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

Short-chain fatty acid-supplemented total parenteral nutrition improves nonspecific immunity after intestinal resection in rats

BACKGROUND

Total parenteral nutrition (TPN) alters both specific and nonspecific immune functions, resulting in immunosuppression. Short-chain fatty acids have been shown to improve the adaptive responses of the gut after surgery. The following study investigates the effects of adding short-chain fatty acids to TPN on the immune system after an 80% small bowel resection.

METHODS

Rats (237 +/- 3 g) were infused with either TPN (n = 25) or TPN supplemented with short-chain fatty acids (n = 26) for 3 or 7 days. Hematologic analysis was performed on peripheral blood and splenocytes were isolated to characterize cell phenotypes, natural killer cell cytotoxicity and to estimate proliferative response.

RESULTS

The relative percent of T (CD3+) cells increased (p < .05) and the relative percent of macrophages decreased (p < .001, n = 13) in the spleens of the 3-day TPN-fed rats. By day 7, these differences disappeared. The natural killer cells from rats that were supplemented with short-chain fatty acids had higher (p < .0001) cytotoxic activity than the TPN groups at day 3. Mitogenic response did not differ between groups but were depressed compared with sham-treated rats. By day 7, rats on standard TPN had larger (p < .0001) spleens than all other groups. This group also had a higher total white blood cell count because of increased numbers of macrophages and neutrophils (p < .02).

CONCLUSION

Short-chain fatty acids improve components of nonspecific immune responses and may be beneficial in reducing certain aspects of TPN-associated immunosuppression after major surgery.

Low-dose enteral feeding is beneficial during total parenteral nutrition

BACKGROUND

Enteral support is the preferred feeding route for stressed patients due in part to the provision of gut-specific fuels. In those patients who must be maintained parenterally, small amounts of enteral stimulation might blunt gut atrophy and lead to improvement in host defense mechanisms decreasing macromolecular and/or bacterial translocation (BT).

METHODS

Forty-eight rats were infused with TPN for 9 days, and were randomized to receive 0%, 6%, 12%, or 25% of their calories as partial enteral nutrition (PEN) in an isocaloric, isonitrogenous fashion. Twenty-four hours before harvest animals were gavaged with lactulose and urinary excretion quantified. At harvest, mesenteric lymph nodes were cultured to assess BT and intestinal histology determined.

RESULTS

Provision of as little as 25% of total calories PEN improved nitrogen balance and reduced BT, in a dose dependent fashion. It did not alter TPN-associated increased macromolecular lactulose permeability (4.4% +/- 1.0%).

CONCLUSION

Concurrent small amounts of PEN, aimed to support the gut's metabolic needs, are beneficial during periods of prolonged TPN.

Effect of malnutrition after acute stroke on clinical outcome

BACKGROUND AND PURPOSE

Malnutrition has received little attention in acute stroke, although it represents a risk of decreased immunity and nosocomial infections. Our objectives were to determine the prevalence of malnutrition after 1 week of hospitalization in acute stroke and to establish its relation to the stress response and neurological outcome.

METHODS

The study included 104 patients with an acute stroke of less than 24 hours' duration. Nutritional parameters (triceps skinfold thickness, midarm muscle circumference, serum albumin, and calorimetry) were evaluated at admission and after 1 week. Stress response (free urinary cortisol) was measured daily during the first week. Neurological deficit was evaluated by the Canadian Stroke Scale. Clinical outcome was estimated by the Barthel Index 1 month after the acute stroke. Patients received an oral standard diet or polymeric enteral nutrition when they had swallowing difficulties.

RESULTS

Protein-energy malnutrition was observed in 16.3% of patients at inclusion and in 26.4% after the first week, with a significant decrease in fat (P = .002) and visceral protein compartments (P = .049). Malnourished patients showed higher stress reaction and increased frequency of infections and bedsores in comparison with the appropriately nourished group. Multiple logistic regression analysis showed that malnutrition after 1 week (odds ratio, 3.5; 95% confidence interval, 1.2 to 10.2) and elevated free urinary cortisol (odds ratio, 3.3; confidence interval, 1.05 to 10.2) increased the risk of poor outcome (death or Barthel Index < or = 50 on the 30th day of follow-up) independently of age and nutritional status at admission.

CONCLUSIONS

Our findings suggest that protein-energy malnutrition after acute stroke is a risk factor for poor outcome. Early appropriate enteral caloric feeding did not prevent malnutrition during the first week of hospitalization.

Loss of upper respiratory tract immunity with parenteral feeding

OBJECTIVE

The authors examine the effect of route and type of nutrition on an established upper respiratory tract immunity and investigate potential mechanisms for increased pneumonia rates in critically injured patients fed parenterally.

SUMMARY BACKGROUND DATA

The primary immunologic defense against many mucosal infections is IgA. Prior work shows that mice fed total parenteral nutrition (TPN) solutions either intravenously or intragastrically had small intestinal gut-associated lymphoid tissue (GALT) atrophy along with decreased intestinal IgA compared with animals fed complex enteral diets. The small intestine is postulated to be the origin of most mucosal immunity, both intraintestinal and extraintestinal. The impact of diets affecting GALT, small intestine IgA, and upper respiratory tract immunity is studied.

METHODS

Male Institute of Cancer Research mice underwent intranasal inoculation with a mouse-specific influenza virus to establish immunity. Three weeks later, the mice were randomized to chow, intragastric Nutren (Clintec, Chicago, IL), intravenous TPN, or intragastric TPN. After 5 days of feeding, mice were challenged with intranasal virus and killed at 40 hours to determine viral shedding from the upper respiratory tract.

RESULTS

Despite similar body weights, there was significant atrophy in the Peyer's patch cells from animals fed the TPN solution intravenously or intragastrically. There was no viral shedding in any animal fed via the gastrointestinal tract, whereas 5 of 10 animals fed intravenous TPN had continued viral shedding.

CONCLUSIONS

The IgA-dependent upper respiratory tract immunity was preserved with enteral feeding but not with intravenous feeding. Upper respiratory tract immunity is not dependent on intestinal GALT mass but is influenced by route of nutrition. The underlying mechanisms may explain the higher pneumonia rate in critically injured patients fed parenterally.

A proposed revision of current ICD-9-CM malnutrition code definitions

Protein-energy malnutrition (PEM) is as common today in adult medical and surgical patients as it was when it was first identified more than 25 years ago. Under the current diagnosis-related group (DRG) payment system, malnutrition is considered a comorbidity or complicating condition. Thus, the identification and coding of malnutrition through the use of the International Classification of Diseases, ninth edition, Clinical Modification (ICD-9-CM) malnutrition codes can potentially change a patient's DRG and subsequently increase the amount of reimbursement a hospital receives. Unfortunately, the definitions for the current ICD-9-CM malnutrition diagnosis codes were developed principally in relation to clinical syndromes of primary PEM seen in pediatric age groups in less developed countries, rather than in relation to syndromes seen in hospitalized adult patients in industrialized societies. This discrepancy often leads to confusion and inconsistency when institutions attempt to code adult patients for malnutrition. Furthermore, inaccurate coding can result in inadequate reimbursement or rejection of a claim. Clearly, a separate description of the different forms of PEM seen in adults is needed not only for optimal application of nutrition support therapies but also for accurate medical records, quality assurance procedures, and reimbursement purposes. On the basis of 20 years of experience providing nutrition support to hospitalized adult patients, this article presents a schema developed at the Deaconess Hospital (Boston,Mass) that attempts to better define adult PEM using the ICD-9-CM malnutrition codes. The purpose of this article is to foster discussion and ultimately promote general agreement about a definition of adult PEM.

Motility agents for the placement of weighted and unweighted feeding tubes in critically ill patients

OBJECTIVE

To determine if successful attempts at feeding tube placement into the small bowel could be increased with the use of a weighted end or by pre-treatment with a drug to increase gastric motility.

DESIGN

A prospective randomized control study, double blinded for a drug study drug, in a population of critically ill patients.

SETTING

A 635-bed acute care hospital in Philadelphia, Pennsylvania.

PATIENTS

Eighty-three patients in the critical care setting randomized into four groups receiving either parenteral normal saline (NS) 100 cc, erythromycin (EMY) 200 mg, or metoclopramide (MET), 10 mg, 30 min prior to attempted tube placement with either a weighted (WEI) (57 patients) or unweighted tube (UNW) (26 patients).

RESULTS

When analyzed for number of attempts prior to successful tube placement into the stomach there was a significant difference between the unweighted and weighted groups: 2.08 +/- 1.03 attempts vs 1.51 +/- 0.94, P < or = 0.015. Duodenal migration at 24 h was demonstrated in three patients in the NS/UNW group and in two patients in the NS/WEI group as compared to no patients in either the EMY/WEI or the MET/WEI groups (p < or = 0.025, Fisher's exact test).

CONCLUSIONS

These data demonstrate that the use of weighted feeding tubes decreases the number of attempts required to achieve gastric intubation, but that motility agents given prior to tube insertion do not augment advancement of the feeding tube beyond the stomach and may in fact hinder placement into the duodenum.

Malnutrition and clinical outcomes: the case for medical nutrition therapy

Malnutrition is not a new or a rare problem. In studies involving more than 1,327 hospitalized adult patients, 40% to 55% were found to be either malnourished or at risk for malnutrition, and up to 12% were severely malnourished. Surgical patients with likelihood of malnutrition are two to three times more likely to have minor and major complications as well as increased mortality; and their length of stay can be extended by 90% compared with the stay of well-nourished patients. Hospital charges are reported to be from 35% to 75% higher for malnourished patients than for well-nourished patients. Obtaining data to assess the nutritional status of patients is essential to optimal patient care, especially for patients at high risk for malnutrition. Nutrition assessment can be done with readily available and relatively inexpensive methods. But it is not enough to assess and identify malnutrition. Outcomes are improved and costs are saved only when appropriate intervention follows. This article identifies many well-conducted, published studies that support the findings that health outcomes of malnourished patients can be improved and that overall use of resources can be reduced by nutrition counseling, oral diet and oral supplements, enteral formula delivered via tube, and parenteral nutrition support via central or peripheral line. Early nutrition assessment and appropriate nutrition intervention must be accepted as essential for the delivery of quality health care. Appropriately selected nutrition support can address the problem of malnutrition, improve clinical outcomes, and help reduce the costs of health care.

Early enteral feeding in postsurgical cancer patients. Fish oil structured lipid-based polymeric formula versus a standard polymeric formula

OBJECTIVES

The authors compared the safety, gastrointestinal tolerance, and clinical efficacy of feeding an enteral diet containing a fish oil/medium-chain triglyceride structured lipid (FOSL-HN) versus an isonitrogenous, isocaloric formula (O-HN) in patients undergoing major abdominal surgery for upper gastrointestinal malignancies.

SUMMARY BACKGROUND DATA

Previous studies suggest that feeding with n-3 fatty acids from fish oil can alter eicosanoid and cytokine production, yielding an improved immunocompetence and a reduced inflammatory response to injury. The use of n-3 fatty acids as a structured lipid can improve long-chain fatty acid absorption.

METHODS

This prospective, blinded, randomized trial was conducted in 50 adult patients who were jejunally fed either FOSL-HN or O-HN for 7 days. Serum chemistries, hematology, urinalysis, gastrointestinal complications, liver and renal function, plasma and erythrocyte fatty acid analysis, urinary prostaglandins, and outcome parameters were measured at baseline and on day 7. Comparisons were made in 18 and 17 evaluable patients based a priori on the ability to reach a tube feeding rate of 40 mL/hour.

RESULTS

Patients receiving FOSL-HN experienced no untoward side effects, significant incorporation of eicosapentaenoic acid into plasma and erythrocyte phospholipids, and a 50% decline in the total number of gastrointestinal complications and infections compared with patients given O-HN. The data strongly suggest improved liver and renal function during the postoperative period in the FOSL-HN group.

CONCLUSION

Early enteral feeding with FOSL-HN was safe and well tolerated. Results suggest that the use of such a formula during the postoperative period may reduce the number of infections and gastrointestinal complications per patient, as well as improve renal and liver function through modulation of urinary prostaglandin levels. Additional clinical trials to fully quantify clinical benefits and optimize nutritional support with FOSL-HN should be undertaken.

Econutrition and health maintenance — A new concept to prevent GI inflammation, ulceration and sepsis

The nutritional needs of the gastrointestinal mucosa per se has until today been largely neglected. It is a rather novel finding, that the lower part of the digestive tract is most dependent on luminal nutrition for maintaining its integrity, structure and function. Even the most complete parenteral nutrition (PN) regimen cannot, in the absence of adequate enteral nutrition (EN), fully prevent the development of mucosal atrophy in the lower part of the digestive tract, especially the colon. Nor can PN prevent the downregulation of the colon's many important functions. Increased microbial translocation and a predisposition to sepsis are consequences of inadequate luminal nutrition. Such developments can only be prevented by oral feeding and the local 'manufacturing' of essential nutrients in the colon. Probiotic bacteria are also important, especially with respect to the function of the colonic mucosa, which is the focus of this review.

Perioperative nutritional support in patients undergoing hepatectomy for hepatocellular carcinoma

This prospective, randomized, controlled trial from the University of Hong Kong evaluated the efficacy of perioperative parenteral nutrition (PN) in patients requiring hepatectomy for primary hepatocellular carcinoma. From September 1990 through June 1993, 150 consecutive patients with resectable hepatocellular carcinoma were randomly assigned to receive either perioperative PN (n = 75), in addition to usual oral diet, or to no additional therapy (oral diet alone without PN; n = 75). Excluding patients with metastatic disease, a total of 64 patients in the perioperative PN group (39 with associated cirrhosis, 18 with chronic active hepatitis, and 7 without associated liver disease) were compared to 60 control patients (33 with cirrhosis, 12 with chronic active hepatitis and 15 with no associated liver disease). PN was started 7 days before hepatic resection and continued for 7 days after operation in the experimental patients. The PN consisted of standard micronutrients, dextrose, lipid emulsion (containing 50 percent of lipid as medium-chain triglycerides, MCT) and amino acids enriched in branched-chain amino acids (BCAA, 35 percent of PN protein intake), and provided = 1.5 g protein/kg/day and 30 kcal/kg/day. PN was administered via a superior vena cava Broviac catheter cycled over 12 hours each evening preoperatively, and as a 24 hour infusion during the postoperative week. Control patients received only 5 percent dextrose in normal saline postoperatively, with volume and sodium content similar to the experimental PN-treated patients. All patients studied (experimental and control) received 25 grams of albumin intravenously for 5 days postoperatively, and all were allowed to consume enteral diet as tolerated throughout the entire study period. Preoperative assessment included standard anthropometric indices, serum chemistries and proteins, indocyanine green clearance (an index of hepatic function), hand grip strength, and immune function tests (serum immunoglobulin concentrations and peripheral lymphocyte stimulation by phytohemagglutinin). Postoperative assessment included the same preoperative indices (chemistries measured from days 1 to 8 post-operatively), and overall postoperative mortality and morbidity during the hospitalization. Morbidity indices included both infectious complications and non-infectious complications (eg, pleural effusion, ascites, renal failure, hepatic coma). The two groups of patients were similar in age, sex, total and percent weight loss, hepatic carcinoma stage, incidence of cirrhosis, and other preoperative indices. However, a higher percentage of patients in the PN group had abnormal preoperative hepatic function by indocyanine green clearance (67 vs 47%, p = 0.03). The proportion undergoing major hepatectomy and other important intraoperative factors were similar between groups. No significant difference in postoperative hospital mortality occurred between groups (PN 8% vs control 15%; p = 0.30), and PN use did not change hand-grip strength, skin-fold thickness or midarm circumference. However, a significant beneficial effect of PN on hospital morbidity was observed Perioperative PN use was associated with a significant reduction in the overall postoperative morbidity rate (PN group 34% vs control group 55%; p = 0.02). This difference was mainly due to a significant reduction in infectious complications (PN 17% vs control 37%; p = 0.01), and in the need for diuretic drugs to control ascites (PN 25% vs control 50%; p = 0.004). There were no differences between groups in serum immunoglobulins or lymphocyte response to mitogens. There was less deterioration of liver function with PN as measured by the change in the rate of indocyanine green clearance (PN group -2.8% loss vs control group -4.8% loss; p = 0.05). The attenuation of hepatic function loss with PN occurred despite a significant rise in serum transaminase values from days 5 to 8 postoperatively. PN therapy was also associated with le

Route of nutritional supply influences local, systemic, and remote organ responses to intraperitoneal bacterial challenge

OBJECTIVE

The authors' aim was to investigate whether antecedent nutritional routes influence immune responses after surgical insult.

SUMMARY BACKGROUND DATA

Total parenteral nutrition (TPN) may influence host responses to infection. To the best of the authors' knowledge, however, no study has focused on the mechanisms underlying the influence of nutritional route on local, systemic, and remote organ (lung) responses after surgical insult.

METHODS

Sixty-eight rats were divided into TPN and total enteral nutrition (TEN) groups. The two groups received identical nutrients for 7 days and were then challenged intraperitoneally with 3 x 10(8) Escherichia coli. In the first experiment, the rats were observed for survival. In the second experiment, the rats were killed before (0 hours) challenge or 2 or 6 hours after challenge. Peritoneal exudative cells (PEC) and bronchoalveolar cells (BALC) were harvested and cultured in vitro. Colony-forming units of bacteria in the peritoneal lavage fluid (PLF) were determined. Tumor necrosis factor (TNF), interleukin-1 alpha (IL-1 alpha), interferon-gamma (IFN-gamma) levels in serum, PLF, bronchoalveolar lavage fluid (BALF), and cell culture supernatants were measured.

RESULTS

The 48-hour survival rate was higher in TEN than in TPN rats. Local immunity was depressed in the TPN group. Bacterial colony counts in PLF were significantly higher in the TPN group than in the TEN group after challenge. The number of PECs was significantly lower, and at 2 hours, local cytokine (TNF and IL-1 alpha) responses were diminished in the TPN group compared with the TEN group at 2 hours. The number of PECs showed a significant positive correlation with levels of local cytokines in the TEN group but not in the TPN group. Elevation of local IFN-gamma was significant from 0 to 6 hours in the TEN group but not in the TPN group. In vitro production of TNF by PEC was impaired in the TPN rats before challenge. Remote organ (lung) responses were suppressed in the TPN group. The number of BALCs and the TNF levels in BALF declined significantly between 0 and 2 hours in the TEN group but not in the TPN group. Interferon-gamma levels in BALF were higher in the TEN group than in the TPN group at 2 hours. Systemic cytokine responses were disturbed in the TPN group. Production of systemic TNF was greater, but the IFN-gamma response was diminished in the TPN group compared with the TEN group after intraperitoneal bacterial challenge.

CONCLUSION

Local, systemic, and remote organ (lung) immune responses to intraperitoneal bacterial challenge are suppressed in TPN-treated animals, leading to poor survival after challenge. Enteral nutrition before surgical insult may enhance host immune responses after the insult as compared to parenteral nutrition.

The enhanced effect of parenteral nutrition on hepatotoxicity

Recent studies have demonstrated that enteral feedings are associated with decreased morbidity and mortality when compared with parenteral feedings. In this study, we hypothesized that (1) route of feeding affects morbidity and mortality in a model of drug-induced hepatotoxicity and (2) glutamine and polymyxin B, which have been reported to reduce bacterial translocation, attenuate this effect when TPN is used. Male virus-free Wistar rats were divided into six groups receiving: (1) ad libitum chow infused with intravenous (IV) saline (Chow), (2) standard total parenteral nutrition solution administered via gastrostomy (Enteral), (3) standard total parenteral nutrition infused via a central catheter (TPN), (4) standard TPN containing polymyxin B (TPN-PolyB), and (5) glutamine-enriched TPN (TPN-GLN). A final group of animals was not manipulated but harvested at time 0 to serve as controls. The dose of polymyxin B used in this study has previously been shown to significantly reduce bacterial translocation. After 4 d of feeding, all rats received 5% dextrose infusion after an intraperitoneal (IP) injection of acetaminophen (ACM). Rats were sacrificed 0, 6, and 24 h after ACM administration. The TPN group had a lower liver glutathione level after 6 and 24 h, greater levels of liver enzymes after 24 h, and a lower survival rate after 24 h compared with Chow. The Enteral group had less morbidity than TPN but greater morbidity than Chow. Addition of polymyxin B or glutamine had a minimal effect on morbidity or mortality when compared to the TPN group. We conclude that rats receiving IV nutrition have greater morbidity and mortality following a standard hepatic insult than chow-fed rats. We speculate that alteration of microsomal cytochrome P-450 or drug clearance may be related to the benefits of providing nutrients by the gastrointestinal route.

Complications of needle catheter jejunostomy in 2,022 consecutive applications

BACKGROUND

We commonly use needle catheter jejunostomy (NCJ) for early enteral feeding in selected patients. Review of our approach was prompted by the suggestion that enteral feeding represents a "stress test" for the bowel and may be associated with a high complication rate.

MATERIALS AND METHODS

We reviewed patients with NCJ inserted over the past 16 years by prospective database, chart review, and conference minutes, with emphasis on complications.

RESULTS

During the conduct of 28,121 laparotomies, 2,022 NCJs inserted in 1,938 patients (7.2%) resulted in 34 NCJ-related complications in 29 patients (1.5%) The most common complication was premature loss of the catheter from occlusion or dislodgment (n = 15; 0.74%), and the most serious was bowel necrosis (n = 3; 0.15%).

CONCLUSIONS

Needle catheter jejunostomy may be inserted and used with a low complication rate. Most complications were preventable through greater attention to detail and better monitoring of physical examination of patients with marginal gut function.

Enteral nutritional support in acute alcoholic pancreatitis

BACKGROUND

The experience to date with total enteral nutritional (TEN) support in acute alcoholic pancreatitis patients admitted to the University of Kentucky affiliated hospitals was reviewed.

METHODS

Standard enteral formulas sufficient to meet patient's needs were administered into the small bowel via endoscopically placed nasoenteric feeding tubes in five patients. Feedings were administered for a mean of 28.4 days. Pancreatitis was mild to moderate in severity by Ranson's criteria in four patients, and severe in one.

RESULTS

Four patients developed complications of pancreatitis before initiation of TEN, representing the most common indication for nutritional support. Nutritional status was maintained by TEN with no significant complications from this nutritional support identified. Diarrhea that did not limit tube feeding developed in a single patient.

CONCLUSIONS

This experience further supports the safety of TEN in acute pancreatitis and suggests that adequate nutritional support can be delivered by this route.

The need for aggressive nutritional intervention in the injured patient: the development of a predictive model

Early nutritional intervention has been advocated in trauma patients. We have developed a model to identify those patients who will most benefit from the invasive and costly measures that are required to provide injured patients with early enteral feedings. Four hundred forty-two patients admitted to a level I trauma center during a 2-month period were evaluated using 21 clinical variables. Time to tolerance of a regular diet was used as the dependent variable in a step-wise regression, and then the selected variables were used to build a classification and regression tree to predict tolerance of a regular diet within 5 days. Our findings demonstrate that intensive care unit disposition, Injury Severity Score, Abdominal Trauma Index, and the need for early surgical intervention are important predictors regarding the need for early nutritional intervention. When the model was applied to the study population, it had a sensitivity of 83%, a specificity of 84%, and an accuracy of 84%.

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

Concerns have recently been expressed at suggestions that postoperative sepsis may be more common in patients who have received preoperative total parenteral nutrition (TPN). The mechanism suggested for this is that TPN causes intestinal mucosal atrophy leading to increased bacterial translocation from the gut as a source of systemic sepsis. This hypothesis was examined in 203 patients who had an elective laparotomy, 28 of whom required at least 10 days of preoperative TPN. Neither mucosal atrophy nor bacterial translocation was more common in parenterally fed patients than in enterally fed controls. In humans theoretical concerns about the adverse effects of TPN on intestinal integrity are unfounded.

Early enteral nutrition support in patients undergoing liver transplantation

BACKGROUND

The purpose of this study was to determine the effects of early postoperative tube feeding on outcomes of liver transplant recipients.

METHODS

Fifty transplant patients were randomized prospectively to receive enteral formula via nasointestinal feeding tubes (tube-feeding [TF] group) or maintenance i.v. fluid until oral diets were initiated (control group). Thirty-one patients completed the study. Resting energy expenditure, nitrogen balance, and grip strength were measured on days 2, 4, 7, and 12 after liver transplantation. Calorie and protein intakes were calculated for 12 days posttransplant.

RESULTS

Tube feeding was tolerated in the TF group (n = 14). The TF patients had greater cumulative 12-day nutrient intakes (22,464 +/- 3554 kcal, 927 +/- 122 g protein) than did the control patients (15,474 +/- 5265 kcal, 637 +/- 248 g protein) (p < .002). Nitrogen balance was better in the TF group on posttransplant day 4 than in the control group (p < .03). There was a rise in the overall mean resting energy expenditure in the first two posttransplant weeks from 1487 +/- 338 to 1990 +/- 367 kcal (p = .0002). Viral infections occurred in 17.7% of control patients compared with 0% of TF patients (p = .05). Although other infections tended to occur more frequently in the control group vs the TF group (bacterial, 29.4% vs 14.3%; overall infections, 47.1% vs 21.4%), these differences were not statistically significant. Early posttransplant tube feeding did not influence hospitalization costs, hours on the ventilator, lengths of stay in the intensive care unit and hospital, rehospitalizations, or rejection during the first 21 posttransplant days.

CONCLUSIONS

Early posttransplant tube feeding was tolerated and promoted improvements in some outcomes and should be considered for all liver transplant patients.

Early nutrition support modifies immune function in patients sustaining severe head injury

BACKGROUND

Immunosuppression after severe head injury has been characterized by a depressed CD4 (T-helper/inducer)-CD8 (T-suppressor/cytotoxic) ratio and decreased T-lymphocyte responsiveness. Some investigators propose that this immunocompromized state is the result of an injury-associated hypermetabolic response and inadequate nutrient delivery during the immediate postinjury recovery phase. Previous observations from our institution demonstrated a preserved CD4-CD8 ratio in severe closed-head injury (CHI) patients receiving early parenteral nutrition (PN). It was unclear whether early PN or other aspects of patient care eliminated the characteristic depression in cellular immunity. The purpose of this study was to further investigate the effect of early PN on the immune function of CHI patients.

METHODS

Nine patients sustaining severe CHI were prospectively randomized to either early PN (n = 4) at day 1 or delayed PN (n = 5) at day 5. Total nutrient administration was delivered at 2 g of protein/kg per day and 40 nonprotein kcal/kg per day for at least the first 14 days of hospitalization. Analysis for T-lymphocyte expression of CD4 and CD8 cell surface antigens and interleukin-6 was performed on days 1, 3, 7, and 14 of hospitalization. T-lymphocyte activation in response to stimulation by concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogens (PWM) was also assessed on these days.

RESULTS

Significant increases in total CD4 cell counts (2048 +/- 194 to 2809 +/- 129 vs 1728 +/- 347 to 1825 +/- 563, p < .05) and CD4% (42.6 +/- 4.4% to 56.2 +/- 2.6% vs 36.6 +/- 6.6% to 36.6 +/- 11.3%, p < .05) were observed at day 14 in patients receiving early vs delayed PN. An improved lymphocyte response from baseline to day 14 after Con A stimulation was demonstrated in the early PN group (3850 +/- 1596 to 16144 +/- 5024 cpm, p < .05). A significant rise in the CD4-CD8 ratio over baseline to day 14 was also noted in the early PN group (1.43 +/- 0.17 to 2.38 +/- 0.54, p < .05).

CONCLUSIONS

The early aggressive nutrition support of CHI patients appears to modify immunologic function by increasing CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A.

Effects of parenteral and enteral nutrition on gut-associated lymphoid tissue

Changes in mucosal defense have been implicated as important factors affecting infections complications in critically ill patients. To study the effects of nutrient administration on gut-associated lymphatic tissue (GALT), ICR mice were randomized to receive chow plus intravenous saline, intravenous feeding of a total parenteral nutrition (TPN) solution, or enteral feeding of the same TPN solution. In a second series of experiments, a more complex enteral diet (Nutren) was compared with chow feeding and enteral TPN. After 5 days of feeding with experimental diets, lymphocytes were harvested from the mesenteric lymph nodes (MLNs), Peyer's patches (PPs), lamina propria (LP) cells, and intraepithelial (IE) spaces of the small intestine to determine cell yields and phenotypes. Small intestinal washings, gallbladder contents, and sera were collected and analyzed for immunoglobulin A (IgA) levels. In both series of experiments, there were no significant changes within the MLNs. There were significant decreases in total cell yields from the PPs, IE spaces, and LP in animals fed with TPN solution, either enterally or parenterally, as compared with chow-fed mice. Total T cells were decreased in both TPN-fed groups in the PPs and LP, whereas total B cells were decreased in the PP, IE, and LP populations. Total cell numbers remained normal in the Nutrenfed group, except for a decrease in LP T cells. CD4+ LP cells decreased significantly with a reduction in the CD4/CD8 ratio in mice fed TPN solution either intravenously or enterally, whereas IgA recovery from small intestinal washings was significantly decreased in the same groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Enteral nutrition in the critically ill patient: a prospective survey

OBJECTIVES

To describe current enteral nutrition-prescribing practices for critically ill patients, and to identify factors associated with initiation of, and tolerance to, enteral nutrition.

DESIGN

A prospective, cohort study.

SETTING

Two tertiary care medical-surgical intensive care units (ICU) in Ontario, Canada.

PATIENTS

We enrolled 99 consecutive patients who were expected to stay in the ICU for > 3 days and who were unable to tolerate oral nutrition. We followed patients for 21 days or until they tolerated enteral nutrition, tolerated oral nutrition, were discharged from the ICU, or died.

MEASUREMENTS AND MAIN RESULTS

We recorded time elapsed from ICU admission to initiation and tolerance of enteral feedings, and examined factors associated with these events. We defined tolerance as receiving 90% of estimated daily energy requirements for > 48 hrs without gastrointestinal dysfunction (i.e., high gastric residuals, vomiting, diarrhea, abdominal distention). Seventy-three (74%) of 99 patients were started on enteral feedings an average 3.1 days (range 1 to 18) after ICU admission. Of 26 patients never started on enteral nutrition, three (12.5%) patients eventually tolerated oral nutrition, 14 (54.0%) patients were discharged from the ICU, and seven (27.0%) patients died. Reasons for not initiating enteral nutrition included absence of bowel sounds (27.0%), high nasogastric drainage (16.9%), contraindication to enteral nutrition (16.7%), tolerance of oral nutrition (6.8%), and no apparent reason (5.1%). Abdominal surgery, use of vasoactive drugs, and admission to one hospital made initiation of enteral nutrition less likely, whereas presence of bowel sounds and admission to the other hospital made initiation of enteral nutrition more likely. Thirty-five (42.9%) of 73 patients started on enteral nutrition achieved tolerance of the regimen. The average time from ICU admission to tolerance of feedings was 5.8 days (range 1 to 14). Once started on enteral nutrition, the most common reasons for decreasing or discontinuing feedings included high gastric residuals (51.0%), mechanical feeding tube problems (15.4%), medical or surgical procedures (5.4%), and vomiting (5.1%). Use of paralytic agents and the presence of high gastric residuals were associated with intolerance. Of 38 patients who did not achieve tolerance, 20 (52.6%) patients were discharged from the ICU, eight (21.0%) patients died, and eight (21.0%) patients eventually tolerated oral nutrition.

CONCLUSIONS

Enteral nutrition is not started in all eligible ICU patients. Approximately half of those patients receiving enteral nutrition achieved tolerance of the regimen. Gastrointestinal dysfunction causing intolerance to enteral nutrition is a common reason for not starting, or discontinuing, feedings.

Intraoperative placement of the nasoenteric feeding tube: a practical alternative?

BACKGROUND

The provision of early postoperative enteral feeding may be enhanced by the placement of enteral feeding access during celiotomy, but surgeons are often reluctant to pursue this option because of the extra effort required.

METHODS

We conducted a retrospective review of our 2-year experience with 60 sequential intraoperative nasoenteric feeding-tube placements and included data on demographics, diagnosis, surgery, type of feeding tube, formula, tolerance, and complications. Our surgeons placed intraoperative nasoenteric feeding tubes at their discretion in a variety of subjects who were undergoing elective or urgent celiotomies.

RESULTS

The surgeries largely involved the upper gastrointestinal tract, and feeding-tube placements were readily accomplished. The majority of patients received enteral feedings within 3 postoperative days and achieved feeding rates of 50 mL/h or greater. The average duration of feeding-tube use was 1 week, accounting for 399 feeding days overall. There were no serious complications attributable to feeding-tube placement or use, but inadvertent tube removal by patients or staff was a limitation.

CONCLUSIONS

Intraoperative placement of the nasoenteric feeding tube may be a reasonable option for treating the surgical patient at nutritional risk who faces a limited course of impaired oral intake postoperatively.

Percutaneous endoscopic gastrojejunostomy: a dual center safety and efficacy trial

Although jejunal tube placement through a percutaneous endoscopic gastrostomy (PEG) has not been proven to be preferable to PEG feeding, it would be theoretically advantageous for those patients prone to gastrointestinal aspiration. However, reliable placement of a small bowel feeding tube through a PEG has been technically difficult. We have previously reported successful placement of a percutaneous endoscopic gastrojejunostomy (PEG/J) with minimal complications. These results are in contrast to other series that report technical difficulty, frequent tube dysfunction and gastric aspiration. We describe an over-the-wire PEG/J technique performed by multiple operators at two medical centers. Gastrostomy tube placement was successful in 94% of patients. Initial placement of the jejunal tube was successful in 88% of patients. Second attempts were 100% successful. The average procedure time was 36 minutes. The distal duodenal and jejunal placement of the jejunal tube resulted in no episodes of gastroduodenal reflux. Complications included jejunal tube migration (6%), clogging (18%), and unintentional removal (11%). The majority of patients were ultimately converted to either oral or intragastric feedings. We conclude that the PEG/J system is a reliable, reproducible method of small bowel feeding and is associated with no episodes of tube feeding reflux when the jejunal tube is positioned in the distal duodenum or beyond. Furthermore, it provides a temporary nutritional bridge for those patients who are later transitioned to either PEG or oral feeding.

Enteral nutrition during multimodality therapy in upper gastrointestinal cancer patients

OBJECTIVE

The objective of this study was to evaluate long-term enteral nutrition support in postoperative cancer patients.

BACKGROUND

Multimodality therapy for surgical patients with upper gastrointestinal malignancies may improve survival, but often results in substantial malnutrition, immunosuppression, and morbidity. The benefits of combined inpatient and outpatient enteral feeding with standard diets or diets supplemented with arginine, RNA + omega-3 fatty acids are unclear.

METHODS

Sixty adult patients with esophageal (22), gastric (16), and pancreatic (22) lesions were stratified by disease site and percent usual weight and randomized to receive supplemental or standard diet via jejunostomy beginning on the first postoperative day (goal = 25 kcal/kg/day) until hospital discharge. Patients also were randomized to receive (n = 37) or not receive (n = 23) enteral jejunostomy feedings (1000 kcal/day overnight) for the 12- to 16-week recovery and radiation/chemotherapy periods. Plasma and peripheral white blood cells were obtained for fatty acid levels and PGE2 production measurements.

RESULTS

Mean plasma and cellular omega 3/omega 6 fatty acid levels (percent composition) increased significantly (p < 0.05) in the arginine + omega-3 fatty acid group by postoperative day 7 (0.30 vs. 0.13) and (0.29 vs. 0.14) and continued to increase over time. Mean PGE2 production decreased significantly (p < 0.05) from 2760 to 1600 ng/10(6) cells/mL at day 7 in the arginine + omega-3 fatty acid group, whereas no significant change over time was noted in the standard group. Infectious/wound complications occurred in 10% of the supplemented group compared with 43% of the standard group (p < 0.05); mean length of hospital stay was 16 vs. 22 (p < 0.05) days, respectively. Of the patients who received postoperative chemoradiation therapy, only 1 (6%) of the 18 patients randomized to receive tube feeding did not continue, whereas 8 (61%) of the 13 patients not randomized to tube feedings required crossover to jejunostomy nutritional support.

CONCLUSIONS

Supplemental enteral feeding significantly increased plasma and peripheral white blood cell omega 3/omega 6 ratios and significantly decreased PGE2 production and postoperative infectious/wound complications compared with standard enteral feeding. For outpatients receiving adjuvant therapy, those initially randomized to oral feedings alone required rehospitalization more frequently, and 61% crossed over to supplemental enteral feedings.

Insertion of a transpyloric feeding tube during laparotomy in the critically injured: rationale and plea for routine use

Although clinical and experimental evidence favours early enteral feeding in the critically injured, provision of such enteral feeds can be difficult. Gastric feeds are often not tolerated and may lead to aspiration. An intolerance of gastric feeds leads to a cumulative energy and protein deficit and may result in the initiation of expensive parenteral nutrition (TPN). An alternative and under-utilized technique to ensure enteral access in trauma victims is the insertion of a transpyloric (nasojejunal) feeding tube during emergent laparotomy. We have employed this method of enteral access with success. In the following report, we describe this technique, provide an illustrative case with a cost comparison between nasojejunal feeds and TPN, present the rationale for such a mode of enteral access and outline the indications and contraindications. Enteral access by the intra-operative insertion of a transpyloric feeding tube allows immediate/early enteral feeding that is easy, safe, reliable and inexpensive.

Evolving concepts in the pathogenesis of postinjury multiple organ failure

Early epidemiologic studies concluded that infection with systemic sepsis was the common pathway for the development of ARDS and eventual MOF. As a consequence, research investigation from 1977 to 1987 focused on later clinical events (e.g., immunosuppression, persistent hypercatabolism, and bacterial translocation). Now, it is believed that an initial massive traumatic insult can create severe SIRS independent of infection (one-hit model). Alternatively, a less severe traumatic insult can create an inflammatory environment (i.e., primes the host) such that a later, otherwise innocuous, secondary inflammatory insult precipitates severe SIRS (two-hit model). As a result of these newer inflammatory models, research interest during the last 5 years has shifted to investigating earlier clinical events (e.g., unrecognized flow-dependent oxygen consumption, ischemia/reperfusion, and priming/activation of the inflammatory response).

Bacterial translocation and enteral nutrition in humans: an outsider looks in

PURPOSE

To assess the literature documenting the existence of bacterial translocation in humans, the effects of enteral nutrition on bacterial translocation in humans, and the hypothesis that enteral nutrition prevents bacterial translocation in humans.

DATA IDENTIFICATION

Sources included Medline search, references from review articles, and references from animal and human studies.

STUDY SELECTION

The goal was to include all animal and human studies directly addressing questions of bacterial translocation and nutritional status or nutritional support.

DATA EXTRACTION

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

RESULTS OF DATA SYNTHESIS

Bacterial translocation is a well documented phenomenon in animal models. Starvation and malnutrition of themselves do not induce bacterial translocation, but may facilitate translocation in the presence of other systemic insults. Parenteral nutrition and many forms of enteral nutrition may induce and/or facilitate bacterial translocation. Chow and certain fiber sources seem protective. Moderate direct and several lines of indirect evidence support the existence of bacterial translocation in humans. There is no direct evidence and questionable indirect evidence suggesting that enteral nutrition prevents or modifies bacterial translocation in humans.

CONCLUSIONS

The hypothesis relating enteral nutrition and bacterial translocation in critically ill patients remains attractive, but unproven.

Early enteral administration of a formula (Impact) supplemented with arginine, nucleotides, and fish oil in intensive care unit patients: results of a multicenter, prospective, randomized, clinical trial

OBJECTIVE

To determine if early enteral feeding, in an intensive care unit (ICU) patient population, using a formula supplemented with arginine, dietary nucleotides, and fish oil (Impact), results in a shorter hospital stay and a reduced frequency of infectious complications, when compared with feeding a common use enteral formula (Osmolite.HN).

DESIGN

A prospective, randomized, double-blind, multicenter trial.

SETTING

ICUs in eight different hospitals.

PATIENTS

Of 326 patients enrolled in the study, 296 patients were eligible for analysis. They were admitted to the ICU after an event such as trauma, surgery, or sepsis, and met a risk assessment screen (Acute Physiology and Chronic Health Evaluation II [APACHE II] score of > or = 10, or a Therapeutic Intervention Scoring System score of > or = 20) and study eligibility requirements. Patients were stratified by age (< 60 or > or = 60 yrs of age) and disease (septic or systemic inflammatory response syndrome).

INTERVENTIONS

Patients were enrolled and full-strength tube feedings were initiated within 48 hrs of the study entry event. Enteral feedings were advanced to a target volume of 60 mL/hr by 96 hrs of the event. One hundred sixty-eight patients were randomized to receive the experimental formula, and 158 patients were randomized to receive the common use control formula.

MEASUREMENTS AND MAIN RESULTS

Both groups tolerated early enteral feeding well, and the frequency of tube feeding-related complications was low. There were no significant differences in nitrogen balance between groups on study days 4 and 7. Patients receiving the experimental formula had a significant (p = .0001) increase in plasma arginine and ornithine concentrations by study day 7. Plasma fatty acid profiles demonstrated higher concentrations of linoleic acid (p < .01) in the patients receiving the common use formula and higher concentrations of eicosapentaenoic and docosahexaenoic acid (p < .01) in the patients receiving the experimental formula. The mortality rate was not different between the groups and was significantly (p < .001) lower than predicted by the admission severity scores in both feeding groups. In patients who received at least 821 mL/day of the experimental formula, the hospital median length of stay was reduced by 8 days (p < .05). In patients stratified as septic, the median length of hospital stay was reduced by 10 days (p < .05), along with a major reduction in the frequency of acquired infections (p < .01) in the patients who received the experimental formula. In the septic subgroup fed at least 821 mL/day, the median length of stay was reduced by 11.5 days, along with a major reduction in acquired infections (both p < .05) in the patients who received the experimental formula.

CONCLUSIONS

Early enteral feeding of the experimental formula was safe and well tolerated in ICU patients. In patients who received the experimental formula, particularly if they were septic on admission to the study, a substantial reduction in hospital length of stay was observed, along with a significant reduction in the frequency of acquired infections.

Elemental diet and IV-TPN-induced bacterial translocation is associated with loss of intestinal mucosal barrier function against bacteria

OBJECTIVE

The goal of the current study was to directly assess the role of loss of mucosal barrier function in nutritionally induced bacterial translocation.

BACKGROUND

Parenteral and certain elemental enteral diets have been shown to promote bacterial translocation. The mechanisms underlying this observation, especially the question of whether nutritionally induced bacterial translocation is primarily related to loss of intestinal barrier function, versus an impaired immune system, remain to be fully elucidated.

METHODS

Bacterial translocation was measured in vivo, ileal mucosal membranes were harvested, and their electrophysiologic properties and barrier function were measured ex vivo in the Ussing chamber system 7 days after receiving total parenteral nutrition solution parenterally (IV-TPN) or enterally (elemental diet). Chow-fed rats served as control subjects.

RESULTS

The incidence of bacterial translocation was significantly increased both to the mesenteric lymph nodes in vivo and across the in vitro Ussing chamber-mounted ileal mucosal membranes of the elemental diet-fed and IV-TPN-fed rats. The magnitude of Escherichia coli and phenol red transmucosal passage in the Ussing chamber was significantly higher in the IV-TPN-fed rats than in the elemental diet-fed or chow-fed animals. The potential differences across the ileal membrane were similar between the three groups at all time points. However, the specific resistances of the ileal membranes of the IV-TPN and elemental diet groups were significantly less than the chow-fed animals, indicating increased membrane permeability.

CONCLUSIONS

Loss of intestinal barrier function plays a major role in nutritionally induced bacterial translocation, and the loss of mucosal barrier function to both E. coli and phenol red appeared greater in the IV-TPN than the elemental diet-fed rats.

[Respective indications of enteral or parenteral nutrition during pre- and post-operative periods]

Denutrition is often associated with poor postoperative outcome. However, a large body of evidence, from studies comparing perioperative parenteral (PN) or enteral (EN) nutrition to the absence of perioperative nutrition, suggests that perioperative nutritional support provides significant improvements in both nutritional status and postoperative clinical outcome in selected patients who are or will become malnourished. The aim of this study was to select and review all relevant articles comparing perioperative parenteral and enteral nutritional support, either in terms of clinical outcome, or risks and costs, or in pathophysiological terms. Twelve clinical reports were reviewed. All contained methodological flaws, mainly type II statistical error due to an insufficient number of patients, inaccurate primary diagnosis, absence of blinding, and lack of objective criteria of judgement. These concerns warrant caution in interpreting the results. Moderately strong (grade B) recommendations can only be drawn from these studies: PN (compared to early EN) is associated with a higher rate of sepsis in patients following abdominal trauma; EN is as efficient as PN in patients following surgery; EN is safe and cheaper than PN. PN formulae lack many important nutrients (glutamine, arginine, cysteine, peptides, fibers, n-3 polyunsaturated fatty acids, and nucleotides). Many experimental (animal) and some clinical (in non surgical patients) studies showed that PN (compared to EN) induces gut mucosal atrophy, liver dysfunction, gut bacterial translocation and immune dysfunction. The final aim of PN and EN would therefore strikingly differ. The qualitatively imperfect PN would only supply the fasting patient with quantitative amounts of calories and proteins. Due to initially limited digestive tolerance, EN provides less nutrition than PN does, but would finally lead to the same or even better outcome, due to its ability to counteract stress induced gut and immune dysfunction. Current evidence therefore suggests that early EN is superior to PN in trauma patients, and not different from but cheaper (and therefore more cost-effective) than PN in surgical patients. Further controlled, randomised, and blinded studies including sufficient sizes of groups are required, especially in the surgical setting, to address a large number of still unanswered questions.

[Effect of postoperative complications on nutritional status: therapeutic consequences]

The occurrence of a postoperative complication represents an additional stress factor for patients and leads in many cases rapidly to a malnutrition status. Thus a nutritional support is required as soon as the foreseeable duration of starvation has a longer duration than one week. Considering its lower risk of septic complications and lower cost, enteral feeding should be initiated as soon as possible. Appraisal of caloric needs with standard formulas often leads to inappropriate nutritional management. Therefore the requirements should be assessed by indirect calorimetry if available. Nutritional support is a part of the management of a postoperative septic patient. It must be initiated when initial phase of haemodynamic instability is amended. Branched chain amino acids, medium chain triglycerides and other specific nutrients have failed to demonstrate a real clinical beneficial effect. In case of acute respiratory failure, nutritional support must be cautious with regard to caloric load, as carbohydrates may increase CO2 production and lipids may worsen hypoxaemia. In case of postoperative acute renal failure, nutritional management is facilitated by continuous haemofiltration techniques allowing an unlimited nutrient intake. Solutions containing only essential amino acids are not recommended. During severe acute pancreatitis, enteral feeding is indicated when ileus does not permit the use of the intestinal tract. Jejunal access must be preferred to stomach or duodenum. Lipid emulsions can be used safely if serum triglyceride concentrations remain below 4 g.L-1 during infusion and below 2 g.L-1 between infusions.

[Consequences of surgery on nutritional status]

Trauma and surgery induce extensive physiological changes, commonly denominated the acute phase reaction (APR). This APR is activated by various kinds of stimuli, namely nociceptive stimulations, tissue injury, tissue ischaemia and reperfusion as well as by haemodynamic disturbances which occur commonly in such patients. APR is mainly characterised by the release of counter-regulatory hormones, complex metabolic changes and by the hepatic synthesis of numerous acute phase factors (C-reactive protein, haptoglobin, complement protein, etc). In addition, fever is typically present and there is a resistance to the nutritional support. The intensity of APR is variable, according to the extent of surgery, the subsequent course, occurrence of complications and to various factors related to the patient and its treatment. In patients with non complicated surgery and low or moderate severity trauma, the metabolic changes are minor and self-limited. In such a condition, there is no need for nutritional support. Conservely, in patients with complicated surgery or major trauma, there is an extensive APR, which can be very prolonged. This results in important and sustained metabolic changes, leading to extensive catabolism and progressive loss of body cell mass. The latter is amplified by the decreased body ability to adapt to starvation and by the resistance to the nutritional support that typically occur in complicated postoperative and trauma patients. Total parenteral nutrition does not prevent from metabolic changes occurring in surgical patients. By contrast, several experimental and human studies have shown that early enteral nutrition may alleviate both the endocrine and metabolic responses in such conditions. Regional anaesthesia, particularly by the epidural route, may also decrease but not abolish the extent of APR.

Clinical applications of enteral nutrition

Clinical and experimental evidence confirms that delivery of nutrients via the gastrointestinal tract reduces septic morbidity in critically injured patients. Early enteral feeding seems to maintain mucosal integrity and to support the gut as an important immunologic organ that may affect other areas of the body. There is increasing evidence to suggest that specific nutrients are especially beneficial in maintaining intestinal host-defense function in times of critical illness and injury.