Enteral versus parenteral feeding. Effects on septic morbidity after blunt and penetrating abdominal trauma

Randomised trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma

BACKGROUND

Infections are an important cause of morbidity and mortality in patients with multiple trauma. Studies in both animals and human beings have suggested that glutamine-enriched nutrition decreases the number of infections.

METHODS

Patients with multiple trauma with an expected survival of more than 48 h, and who had an Injury Severity Score of 20 or more, were randomly allocated glutamine supplemented enteral nutrition or a balanced, isonitrogenous, isocaloric enteral-feeding regimen along with usual care. Each patient was assessed every 8 h for infection, the primary endpoint. Data were analysed both per protocol, which included enteral feeding for at least 5 days, and by intention to treat.

FINDINGS

72 patients were enrolled and 60 received enteral feeding (29 glutamine-supplemented) for at least 5 days. Five (17%) of 29 patients in the glutamine-supplemented group had pneumonia compared with 14 (45%) of 31 patients in the control group (p<0.02). Bacteraemia occurred in two (7%) patients in glutamine group and 13 (42%) in the control group (p<0.005). One patient in the glutamine group had sepsis compared with eight (26%) patients in the control group (p<0.02).

INTERPRETATION

There was a low frequency of pneumonia, sepsis, and bacteraemia in patients with multiple trauma who received glutamine-supplemented enteral nutrition. Larger studies are needed to investigate whether glutamine-supplemented enteral nutrition reduces mortality.

Total parenteral nutrition supplemented with medium-chain triacylglycerols prevents atrophy of the intestinal mucosa in septic rats

Total parenteral nutrition (TPN) is associated with an increased incidence of bacterial translocation (BT) compared with enteral nutrition because of the disuse atrophy of the intestine. In this study, we assessed the effect of adding medium-chain triacylglycerols (MCT) to TPN for the prevention of mucosal atrophy in the intestine. Rats were subjected to either fat-free TPN, TPN with long-chain triacylglycerols (LCT), or TPN with MCT for 5 d and nutrition parameters were evaluated. In another set of rats receiving the same TPN regimen, 0.8 or 0.05 mg/kg endotoxin was administered on day 4. Survival was evaluated and BT to the mesenteric lymph nodes, liver, and systemic blood was measured 24 h later. The mucosal heights of the jejunum and ileum were evaluated concurrently. The survival rate was significantly improved in the MCT group (P < 0.05) at the endotoxin dose of 0.8 mg/kg. The nutrition condition presented by phospholipid, total cholesterol, and total ketone body levels was the best in the MCT group compared to the other groups. The intestinal villous height in the ileum was significantly greater in the MCT group. However, the improvement of BT in MCT group was not statistically significant. In this endotoxin-challenged rat model, survival rate was improved by the supplementation of MCT. This effect may be presented in some part by the improvement in nutrition condition and by the prevention of mucosal atrophy in the intestine.

The route of nutrition support affects the early phase of wound healing

BACKGROUND

Nutrition support via the enteral route has been shown to be superior to parenteral administration in maintaining immune function, decreasing septic complications, and increasing survival after severe trauma and surgical injury. Whether the route of nutrition support affects wound healing, another important determinant of outcome following injury, is not known.

METHODS

Forty-nine Sprague-Dawley rats, 290 to 360 g body wt, underwent identical surgical manipulation consisting of central venous catheterization, fashioning of gastrostomy and dorsal skin incision, and placement of polyvinyl alcohol sponges into subcutaneous pockets. Identical infusates of 25% dextrose, 4.25% amino acids, and vitamins were given, half the animals receiving the infusion via the gastrostomy and the other half via the venous catheter. Animals were killed on day 5, 7, or 10. Wound breaking strength, sponge hydroxyproline content (an index of wound collagen deposition), and types I and III collagen gene expression were measured.

RESULTS

There were no nutritional differences between the two groups in terms of energy intake, body weight gain, and plasma levels of albumin, total protein, or urea nitrogen. On day 5 wound breaking strength was significantly higher in the enterally supported group (89.3 +/- 90.7 vs 64.9 +/- 40.2 g for the parenteral group, p < .05). This was paralleled by enhanced wound collagen accumulation (182 +/- 19 vs 132 +/- 13 microg, p < .05). Gene expression of type I, but not type III, collagen also was increased in the enterally fed group. There were no differences noted between the two groups in wound healing parameters 7 and 10 days after injury.

CONCLUSIONS

The data demonstrate that the route of nutrition administration can influence wound healing. The beneficial effect of the enteral feeding route is limited to the early phases of healing.

Optimal protein requirements during the first 2 weeks after the onset of critical illness

OBJECTIVE

To obtain optimal protein requirements in critically ill sepsis or trauma patients during the first 2 wks after admission to the intensive care unit.

DESIGN

Retrospective study.

SETTING

Department of critical care medicine at a teaching hospital.

PATIENTS

Immediate posttrauma patients or severely septic patients.

INTERVENTIONS

In vivo neutron activation analysis was used to measure changes in total body protein over a 10-day period which began as soon as the patients were hemodynamically stable. The patients (trauma, n=18; sepsis, n=5) were divided into three groups according to the average daily protein intakes. Because the patients were overhydrated (approximately 10 L) and had variable amounts of body fat, the protein intakes were indexed to normally hydrated (corrected) fat-free mass (FFMc): Groups A, B, and C received an average of 1.1, 1.5, and 1.9 g/kg FFMc/day protein, respectively.

MEASUREMENTS AND MAIN RESULTS

Overall, the average loss of total body protein was 1.2=0.7 (SD) kg. Changes in total body protein were significantly (p=.011) different between the three groups. The loss of body protein was significantly more in group A compared with groups B (p=.013) and C (p=.023). When the protein intake was increased from 1.1 g/kg FFMc/day to 1.5 g/kg FFMc/day, protein loss was halved. Further increase in protein intake up to 1.9 g/kg FFMc/day resulted in no further improvement. An intake of 1.5 g/kg FFMc/day was equivalent to 1.0 g/day/kg of body weight measured at the beginning of the study.

CONCLUSIONS

Current recommended protein requirements of 1.2 to 2.0 g/kg of body weight/day are excessive if they are indexed to the body weight measured soon after the onset of critical illness. Because individual patients have varying degrees of overhydration early in the illness onset, we suggest that the intensivist should obtain information on preillness body weight and prescribe 1.2g of protein/kg body weight/day. If information is not available, 1.0g of protein/day/kg of measured body weight will give a fair approximation to optimal protein requirements.

Enteral nutrition in intensive care patients: a practical approach. Working Group on Nutrition and Metabolism, ESICM. European Society of Intensive Care Medicine

Severe protein-calorie malnutrition is a major problem in many intensive care (ICU) patients, due to the increased catabolic state often associated with acute severe illness and the frequent presence of prior chronic wasting conditions. Nutritional support is thus an important part of the management of these patients. Over the years, enteral nutrition (EN) has gained considerable popularity, due to its favorable effects on the digestive tract and its lower cost and rate of complications compared to parenteral nutrition. However, clinicians caring for ICU patients are often faced with contradictory data and difficult decisions when having to determine the optimal timing and modalities of EN administration, estimation of patient requirements, and choice of formulas. The purpose of this paper is to provide practical guidelines on these various aspects of enteral nutritional support, based on presently available evidence.

Nutritional modulation of gut inflammation

Nutritional therapy is an important component of the management of gastrointestinal inflammation, which disrupts the gut mucosal barrier leading to sepsis, SIRS and MODS. Future studies will be needed to define the role of specific nutrients in enhancing mucosal barrier function and supporting general immune function, and how this affects morbidity and mortality of critically-ill patients.

Oral beclomethasone dipropionate for treatment of intestinal graft-versus-host disease: a randomized, controlled trial

BACKGROUND & AIMS

Beclomethasone dipropionate (BDP), a topically active steroid, seemed to be an effective treatment for intestinal graft-versus-host disease (GVHD) in a phase I study. The aim of this study was to compare the effectiveness of oral BDP to that of placebo capsules in treatment of intestinal GVHD.

METHODS

Sixty patients with anorexia and poor oral intake because of intestinal GVHD were randomized to receive prednisone (1 mg.kg-1.day-1) plus either oral BDP (8 mg/day) or placebo capsules. Initial responders who were eating at least 70% of caloric needs at evaluation on day 10 continued to take study capsules for an additional 20 days while the prednisone dose was rapidly tapered. The primary end point was the frequency of a durable treatment response at day 30 of treatment.

RESULTS

The initial treatment response at day 10 was 22 of 31 (71%) in the BDP/prednisone group vs. 16 of 29 (55%) for the placebo/prednisone group. The durable treatment response at day 30 was 22 of 31 (71%) vs. 12 of 29 (41%), respectively (P = 0.02).

CONCLUSIONS

The combination of oral BDP capsules and prednisone was more effective than prednisone alone in treating intestinal GVHD. Oral BDP allowed prednisone doses to be rapidly tapered without recurrent intestinal symptoms.

Nutritional support in the critically ill patients. A critical review of the evidence

Providing nutritional support has become a standard component of managing critically ill patients. While many studies have documented that providing nutritional support can change nutritional outcomes (e.g., amino acid profile, weight gain, nitrogen balance), data are lacking that demonstrate that nutrition actually influences clinically importance endpoints. This article systematically reviews and critically appraises the literature, examining the relationship between nutritional support and infectious morbidity and mortality in the critically ill patient. In addition, evidence-based recommendations are made.

A prospective, randomized, double-blind, controlled clinical trial of enteral immunonutrition in the critically ill. Guy's Hospital Intensive Care Group

OBJECTIVE

To assess the effects of enteral immunonutrition (IMN) on hospital mortality and length of stay in a heterogeneous group of critically ill patients.

DESIGN

Prospective, randomized, double-blind, controlled clinical trial with an a priori subgroup analysis according to the volume of feed delivered in the first 72 hrs of intensive care unit (ICU) admission.

SETTING

A 13-bed adult general ICU in a London teaching hospital.

PATIENTS

A total of 398 patients were enrolled and data from 390 patients (IMN = 193, control = 197) were used for an intention-to-treat analysis. There were 369 patients (IMN = 184, control = 185) who actually received some enteral nutrition, of whom 101 patients (IMN = 50, control = 51) received >2.5 L within 72 hrs of ICU admission. This latter group was defined as the successful "early enteral nutrition" group.

INTERVENTIONS

Within 48 hrs of ICU admission, patients were randomized to receive either the IMN Impact (Novartis Nutrition), an enteral feed supplemented with arginine, purine nucleotides and omega-3 fatty acids, or an isocaloric, isonitrogenous control enteral feed.

MEASUREMENTS AND RESULTS

There was no significant difference in hospital mortality rate between the two groups on an intention-to-treat analysis (Impact group 48%, control group 44%) nor in any other predefined subgroup analysis. However, patients randomized to receive the IMN had higher Acute Physiology and Chronic Health Evaluation II scores (20.1 +/- 7.1 vs. 18.7 +/- 7.1 [p = .07] intention-to-treat [n = 390]; 20.1 +/- 7.2 vs. 18.5 +/- 7.1 [p = .04] received feed [n = 369]). Of the 101 patients achieving early enteral nutrition, those patients fed with the IMN had a significant reduction in their requirement for mechanical ventilation compared with controls (median duration of ventilation 6.0 and 10.5 days, respectively, p = .007) with an associated reduction in the length of hospital stay (medians 15.5 and 20 days, respectively, p = .03).

CONCLUSION

While the administration of enteral IMN to a general, critically ill population did not affect mortality, those patients in whom it was possible to achieve early enteral nutrition with Impact had a significant reduction in the morbidity of their critical illness.

Preoperative oral supplement with immunonutrients in cancer patients

BACKGROUND

Early postoperative enteral nutrition with immune-enhancing supplements has helped to restore immune function and reduce infectious complications in patients with cancer undergoing major gastrointestinal operations. The aim of this study was to evaluate the effectiveness of similar supplements (containing arginine and arginine plus omega-3 fatty acids) given preoperatively for 1 week before cancer surgery.

METHODS

In this randomized, double-blinded study, patients scheduled to undergo elective resection of upper gastrointestinal tumors were given one of three different oral liquid supplemental diets (control, arginine, arginine plus omega-3 fatty acids) to be taken each day for 7 days before surgery. Blood samples were obtained upon enrollment, on the morning of surgery, and on postoperative day 1 for analysis of immunologic function.

RESULTS

Mean serum ornithine (a metabolite of arginine) levels were significantly higher compared with controls, but no significant increase in mean serum arginine levels was noted on the morning of surgery for those patients who received arginine as part of the supplement. In conjunction with these findings, there were no differences among groups in mean lymphocyte mitogenesis, mean peripheral blood mononuclear cell production of cytokines, or clinical outcomes.

CONCLUSIONS

Use of oral liquid supplements in this fashion did not improve lymphocyte proliferation or monocyte functions in patients with cancer undergoing major surgery.

Nutritional management in acute and chronic pancreatitis

Patients with severe pancreatitis, characterized by multiple organ failure and pancreatic necrosis on CT scan (identified by an Acute Physiology and Chronic Health Evaluation II score of > or = 10 with > or = 3 Ranson criteria), most likely require aggressive nutritional support. Use of the enteral route of feeding may help contain the hypermetabolic stress response, reduce morphologic change and atrophy of the gut, and theoretically decrease late complications of nosocomial infection and organ failure. Evidence that decreasing degrees of stimulation of the pancreas occur as the site of feeding descends in the gastrointestinal tract and evidence from perspective, randomized trials suggest that jejunal feeding appears at least as safe and well tolerated as total parenteral nutrition in acute pancreatitis.

Enteral nutrition

This article briefly reviews the literature supporting the use of enteral nutrition, which appears to be the preferred method of nutritional support in critically ill patients. Patients who benefit the most from this type of support, as well as the administration and route preferences in enteral nutrition, are discussed. In addition, the different types of enteral formulas and the more frequently associated complications that occur with tube feedings are reviewed.

Early enteral nutrition in surgical patients

There is increasing evidence that delivery of nutrients via the gastrointestinal tract reduces the septic morbidity in severely injured patients. This article reviews the most current data and also reviews the importance of the gut-associated lymphoid tissue as an important factor in maintaining the host defenses.

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.

Elective bedside surgery in critically injured patients is safe and cost-effective

OBJECTIVE

The success of elective minimally invasive surgery suggested that this concept could be adapted to the intensive care unit. We hypothesized that minimally invasive surgery could be done safely and cost-effectively at the bedside in critically injured patients.

SUMMARY BACKGROUND DATA

This case series, conducted between October 1991 and June 1997 at a Level I trauma center, examined bedside dilatational tracheostomy (BDT), percutaneous endoscopic gastrostomy (PEG), and inferior vena cava (IVC) filter placement. All procedures had been performed in the operating room (OR) before initiation of this study.

METHODS

All BDTs and PEGs were performed with intravenous general anesthesia (fentanyl, diazepam, and pancuronium) administered by the surgical team. IVC filters were placed using local anesthesia and conscious sedation. BDTs were done using a Ciaglia set, PEGs were done using a 20 Fr Flexiflow Inverta-PEG kit, and IVC filters were placed percutaneously under ultrasound guidance. Cost difference (delta cost) was defined as the difference in hospital cost and physician charges incurred in the OR as compared to the bedside.

RESULTS

Of 16,417 trauma admissions, 379 patients (2%) underwent 472 minimally invasive procedures (272 BDTs, 129 PEGs, 71 IVC filters). There were four major complications (0.8%). Two patients had loss of airway requiring reintubation. Two patients had an intraperitoneal leak from the gastrostomy requiring operative repair. No patient had a major complication after IVC filter placement. Total delta cost was $611,994. When examined independently, the cost was $324,224 for BDT, $164,088 for PEG, and $123,682 for IVC filter. OR use was reduced by 506 hours.

CONCLUSIONS

These bedside procedures have minimal complications, eliminate the risk associated with patient transport, reduce cost, improve OR utilization, and should be considered for routine use in the general surgery population.

The principles and practical application of enteral nutrition

The enteral route is the preferred method of nutritional support in patients with functional gastrointestinal tracts. Many techniques for obtaining enteral access are available, and the decision regarding which one to use depends on several issues, including the functional integrity of each part of the gastrointestinal tract, the duration of anticipated nutritional support, and the risk of aspiration and gastroesophageal reflux. Nasoesophageal tubes are useful for short-term supplementation; however, patients needing nutritional support for longer than 2 weeks may be better served with a more permanent tube. Blenderized pet food diets are recommended for nutritional support because these diets do not need to be supplemented with protein or micronutrients. Commercial human enteral formulas provide a useful alternative for patients with specific nutrient requirements or for feeding via nasoesophageal or jejunostomy tubes.

Pharmacological nutrition after burn injury

Burn patients develop pathophysiological alterations, which include extensive nitrogen loss, malnutrition, markedly increased metabolic rate and immunologic deficiency. This predisposes burn patients to frequent infections, poor wound healing, increased length of hospitalization and increased mortality. The nutritional support requires high protein and high energy diets preferably administered enterally soon after injury. The effects of increased dietary components such as glutamine, arginine and (n-3) fatty acids and related compounds have been evaluated in burn victims. These components, when supplied in quantities two to seven times of those in normal diets of healthy persons, appear to have beneficial pharmacological effects on the pathophysiological alterations associated with burns. However, the efficacy of immune-enhancing diets remains to be convincingly shown.

Lymphocyte function in wound healing and following injury

BACKGROUND

Injury activates a cascade of local and systemic immune responses.

METHODS

A literature review was undertaken of lymphocyte function in wound healing and following injury.

RESULTS

Lymphocytes are not required for the initiation of wound healing, but an intact cellular immune response is essential for a normal outcome of tissue repair. Injury affects lymphocyte immune mechanisms leading to generalized immunosuppression which, in turn, increases host susceptibility to infection and sepsis. Although the exact origin of post-traumatic immunosuppression remains unknown, stress hormones and immunosuppressive factors, such as inflammatory cytokines, prostaglandin E2 and nitric oxide, affect lymphocyte function adversely. Post-traumatic impairment of T lymphocyte immune function is reflected in decreased lymphocyte numbers, as well as altered T cell phenotype and activity. Antibody-producing B lymphocytes are variably affected by injury, probably secondary to alterations of T lymphocyte function, as a result of their close interaction with helper T cells. Therapeutic modulation of the host immune response may include non-specific and specific interventions to improve overall defence mechanisms.

CONCLUSION

Early resuscitation to restore lymphocyte function after injury is important for tissue repair and the prevention of immunosuppression.

Enteral nutrition is superior to parenteral nutrition in severe acute pancreatitis: results of a randomized prospective trial

BACKGROUND

Parenteral nutrition is well established for providing nutritional support in acute pancreatitis while avoiding pancreatic stimulation. However, it is associated with complications and high cost. Benefits of enteral feeding in other disease states prompted a comparison of early enteral feeding with total parenteral nutrition in this clinical setting.

METHODS

Thirty-eight patients with acute severe pancreatitis were randomized into two groups. The first (n = 18) received enteral nutrition through a nasoenteric tube with a semi-elemental diet, while the second group (n = 20) received parenteral nutrition through a central venous catheter. Safety was assessed by clinical course of disease, laboratory findings and incidence of complications. Efficacy was determined by nitrogen balance. The cost of nutritional support was calculated.

RESULTS

Enteral feeding was well tolerated without adverse effects on the course of the disease. Patients who received enteral feeding experienced fewer total complications (P < 0.05) and were at lower risk of developing septic complications (P < 0.01) than those receiving parenteral nutrition. The cost of nutritional support was three times higher in patients who received parenteral nutrition.

CONCLUSION

This study suggests that early enteral nutrition should be used preferentially in patients with severe acute pancreatitis.

Total enteral nutrition versus total parenteral nutrition during pediatric extracorporeal membrane oxygenation

OBJECTIVE

To evaluate the adequacy, tolerance, and complications of enteral nutrition, compared with parenteral nutrition, in pediatric patients requiring extracorporeal membrane oxygenation (ECMO).

DESIGN

A retrospective chart review of all patients placed on extracorporeal life support from January 1991 through December 1995.

SETTING

Medical/surgical pediatric intensive care unit at Egleston Children's Hospital, a tertiary care pediatric center.

PATIENTS

Twenty-nine consecutive pediatric patients who required ECMO and were provided nutritional support, either enterally or parenterally. Group A consisted of 14 patients who were provided nutritional support using total parenteral nutrition. Group B consisted of 15 patients. Two patients were excluded from group B because their ECMO run was <36 hrs, leaving insufficient data for analysis. The remaining 13 patients were provided total enteral nutrition during ECMO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Both groups were similar in age, weight, pre-ECMO oxygenation index, alveolar-arterial oxygen difference, type, and duration of ECMO (p = NS). Comparison of percent ideal body weight on admission did not show a statistical difference between groups A and B (p = .883). There was no difference between the two groups in the time needed to achieve caloric goal (p = .536) from the initiation of ECMO. No complications were associated with the utilization of enteral feedings. Savings for the nutritional supplement was estimated to be $170 per day for the enterally fed group. The percentage of patients surviving was higher in the enterally fed patients compared with the parenterally fed group (79% vs. 100%), although this difference was not statistically significant (p = .47).

CONCLUSIONS

Enteral nutrition in patients receiving either venoarterial or venovenous ECMO is well tolerated, provides adequate nutrition, is cost effective, and is without complications, as compared with parenteral nutrition. These data suggest that total enteral nutrition can be safely administered for nutritional support in pediatric patients undergoing either venoarterial or venovenous ECMO.

Disease-associated malnutrition in the year 2000

Malnutrition is associated with increased morbidity and mortality and is common in patients admitted to hospital. Nutritional status is not routinely assessed on admission, and nutritional depletion escapes recognition in the majority of affected patients. Nutritional status declines during hospital stay, and this trend is most marked in patients who are already malnourished on admission. Techniques for nutritional support are available, their appropriate use leads to improved nutritional status and clinical outcome in most patients. There is evidence that the current use of artificial nutrition is suboptimal and associated with a high complication rate. The introduction of clinical guidelines and the formation of nutrition support teams will improve nutritional management in the future. The development of new substrates and 'pharmaconutrition' is likely to further improve the outcome for many patients. There will remain a need for more studies to define the cost efficacy of artificial nutrition across a broad spectrum of clinical practice.

Postoperative nutrition in surgery for major trauma

Research in the area of the nutritional support of trauma patients has continued to focus on a few main areas: the effect that the route, timing and type of feeding has on patient outcome, nutritional assessment and mucosal immunity. This year a nutritional conference has released a paper, summarizing the current state of research in this area, that generated some controversy.

Glycyl-L-glutamine-enriched total parenteral nutrition maintains small intestine gut-associated lymphoid tissue and upper respiratory tract immunity

BACKGROUND

i.v. administration of a total parenteral nutrition (TPN) solution results in small intestinal gut-associated lymphoid tissue (GALT) atrophy, lowers small intestinal immunoglobulin A (IgA) levels, and impairs upper respiratory tract secretory IgA-mediated mucosal immunity; isonitrogenous supplementation of TPN with 2% glutamine attenuates these changes. This experiment examines whether a 2% glycyl-L-glutamine-enriched TPN solution reverses i.v. TPN-induced changes as effectively as L-glutamine.

METHODS

Male Institute of Cancer Research (ICR) mice underwent intranasal inoculation with H1N1 influenza virus to establish immunity. After 3 weeks, mice were randomized to chow, i.v. feeding of a TPN solution, glutamine-enriched TPN, or glycyl-L-glutamine-enriched TPN. After 4 days of feeding, mice were challenged intranasally with influenza virus and killed at 40 hours to determine viral shedding from the respiratory tract; normal convalescent mice do not shed virus because they possess intact IgA-mediated mechanisms Lymphocytes were isolated from Peyer's patches, the intraepithelial layer, and lamina propria to determine cell yields.

RESULTS

Total lymphocyte yield in the Peyer's patches, the intraepithelial layer, and lamina propria decreased with TPN but remained normal with glutamine and glycyl-L-glutamine. Upon challenge, 70% of the mice in the TPN group shed virus in nasal secretions, whereas only 20% of the glutamine-treated group, 18% of glycyl-L-glutamine group and none of the Chow group were virus positive.

CONCLUSIONS

L-Glutamine and glycyl-L-glutamine have similar effects on i.v. administered TPN-associated (GALT) atrophy and decreased upper respiratory tract immunity.

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.

Perioperative nutrition: parenteral versus enteral

Malnutrition has been shown to have an adverse effect on the clinical outcome of surgical patients. During the past 25 years, investigators have sought to determine whether clinical outcome can be improved by the administration of pre- or postoperative (perioperative) nutritional support. We conclude that the clinical outcome of severely malnourished surgical patients is improved by perioperative nutritional support and that this should be administered whenever possible via the enteral route. The clinical outcome of less severely malnourished surgical patients, including those who are normally nourished, can be improved by the administration of oral dietary supplements at a time in the postoperative period when patients are ingesting free fluids. Some of these patients may also benefit from early postoperative enteral tube feeding, but further work is required to determine the effects following different types of surgery before this is adopted for routine use. Parenteral nutrition is only indicated in the postoperative period when major complications occur in association with intestinal failure.

Artificial nutrition after major abdominal surgery: impact of route of administration and composition of the diet

OBJECTIVE

To evaluate the impact of the route of administration of artificial nutrition and the composition of the diet on outcome.

DESIGN

Prospective, randomized, clinical trial.

SETTING

Department of surgery, university hospital.

PATIENTS

One hundred sixty-six consecutive patients undergoing curative surgery for gastric or pancreatic cancer.

INTERVENTIONS

At operation, the patients were randomized into three groups to receive: a) a standard enteral formula (control group; n = 55); b) the same enteral formula enriched with arginine, RNA, and omega-3 fatty acids (enriched group; n = 55); and c) total parenteral nutrition (TPN group; n = 56). The three regimens were isocaloric and isonitrogenous. Enteral nutrition was started within 12 hrs following surgery. The infusion rate was progressively increased to reach the nutritional goal (25 kcal/kg/day) on postoperative day 4.

MEASUREMENTS AND MAIN RESULTS

Tolerance of enteral feeding, rate and severity of postoperative complications, and length of hospital stay were recorded. Early enteral infusion was well tolerated. Side effects were recorded in 22.7% of the patients, but only 6.3% did not reach the nutritional goal. The enriched group had a lower severity of infection than the parenteral group (4.0 vs. 8.6; p < .05). In subgroups of malnourished (n = 78) and homologous transfused patients (n = 42), the administration of the enriched formula significantly reduced both severity of infection and length of stay compared with the parenteral group (p < .05). Moreover, in transfused patients, the rate of septic complications was 20.0% in the enriched group, 38.4% in the control group, and 42.8% in the TPN group.

CONCLUSIONS

Early enteral feeding is a suitable alternative to TPN after major abdominal surgery. The use of the enriched diet appears to be more beneficial in malnourished and transfused patients.

Immunonutrition

The immune system is designed to protect the individual from foreign substances or organisms. It is expressed as cellular and humoral immunity. The former is dependent upon T lymphocytes and the latter on B lymphocytes, which become plasma cells and secrete antibodies. The immune system can be influenced by protein-energy malnutrition (PEM) and by catabolic illnesses such as sepsis and trauma, which in turn cause PEM. Specific trace element and vitamin deficiencies can also alter the immune state. However, overnutrition and obesity can also influence immune mechanisms. Obesity can promote the development of diabetes, which can alter the immune state. Finally, immunity becomes less effective with ageing and this process is enhanced by associated malnutrition.

Prospective, randomized trial on the effect of cyclic versus continuous enteral nutrition on postoperative gastric function after pylorus-preserving pancreatoduodenectomy

OBJECTIVE

The effect of a cyclic versus a continuous enteral feeding protocol on postoperative delayed gastric emptying, start of normal diet, and hospital stay was assessed in patients undergoing pylorus-preserving pancreatoduodenectomy (PPPD).

SUMMARY BACKGROUND DATA

Delayed gastric emptying occurs in approximately 30% of patients after PPPD and causes prolonged hospital stay. Enteral nutrition through a catheter jejunostomy is used to provide postoperative nutritional support. Enteral infusion of fats and proteins activates neurohumoral feedback mechanisms and therefore can potentially impair gastric emptying and prolong postoperative gastroparesis.

METHODS

From September 1995 to December 1996, 72 consecutive patients underwent PPPD at the Academic Medical Center, Amsterdam. Fifty-seven patients were included and randomized for either continuous (CON) jejunal nutrition (0-24 hr; 1500 kCal/24 hr) or cyclic (CYC) enteral nutrition (6-24 hr; 1125 kCal/18 hr). Both groups had an equal caloric load of 1 kCal/min. The following parameters were assessed: days of nasogastric intubation, days of enteral nutrition, days until normal diet was tolerated orally, and hospital stay. On postoperative day 10, plasma cholecystokinin (CCK) levels were measured during both feeding protocols.

RESULTS

Nasogastric intubation was 9.1 days in the CON group (n = 30) and 6.7 days in the CYC group (n = 27) (not statistically significant). First day of normal diet was earlier for the CYC group (15.7 vs. 12.2 days, p < 0.05). Hospital stay was shorter in the CYC group (21.4 vs. 17.5 days, p < 0.05). CCK levels were lower in CYC patients, before and after feeding, compared with CON patients (p < 0.05).

CONCLUSIONS

Cyclic enteral feeding after PPPD is associated with a shorter period of enteral nutrition, a faster return to a normal diet, and a shorter hospital stay. Continuously high CCK levels could be a cause of prolonged time until normal diet is tolerated in patients on continuous enteral nutrition. Cyclic enteral nutrition is therefore the feeding regimen of choice in patients after PPPD.

Nonradiographic assessment of enteral feeding tube position

OBJECTIVE

To determine whether a clinical, nonradiographic criterion can be used to predict when the tip of a blindly placed feeding tube is in the small intestine.

DESIGN

Prospective sample.

SETTING

Pediatric intensive care unit at a tertiary care children's hospital.

PATIENTS

Critically ill children requiring transpyloric feeding.

INTERVENTIONS

The small bowel was intubated, using a blind, bedside transpyloric feeding tube placement protocol. The feeding tube was considered to be in the small bowel when <2 mL of a 10- mL aliquot of insufflated air could be aspirated from the feeding tube. This clinical criterion was confirmed with an abdominal radiograph.

MEASUREMENTS AND MAIN RESULTS

Patient age ranged from 1 month to 19 yrs (median 6 months). Weight ranged from 2.2 to 60 kg (median 4.9). Median time to feeding tube placement was 10 mins (range 5 to 60). Eighty-nine percent of the patients were mechanically ventilated, while 28% of these patients were pharmacologically paralyzed. Seventy-five feeding tubes were inserted. There were no known complications. Ninety-nine (74/75) percent of the feeding tubes were positioned in the small bowel. The inability to aspirate insufflated air correctly predicted small bowel intubation with 99% certainty (Sequential Probability Ratio Test, p = .05 and power = .80). This test incorrectly predicted the position of only one feeding tube, the 26th, which was in the stomach. Of the 74 feeding tubes positioned in the small bowel, 13 feeding tubes were in the duodenum and 61 were in the jejunum.

CONCLUSIONS

The inability to aspirate insufflated air confirms the transpyloric position of a feeding tube. Other clinical criteria did not successfully predict small bowel intubation. Use of this single test may obviate confirmatory abdominal radiographs in carefully selected patients and may lead to more cost-effective and timely initiation of enteral feedings.

Accelerated nitrogen loss after traumatic injury is not attenuated by achievement of energy balance

BACKGROUND

We wanted to determine if achievement of energy balance decreases myofibrillar protein catabolism and nitrogen loss during posttraumatic catabolic illness.

METHODS

Surgical intensive care unit of a level I trauma center in a university medical center. Trauma patients expected to be mechanically ventilated for at least 4 days were randomly assigned to one of three parenteral feeding groups: (1) nonprotein calorie group: dextrose and lipid intake equal to measured energy expenditure; (2) total calorie group: dextrose, lipid, and protein intake equal to measured energy expenditure; and (3) hypocaloric group: dextrose and lipid intake equal to 50% of measured energy expenditure. Target protein intake for all groups was 1.7 g/kg body wt. On day 4 of nutrition support, a 24-hour balance study was conducted. Urine urea and total nitrogen production, 3-methylhistidine excretion, energy expenditure, and substrate utilization were measured.

RESULTS

Despite significant differences in nonprotein and total calorie balance among the groups, nitrogen loss, nitrogen balance, and catabolic rate were not significantly different. Nitrogen loss correlated with catabolic rate but not with energy expenditure or energy balance. Catabolic rate was associated with energy expenditure but not with energy balance. Nitrogen loss was positively correlated with the percentage of nonprotein energy expenditure met by nonprotein calorie intake.

CONCLUSIONS

Achievement of energy balance (nonprotein or total energy) failed to decrease catabolic rate or nitrogen loss acutely in multiple trauma patients. Provision of caloric intake equal to energy expenditure does not seem necessary during the acute phase of posttraumatic catabolic illness.

A prospective, randomized trial of early enteral feeding after resection of upper gastrointestinal malignancy

OBJECTIVE

The purpose of the study was to determine whether early postoperative enteral feeding with an immune-enhancing formula (IEF) decreases morbidity, mortality, and length of hospital stay in patients with upper gastrointestinal (GI) cancer.

SUMMARY BACKGROUND DATA

Early enteral feeding with an IEF has been associated with improved outcome in trauma and critical care patients. Evaluable data documenting reduced complications after major upper GI surgery for malignancy with early enteral feeding are limited.

METHODS

Between March 1994 and August 1996, 195 patients with a preoperative diagnosis of esophageal (n = 23), gastric (n = 75), peripancreatic (n = 86), or bile duct (n = 11) cancer underwent resection and were randomized to IEF via jejunostomy tube or control (CNTL). Tube feedings were supplemented with arginine, RNA, and omega-3 fatty acids, begun on postoperative 1, and advanced to a goal of 25 kcal/kg per day. The CNTL involved intravenous crystalloid solutions. Statistical analysis was by t test, chi square, or logistic regression.

RESULTS

Patient demographics, nutritional status, and operative factors were similar between the groups. Caloric intake was 61% and 22% of goal for the IEF and CNTL groups, respectively. The IEF group received significantly more protein, carbohydrate, lipids and immune-enhancing nutrients than did the CNTL group. There were no significant differences in the number of minor, major, or infectious wound complications between the groups. There was one bowel necrosis associated with IEF requiring reoperation. Hospital mortality was 2.5% and median length of hospital stay was 11 days, which was not different between the groups.

CONCLUSION

Early enteral feeding with an IEF was not beneficial and should not be used in a routine fashion after surgery for upper GI malignancies.

Clinical nutrition in pancreatitis

In patients with acute pancreatitis or an acute flare of chronic pancreatitis, a discrepancy exists between increased protein/calorie requirements induced by a hypermetabolic stress state and reduced ingestion/assimilation of exogenous nutrients, which promotes progressive nutritional deterioration. Patients with severe pancreatitis (defined by > or =3 Ranson criteria, an APACHE II score of > or =10, development of major organ failure, and/or presence of pancreatic necrosis) are more likely to require aggressive nutritional support than patients with mild disease. The type of formula and level of the gastrointestinal tract into which nutrients are infused determine the degree to which pancreatic exocrine secretion is stimulated. Animal studies and early prospective randomized controlled trials in humans suggest that total enteral nutrition via jejunal feeding may be the preferred route to parenteral alimentation in this disease setting.