review, there is no direct evidence suggesting that TPN promotes bacterial overgrowth, impairs neutrophil functions, inhibits blood's bactericidal effect, causes villous atrophy, or causes to death in human model.The hypothesis relating negative effects of TPN on gut immunity remains attractive, but unproven. Enteral nutrition is cheaper, but no safer than TPN. Based on the current evidence, TPN seems to be safe and a life saving solution.

Atrofia mucosa/translocação bacteriana na sepse experimental em ratos Wistar

OBJETIVO: Avalizar a relação entre lesão mucosa e translocação bacteriana. MÉTODO: Utilizou-se 50 ratos distribuídos em 5 grupos: 1.Controle: injeção de inóculo padrão de Pseudomonas aeruginosa, 2.Dreno: injeção do inóculo padrão e drenagem da cavidade abdominal, após 6 horas, 3.Lavado: injeção do inóculo padrão e lavagem da cavidade abdominal, após 6 horas, 4.Lavado + dreno: injeção do inóculo padrão e após 6 horas, drenagem e lavagem da cavidade, 5.Normal: avaliação histológica da parede intestinal normal. Após o óbito, realizou-se hemocultura e cultura peritoneal. Realizou-se medida da espessura total da parede do jejuno e da camada mucosa em vilosidades seccionadas de forma longitudinal. RESULTADOS: Na hemocultura, houve crescimento de Pseudomonas aeruginosa e Escherichia coli em 90% e 52,5% dos animais. Na cultura peritoneal, houve crescimento de P. aeruginosa, E. coli e Klebsiella sp em 87,5%, 85% e 5% dos animais. Quanto a altura da camada mucosa e da parede intestinal, não houve alteração estatisticamente significativa entre os 5 grupos. CONCLUSÃO: A sepse aguda não causou alteração na camada mucosa do intestino delgado e a translocação ocorrida não pode ser considerada como decorrente de uma lesão da mucosa intestinal.

A review of the trends in the use of enteral and parenteral nutrition support

This is a review article that discusses the trends in the use of enteral and parenteral nutrition support. Although enteral nutrition has existed longer than parenteral nutrition, only recent data would suggest a clinical benefit of enteral nutrition compared with parenteral nutrition. In this article, indications for parenteral nutrition are listed. Also, data comparing bacterial translocation and complications associated with both forms of nutritional support are discussed. Clinical outcome in specific gastrointestinal diseases is also discussed.

Alterações da mucosa intestinal em ratos: estudo morfométrico em três diferentes tratamentos após indução experimental de sepse abdominal aguda

OBJETIVO: Verificar as possíveis alterações morfológicas da parede intestinal provocadas pela contaminação de uma monocultura bacteriana na cavidade abdominal de ratos, após tratamento por drenagem, lavagem e a combinação destes dois processos. MÉTODOS: Foram utilizados 50 ratos fêmeas da linhagem Wistar, foram distribuídos em 5 subgrupos: grupo Controle (C) - recebeu um inóculo padrão com 1,2.10(9) de Pseudomonas aeruginosa, intraperitonial, sem nenhum tipo de tratamento; grupo Dreno (D) - inóculo padrão e realizada a drenagem da cavidade abdominal; grupo Lavado (L) - inóculo e realizada a lavagem da cavidade abdominal com solução salina; grupo L+D - inóculo e submetido aos dois tipos de tratamentos; grupo Normal (N) sem nenhum tipo de inoculação ou tratamento. Realizou-se a análise morfométrica das lâminas coradas por H.E da mucosa intestinal e hemocultura. RESULTADOS: Não houve diferenças estatisticamente significantes na espessura da mucosa intestinal entre os 5 subgrupos de ratos analisados no período de 24 horas após a injeção do inóculo. 37 animais que receberam o inóculo evoluíram para o óbtito entre 5,83 e 28 horas, com 2 animais do grupo L sobrevivendo por um período de 28 horas. CONCLUSÃO: A sepse aguda não causou alterações morfológicas mensuráveis através desta metodologia na parede intestinal.

Enteral feeding and gut atrophy

PURPOSE OF REVIEW

Because of the hypothesis that enteral feeding prevents intestinal mucosal atrophy and bacterial translocation, when fasting or malnutrition is present, nutrition support by the enteral route is usually preferred, if it is available. If nutrients are provided only parenterally intestinal mucosal mass falls dramatically in rats, but the relevance of this finding to humans has not been documented. This article reviews findings in the last 2 years relating to this dilemma.

RECENT FINDINGS

Most work continues to be done in rats and pigs, two species that demonstrate mucosal atrophy with fasting. The earlier demonstration of effects of administration of hormones and glutamine have been corroborated, but proper controls for hormones (related peptides) or glutamine (most importantly glutamate) have usually not been included. In humans mucosal atrophy does not occur except modestly (approximately 10% decrease in thickness) in some reports during catabolic conditions, such as in critical-care units. Even so, no evidence for reversal by enteral feeding has as yet been provided. On the other hand, evidence for specific gene adaptation with or without mucosal atrophy has begun to appear in animals and humans.

SUMMARY

The focus on mucosal atrophy has obscured the adaptation that may occur simultaneously to minimize the atrophy. Attention to gene adaptation during fasting and malnutrition may provide evidence, in future, for appropriate therapeutic interventions.

Bacterial translocation: clinical implications and prevention

The occurrence of BT has been well documented in experimental animal models of hemorrhagic shock, trauma, severe burns, cirrhosis, pancreatitis, and bacterial overgrowth. Translocation of viable bacteria and endotoxins into mesenteric lymph nodes and other gut-associated lymphatic tissue is thought to activate a complex interplay of mediators that initiates the SIRS. Multiple humoral and cellular systems cause synthesis, expression, and release of inflammatory mediators, such as toxic oxygen radicals, proteolytic enzymes, adherence molecules, and various cytokines. A massive sustained proinflammatory response can ultimately result in irreversible multiple organ dysfunction. Because BT is associated with splanchnic hypoperfusion, the cornerstone of therapy involves rapid resuscitation and restoration of tissue perfusion. If a septic focus can be identified, it should be removed. Gut protectants, promotility agents, antioxidants, and immune-enhancing diets have shown promise in improving length of survival in these critically ill patients.

Bacterial translocation: effects of artificial feeding

The most striking observation when reviewing recent literature in the field of bacterial translocation in the intestine is the small number of publications involving human subjects. Although there are some excellent reviews in this field published during the last 2 years, all experimental contributions come from animal experiments. It is therefore crucial to evaluate how valid the animal models are for human pathophysiology. Studies focusing on translocation as a major pathogenic mechanism are urgently needed to help clinicians to make correct decisions concerning protection of the gut and decide upon nutrition in the intensive care unit.

Elemental and intravenous total parenteral nutrition diet-induced gut barrier failure is intestinal site specific and can be prevented by feeding nonfermentable fiber

OBJECTIVE

Parenteral nutrition and elemental diets both cause bacterial translocation, immune dysfunction, and increased infection in laboratory animals, whereas elemental diets, with or without fiber, ameliorate some, but not all gut barrier failure. The purpose of this study is to investigate, in an Ussing chamber system, whether elemental vs. parenteral diets induce gut barrier failure in specific anatomical sites in the intestine and whether fiber can ameliorate this phenomenon.

DESIGN

Controlled study in laboratory animals.

SETTING

University laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Nutritional support was provided to rats for 7 days by oral total parenteral nutrition (TPN; elemental diet) 307 kcal/kg/day, intravenous TPN (parenteral diet) 307 kcal/kg/day via jugular venous catheters, or rodent chow (controls).

MEASUREMENTS AND MAIN RESULTS

Permeability to bacteria in intestinal segments of ileum, jejunum, and colon was evaluated in an Ussing chamber. Results were correlated with bacterial translocation to the mesenteric lymph nodes. Intravenous TPN caused greater bacterial translocation in all small intestinal segments and the cecum when compared with chow (p <.05). Oral TPN caused gut barrier failure only in the ileal segment, but not in the remainder of the small intestine (p <.001). Addition of cellulose provided a greater protection of the ileum to permeability than did pectin (p <.01).

CONCLUSIONS

TPN causes global intestinal barrier failure, but elemental diet prevents barrier failure in parts of the small intestine other than the ileum. The addition of cellulose fiber to elemental diet can ameliorate further barrier failure in the ileum.

The gastrointestinal tract in critical illness

The gut has often been suggested to be one of the essential factors in the pathogenesis of many nosocomial infections and possibly multi-organ failure. In the light of several recent studies, the importance of normal gut bacterial flora and the role of the gastrointestinal tract in human immune function are now better understood. It now seems clear that stimulation of gut-associated lymphoid tissue through enteral feeding is the key to the preservation of mucosal-derived immunity; however, the role of this native gastrointestinal immune function in the subsequent development of sepsis and multi-organ dysfunction syndrome remains the subject of ongoing study.

Total parenteral nutrition: potion or poison?

The role of nutritional support in clinical care has burgeoned over the past 40 y. Initially, total parenteral nutri-tion (TPN) was considered to be the standard of care. Later, the concept that enteral nutrition (EN) promoted gut function and prevented the translocation of intestinal bacteria resulted in EN becoming the standard of care. Furthermore, TPN was consid-ered to be a dangerous form of therapy. Critical review of the data suggests that, in humans, TPN does not cause mucosal atrophy or increase bacterial translocation. Increased sepsis with TPN can be ascribed to overfeeding; the dangers of TPN-induced complications have been exaggerated. TPN is an equally effective alternative to EN when a risk of malnutrition is present and EN is not tolerated or when gut failure is present.

Enteral and parenteral nutrition: evidence-based approach

Nutrition support for patients in hospital has become an essential form of therapy. Total parenteral nutrition (TPN) was the preferred way of giving nutrition to hospital patients for many years but enteral nutrition (EN) is now the preferred route. EN is believed to promote gut function and prevent translocation of intestinal bacteria, thus reducing the incidence of sepsis in critically ill patients. In consequence, the use of TPN has been discouraged as a dangerous form of therapy. Critical review of the data suggests that in the human subject TPN does not cause mucosal atrophy or increase translocation of bacteria through the small intestine. However, overfeeding, which is easy with TPN, can explain the results of studies which have shown that TPN increases sepsis. Furthermore, the risks of TPN-induced complications have been exaggerated. When there is risk of malnutrition and EN is not tolerated, or there is gut failure, TPN is an equally effective and safe alternative.

Complications of long-term home total parenteral nutrition: their identification, prevention and treatment

The purpose of this review is to describe the most common complications of home total parenteral nutrition, their identification, treatment and prevention. Data sources were manuscripts and abstracts published in the English literature since 1968. Studies were selected for summarization in this review on the basis of clinical relevance to the practicing clinician. Home total parenteral nutrition is a relatively safe, life-saving method for nutrient delivery in patients with compromised gastrointestinal function. However, numerous complications, with associated morbidity and mortality, involving the delivery system and the gastrointestinal, renal, and skeletal systems may develop. Catheter-related complications are often preventable and treatable when they occur, although renal and bone abnormalities have elusive etiologies.

Enteral versus parenteral nutrition: a pragmatic study

Controversy persists as to the optimal means of providing adjuvant nutritional support. The aim of this study was to compare enteral nutrition (EN) and parenteral nutrition (TPN) in terms of adequacy of nutritional intake, septic and nonseptic morbidity, and mortality. This was a prospective pragmatic study, whereby the route of delivery of nutritional support was determined by the attending clinician's assessment of gastrointestinal function. Patients considered to have inadequate gastrointestinal function were given TPN (group 1), while those deemed to have a functioning gastrointestinal tract received EN (group 2). Patients in whom there was reasonable doubt as to the adequacy of intestinal function were randomized to receive either TPN (group 3) or EN (group 4). The trial setting was a large district general hospital with a dedicated nutrition team. A total of 562 patients were included in the study (331 males; median age 67 y). Gastrointestinal function on entry into the study was considered inadequate in 267 patients who were given TPN (group 1) and adequate in 231 whom received EN (group 2). There was clinical uncertainty about the adequacy of gut function in 64 patients (11.4%) who were randomized to receive either TPN (group 3, 32 patients) or EN (group 4, 32 patients). The incidence of inadequate nutritional intake was significantly higher in group 4 compared with group 3 (78.1% versus 25%, P < 0.001). Complications related to the delivery system and other feed-related morbidity were significantly more frequent in both EN groups compared with the respective TPN groups. EN was associated with a higher overall mortality in both nonrandomized and randomized patients. There were no significant differences observed in the incidences of septic morbidity between patients receiving TPN and those given EN. EN is associated with a higher incidence of inadequate nutritional intake, complications related to the delivery system, and other feed-related morbidity than TPN. There is no evidence from this study to support a difference between the two modalities in terms of septic morbidity. Patients in whom there is reasonable doubt as to the adequacy of gastrointestinal function should be fed by the parenteral route.

Modulating effects of the feeding route on stress response and endotoxin translocation in severely stressed patients receiving thoracic esophagectomy

Experimental studies have demonstrated that the route of nutritional supply impacts the systemic metabolic responses after surgical injury. Intestinal mucosal atrophy, as induced by total parenteral nutrition (TPN) or prolonged bowel rest, has been reported to enhance bowel endotoxin translocation. The operative procedure for thoracic esophageal cancer, including thoracotomy, laparotomy, and three-field lymph-node dissection, is a particularly stressful surgery that requires long-term aggressive nutritional support and often results in the postoperative hypermetabolic state, leading to perturbation of postoperative immune function. Interleukin-6 (IL-6) plays an important role in host inflammatory responses, whereas IL-10 is linked to suppression of cellular immunity. The aim of this study was to investigate how the antecedent nutritional routes influence systemic IL-6 and IL-10 responses and endotoxin translocation after an operation for thoracic esophageal cancer. Twenty-nine patients who underwent esophagectomy with three-field lymphadenectomy were investigated. They were assigned to groups receiving either TPN (n = 18) or enteral nutrition (EN; n = 11) providing 35 kcal x kg(-1) x d(-1) of energy and approximately 1.2-1.5 g x kg(-1) x d(-1) of amino acids. These nutritional supports were conducted from 1 wk before the operation to 14 d after the operation. Serum IL-6, IL-10, and endotoxin concentration were measured before and during the operation and at 2 h and 1, 3, and 7 d after the operation. IL-6 in sera was significantly higher after the operation in both groups. In the EN group, however, significantly less IL-6 production was observed on the third and seventh postoperative days when compared with those patients in the TPN group. Similarly, serum IL-10 concentration in the TPN group showed a significantly higher level than that in the EN group. Serum IL-6 showed a significant positive correlation with IL-10 at 2 h and at 7 d after the operation, suggesting that the reduced inflammatory responses were related to the inhibition of the development of postoperative immunosuppression. Endotoxin concentration in sera was significantly lower in the EN group after the operation than in the TPN group. Perioperative EN provides better regulation of inflammatory cytokine responses and may contribute less to immunosuppression after major surgery than parenteral nutrition. The attenuated production of endotoxin induced by EN may play an important role in these phenomena.

Gastrointestinal complications in the intensive care unit

Pathologic conditions affecting the abdomen are a significant cause of morbidity and mortality in the intensive care unit, but their importance is not widely recognized. This article presents several aspects of abdominal pathology that can occur in intensive care unit patients. This pathology may have a considerable impact on the prognosis and survival of the critically ill patient. The diagnostic contribution of laboratory tests and imaging is discussed. Conditions such as the abdominal compartment syndrome, acute mesenteric ischemia, gastrointestinal bleeding, diarrhea, abdominal sepsis, complications of entereal and parenteral nutrition, and ileus in critically ill patients are also reviewed.

Gut mucosal atrophy after a short enteral fasting period in critically ill patients

PURPOSE

The purpose of this study was to evaluate the presence of gut mucosal atrophy and changes in mucosal permeability in critically ill patients after a short fasting period.

MATERIALS AND METHODS

Fifteen critically ill patients underwent a period of enteral fasting of at least 4 days (mean 7.8 days). We took the following measurements the day before initiating enteral nutrition: indirect calorimetry, serum albumin, prealbumin, and lymphocyte count. We also performed a duodenal endoscopic biopsy with histopathological and mucosal morphometric analysis including villus height and crypt depth. The lactulose-mannitol test was performed to assess gut permeability. A total of 28 healthy volunteers served as controls for duodenal biopsy or lactulose-mannitol test. Clinical data, such as length of fasting, severity score, and previous parenteral nutritional support, were recorded.

RESULTS

We found gut mucosal atrophy, expressed as a decrease in villus height and crypt depth, in patients compared with controls. The patients also exhibited an abnormal lactulose-mannitol test. Morphometric changes did not correlate with permeability. Further, we found no correlation between the results of the lactulose-mannitol test and of mucosal morphometry with clinical data.

CONCLUSIONS

We found that a short period of enteral fasting was associated with significant duodenal mucosal atrophy and abnormal gut permeability in critically ill patients.

Nutrition in the intensive care unit

Nutritional support has become a routine part of the care of the critically ill patient. It is an adjunctive therapy, the main goal of which is to attenuate the development of malnutrition, yet the effectiveness of nutritional support is often thwarted by an underlying hostile metabolic milieu. This requires that these metabolic changes be taken into consideration when designing nutritional regimens for such patients. There is also a need to conduct large, multi-center studies to acquire more knowledge of the cost-benefit and cost effectiveness of nutritional support in the critically ill.

Grains or veins: is enteral nutrition really better than parenteral nutrition? A look at the evidence

BACKGROUND

Enteral nutrition is said to be better than parenteral nutrition for providing nutrition support to humans.

PURPOSE

To assess the literature documenting the assertions that enteral nutrition is superior to parenteral nutrition with respect to cost, safety, physiology, intestinal structure and function, bacterial translocation, and outcome.

DATA IDENTIFICATION

Sources included MEDLINE search, personal files, and references from human comparative studies of enteral vs parenteral nutrition.

STUDY SELECTION

The goal was to include all human studies directly addressing questions of comparative efficacy of enteral and parenteral nutrition. Emphasis was given to prospective randomized controlled studies where available. Retrospective comparisons were not included.

DATA EXTRACTION

An attempt was made to briefly summarize methodology and findings of relevant studies. No general attempt was made to assess quality of individual studies.

RESULTS OF DATA SYNTHESIS

Enteral nutrition appears to be less expensive than parenteral nutrition, but new economic analyses are needed given the newer aggressive access techniques for enteral nutrition. Enteral nutrition is associated with meaningful morbidity and mortality. The little comparative data existent suggest no differences in safety. Comparative studies of physiology and metabolism as well as comparative and noncomparative studies of intestinal function and structure do not support putative advantages of enteral nutrition. There is no evidence that enteral nutrition prevents bacterial translocation in humans. Enteral nutrition probably reduces septic morbidity compared with parenteral nutrition in abdominal trauma. Otherwise, there is no evidence that enteral nutrition consistently improves patient outcome compared with parenteral nutrition.

CONCLUSIONS

With the exception of decreased cost and probable reduced septic morbidity in acute abdominal trauma, the available literature does not support the thesis that enteral nutrition is better than parenteral nutrition in humans.