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Nutrition support is an important link in the chain of therapy for intensive care unit patients. The early institution of nutrition support significantly reduces the incidence of septic complications, reduces mortality, and shortens hospital stay. Unfortunately, impaired gastrointestinal function, particularly gastric atony, restricts the use of nasogastric enteral tube feeding, and the use of this route of administration in these patients can lead to regurgitation, aspiration, and the development of pneumonia. Postpyloric enteral feeding was heralded as a means of overcoming many of these problems. Overall, the results of controlled studies do not support a role of postpyloric duodenal feeding in reducing the incidence of aspiration pneumonia. As a consequence, post-ligament of Treitz nasojejunal enteral feeding is proposed as the technique of choice in these patients. Feeding tube design must incorporate a gastric aspiration port to overcome problems of gastroesophageal acid reflux, duodenogastric bile reflux, and increased gastric acid secretion, problems that occur during "downstream" jejunal feeding. Tube placement technique will need to be refined and patients will need to receive a predigested enteral diet. In postoperative surgical patients in the intensive care unit, there is also a need for a newly designed dual-purpose nasogastric tube capable initially of providing a means of undertaking gastric aspiration and decompression and subsequently a means of initiating nasogastric enteral feeding.

Nasogastric enteral feeding is not tolerated in patients with gastric atony and in many critically-ill patients in whom gastric emptying may be delayed and in whom gastro-oesophageal regurgitation may lead to pulmonary aspiration of enteral feed and the development of pneumonia. Initial attempts to overcome these problems led to the development of post pyloric enteral feeding techniques with the infusion port of the tubes positioned in the duodenum. In many centres this technique is still the most practised post-pyloric enteral feeding technique. Nasoduodenal feeding tubes often retroperistalse into the stomach. The technique of choice, therefore, in these difficult patients is to position the infusion port of the feeding tube well distal to the ligament of trietz (post ligament of trietz nasojejunal enteral tube feeding). While nasogastric and nasoduodenal enteral feeding techniques have been shown to elicit a stimulatory exocrine pancreatic response, distal jejunal enteral feeding does not. During this mode of feeding the ileal brake is activated and pancreatic exocrine pancreatic secretion inhibited by the action of the released peptide YY and glucagon-like peptide-1 hormones, in turn the inhibition of pancreatic secretion being the result of inhibition of trypsin secretion. In the light of the findings showing the absence of a stimulatory pancreatic exocrine response to nasojejunal enteral feeding these patients should receive a predigested rather than a polymeric enteral diet.

Background: Enteral nutrition can be associated with gastrointestinal side effects and fibre supplementation has been proposed as a means to normalize bowel function., Aim: To evaluate systematically the effects of fibre supplementation of enteral feeds in healthy volunteers and patients both in the hospital and community settings., Methods: Electronic and manual bibliographic searches were conducted. Controlled studies in adults or children, comparing fibre-supplemented vs. fibre-free formulae given as the sole source of nutrition for at least 3 days, were included., Results: Fifty-one studies (including 43 randomized-controlled trials), enrolling 1762 subjects (1591 patients and 171 healthy volunteers) met the inclusion criteria. Fibre supplementation was generally well tolerated. In the hospital setting, the incidence of diarrhoea was reduced as a result of fibre administration (OR 0.68, 95% CI: 0.48-0.96; 13 randomized-controlled trials). Meta-regression showed a more pronounced effect when the baseline incidence of diarrhoea was high. In both patients and healthy subjects, fibre significantly reduced bowel frequency when baseline frequency was high and increased it when it was low, revealing a significant moderating effect of fibre., Conclusions: The review indicates that the fibre-supplemented enteral formulae have important physiological effects and clinical benefits. There is a need to use a consistent approach to undertake more studies on this issue in the community setting.

Benign pneumoperitoneum is a complication of percutaneous endoscopic gastrostomy (PEG) feeding tube placement. The rate of occurrence is reported as up to 25%. It is usually an incidental finding that arises immediately following the procedure. We report a case of pneumoperitoneum that developed a significant time after the initial procedure. The patient developed intractable vomiting and had to be fed parenterally. The pneumoperitoneum resolved and the gastrostomy tube feed was re-started.

Background and Aims: Fibres with varying fermentability may improve bowel function during enteral feeding. Two studies in healthy volunteers aimed to 1) investigate effects of Nutrison Multi Fibre (NMF) on gastrointestinal function, and 2) compare effects of NMF administered orally and nasogastrically on distal colonic motor activity., Methods: (1) Ten subjects were randomly assigned to 3x7 days self-selected diet (SSD), 2 litres Nutrison Standard (NS), or 2 l NMF. Objective and subjective indices were measured. (2) Two groups (n=6) received 2x250 ml boluses of NMF 2 hourly either nasogastrically or orally. Distal colonic motility was measured for 8 h (3 pre/5 post) first bolus., Results: Whole gut transit time was prolonged during NS (P<0.05) compared with SSD or NMF. Stool wet weight was higher during SSD (P<0.05) than during NS or NMF. Bowel frequencies were comparable. NMF was well tolerated. 2. Colonic activity index was maintained after oral administration with no associated diarrhoea. Activity index decreased after nasogastric bolus (P<0.05), but recovered to higher than fasting levels (P<0.05). 5 subjects had watery stools., Conclusions: Oral NMF is well tolerated, normalises whole gut transit time and maintains colonic motility. Recovery of colonic activity after nasogastric bolus suggests a putative protective effect of NMF over a longer period of feeding., (Copyright 2001 Harcourt Publishers Ltd.)

The number of enteral diets has increased from a handful in the 1970s to over 100 at present. These can be classified as polymeric, chemically defined, disease-specific, and specialized diets, as well as oral dietary supplements. The properties, indications, pros and cons for the use of these diets are outlined in an effort to assist clinicians in their selection.

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.

Background: Dietary fiber is known to influence bowel habit and gastrointestinal mucosal cell morphology and function. large-bowel function is particularly influenced by insoluble, poorly fermentable fiber sources, whereas mucosal function is affected by fiber sources that are soluble and highly fermentable. The aim of the present study was to compare bowel function during consumption of a self-selected diet, a fiber-free enteral diet, and three polymeric enteral diets, each supplemented with a fiber with different fermentation characteristics. The fiber sources used were oat, soy oligosaccharide, and soy polysaccharide., Methods: Seven healthy subjects consumed four diets in random order for 4 to 7 days. These were a self-selected diet, a 2-L polymeric enteral diet, and a 2-L polymeric enteral diet supplemented with 15 g of total dietary fiber per liter derived from either soy oligosaccharide fiber (75 g/L) or oat fiber (15 g/L). An additional six healthy subjects were randomly assigned to three diets (4 to 7 days): a self-selected diet, a 2-L polymeric enteral diet, or the same 2-L polymeric enteral diet supplemented with 20 g of soy polysaccharide fiber per liter (15 g of total dietary fiber per liter). Bowel function was assessed by measuring whole-gut transit time, mean daily stool wet weights, and bowel movement frequency per day. Fermentation characteristics of the different fiber sources were determined quantitatively and qualitatively by measuring short-chain fatty acids produced during in vitro stool culture., Results: Total short-chain fatty acid and butyric acid production with soy oligosaccharide fiber were significantly higher compared with values observed for soy polysaccharide fiber (p < .003), oat fiber (p < .005), and self-selected (control) diet (p < .003). Compared with the fiber-free diet, consumption of the soy polysaccharide, oat, and soy oligosaccharide-fiber-supplemented enteral diets did not significantly (p > .05) alter whole-gut transit time or stool wet weight. However, bowel frequency was significantly improved by consumption of the soy polysaccharide-fiber-supplemented diet but not the oat fiber or soy oligosaccharide-fiber-supplemented diets., Conclusion: Compared with a fiber-free polymeric enteral diet, the daily consumption of an enteral diet supplemented with 30 g of total dietary fiber per day derived from a poorly fermentable oat fiber, a highly fermentable soy oligosaccharide fiber, or a moderately fermentable soy polysaccharide fiber has little impact, if any, on bowel function.

Diarrhoea complicating enteral feeding is a common clinical problem affecting up to 25% of patients. Its pathogenesis remains unknown. A new technique of human in vivo segmental colonic perfusion was used to investigate colonic water and electrolyte movement in response to enteral feeding. Four groups of studies were performed in which low and high load polymeric enteral diet infusions were undertaken, either intragastrically or intraduodenally (n = 6 each group). Net absorption of sodium, chloride, and water occurred during fasting throughout the colon in all groups. There was a significant net secretion of sodium, chloride, and water in the ascending colon during low load (sodium: -42 mmol/h; 95% confidence limits -52 to -19, Chloride: -18 mmol/h; -50 to +16, water: -174 ml/h; -348 to -30) and high load (sodium: -24 mmol/h; -60 to +8, chloride: -18 mmol/h; -31 to +16, water: -120 ml/h; -246 to +6) gastric feeding, and during high load duodenal feeding (sodium: -12 mmol/h; -22 to -6, chloride; -6 mmol/h; -16 to +3, water: -72 ml/h; -144 to -6). Net secretion persisted in the distal colon only during high load gastric feeding. In the other three groups there was a net absorption in the distal colon. This study identified a significant colonic secretory response to enteral feeding, which is related to the site and load of the diet infusion. This response may play an important part in the pathogenesis of enteral feeding related diarrhoea.

Diarrhoea complicates enteral feeding in up to 25% of patients. In-vivo perfusion studies in healthy subjects have shown secretion of salt and water in the ascending colon in response to enteral feeding. This study investigated the effect of short-chain fatty acids (SCFA) on this secretory response. Six healthy volunteers underwent segmental in-vivo colonic perfusion. First, baseline fasting colonic water and electrolyte movement was established, then a standard polymeric enteral diet was infused into the stomach while the colon was perfused with either a control electrolyte solution or a test solution containing SCFA. The electrolyte concentrations and osmolality of the two perfusates were identical. In the fasting state water was absorbed throughout the colon. During the control infusion there was significant (p < 0.05) secretion of water in the ascending colon (median rate 1.0 mL per min [95% CI 2.8 mL per min secretion to 0.8 mL per min absorption]). During the SCFA infusion the secretion was significantly reversed (p < 0.05) and there was net absorption (1.6 [0.8-3.7] mL per min). In the distal colon water absorption was significantly greater during the control infusion than during fasting (3.7 [2.5-4.6] vs 1.3 [0.3-2.2] mL per min); during the test infusion this absorption persisted (2.8 [1.3-3.6] mL per min). Movement of sodium, chloride, and potassium ions was similar to that of water in all stages of the study. Bicarbonate movement did not significantly change at any stage. Infusion of SCFA directly into the caecum reverses the fluid secretion seen in the ascending colon during enteral feeding. This finding could have implications for the management of diarrhoea related to enteral feeding.

This prospective double blind randomised seven day crossover controlled clinical trial was carried out to determine whether enterally fed patients with moderately impaired gastrointestinal function require a predigested nitrogen (N) source compared with whole protein. Twelve malnourished patients with varying gastrointestinal abnormalities, who required enteral feeding, received 2.25 l of one of two isocaloric isonitrogenous enteral diets (1 kcal/ml, 4.8 g nitrogen/l) containing either predominantly medium chain peptides (tetra or higher peptides) or whole protein as the nitrogen source. Nitrogen absorption and balance were calculated from dietary intake and analysis of 24 hour total urinary and faecal nitrogen for the last five days of each study period. There was no significant difference in either stool weight (110 (SEM) (49) v 111 (32) g/d), nitrogen absorption (91 (2) v 89 (2)%) or nitrogen balance (+1.0 (1.3) v +0.6 (1.4) g nitrogen/d) between the peptide and whole protein nitrogen sources when all patients are considered. There was, however, evidence to suggest a nutritional advantage from administering an enteral diet whose nitrogen source comprises oligopeptides, rather than whole protein, to a subgroup of patients with small bowel disease.

A prospective clinical study in three phases was performed to determine whether it was possible that enteral diet containers could become contaminated as a result of endogenous organisms ascending retrogradely from the enteral feeding tube via the giving set, and if this did occur whether the incidence could be altered by modifying enteral delivery systems. Each phase observed patients on enteral feeding over a 48-hour study period (phase I, n = 18; phase II, n = 17; phase III, n = 18). Each patient was prescribed an enteral diet of 2 L/24 h administered by continuous pump infusion from a closed 1-L sterile diet container. Four containers were used for each patient, and one giving set was used in the 48-hour period. Diet samples were taken at 12-hour intervals: two from the giving set before and after flushing with residual diet, and one from the diet container. Phases differed only in the design of the giving set: phase I had no drip chamber, phase II had a drip chamber, phase III had a drip chamber and an anti-reflux ball valve at the distal end. Both phase I and III had greater numbers of giving set samples colonized at 24, 36, and 48 hours. In phase I, 3 of 14 sterile diet containers were colonized with greater than 10(4) colony-forming organisms/mL of diet at 48 hours. Only phase II had no organisms contaminating the containers at 48 hours. We conclude that the retrograde spread of organisms from patient to sterile diet container does occur in clinical practice, and that a drip chamber in the giving set may prevent the problem.(ABSTRACT TRUNCATED AT 250 WORDS)

It is clear that the nutritional state of patients with inflammatory bowel disease is often impaired and can be improved by the provision of nutritional support. Improvement in nutritional status can be achieved as effectively with enteral as with parenteral nutrition. Nutritional support appears to have no primary therapeutic effect in patients with ulcerative colitis. With regard to nutritional support in Crohn's disease, parenteral nutrition should be restricted to use as supportive rather than primary therapy. Available information now seems to suggest that most of the benefits of parenteral nutrition in Crohn's disease are related to an improvement in nutritional state rather than as primary therapy, and its use should be restricted to the treatment of specific complications of Crohn's disease, such as intestinal obstruction related to stricture formation or short bowel syndrome following repeated resection. Although some doubt exists over the efficacy of oligopeptide-containing elemental and polymeric enteral diets, the present evidence indicates that chemically defined free amino acid-containing elemental diets have primary therapeutic efficacy in the management of acute exacerbations of Crohn's disease. As such, these diets are worthy of therapeutic trial in patients with severe Crohn's disease involving the distal colon and rectum, particularly in those patients who are malnourished and who prove to be resistant to treatment with a combination of topical corticosteroids and 5-aminosalicylic acid-containing compounds. Clinicians should be aware, though, that the beneficial effects are likely to be restricted to the short term, with high relapse rates by 1 year, this being particularly so in patients with distal Crohn's proctocolitis (Teahon et al, 1988). Volatile fatty acid enemas clearly have potential in the management of patients with severe steroid-resistant proctitis. Finally, one of the most important observations made in recent years is the one concerning the large losses of nitrogen that will occur in patients with inflammatory bowel disease treated with corticosteroids in the absence of adequate protein intake (O'Keefe et al, 1989). Hopefully the days of treating patients with severe inflammatory bowel disease with high dose corticosteroids and a peripheral dextrose or dextrose-saline drip have passed into history.

The increasing sophistication of enteral and total parenteral nutritional support techniques has resulted in improvements in the clinical practice of such support in recent years. This survey was designed to establish current clinical practice in the management of nutritionally-compromised hospital patients in 206 districts in the United Kingdom. However, despite recent developments in these techniques, the response revealed a wide variation in the practice of clinical nutritional support. The results also indicate that in each district there should be a group of people, with an interest in clinical nutrition, to monitor and advise on nutritional support. It is suggested that, a national multidisciplinary group should be formed, similar to the American and European Societies of Parenteral and Enteral Nutrition. The group would promote the appropriate use of, and research into, nutritional support specifically for the nutritionally compromised patient in the United Kingdom.

Results of recent controlled studies show that because of difficulties in administering adequate quantities of enteral diet, positive nitrogen balance is not consistently achieved during enteral feeding. In order to determine whether nitrogen balance can be improved in routine clinical practice by prescribing enteral diets containing higher concentrations of nutrients, 118 patients with normal gastrointestinal function needing enteral nutrition were randomised to receive daily 21 of one of three polymeric diets: Standard diet (1.0 kcal/ml; 6.3 gN/l), Energy Dense diet (1.5 kcal/ml; 7.8 gN/l), and Energy-Nitrogen Dense diet (1.5 kcal/ml; 9.4 gN/l. The three diets, administered by continuous nasogastric infusion, were equally well tolerated. Results were analysed only for patients fed five or more days and who received at least 60% of prescribed enteral diet (n = 42). Positive nitrogen balance was achieved only in the patients receiving the Energy-Nitrogen Dense diet (n = 16; + 1.6 (SE) 0.6 gN/d, compared with the Standard diet (n = 12; -3.8 (1.1) gN/d; p less than 0.001), and the Energy Dense diet (m = 14; -1.9 (0.8) gN/d; p less than 0.005). As the findings of this prospective controlled trial show that positive nitrogen balance was not consistently achieved by administering 21 enteral diet containing up to 15.6 gN, consideration could, therefore, be given to routinely using enteral diets containing up to 9.4 gN/l.

One hundred and eighteen patients with normal gastrointestinal function were randomly allocated to one of three feeding regimens in a double blind study to determine the relation between the tonicity of the diet and gastrointestinal side effects related to the diet and to evaluate the efficacy of "starter" regimens in reducing gastrointestinal side effects during enteral nutrition. Patients received a hypertonic diet with an osmolality of 430 mmol (mosmol)/kg (group 1), the same diet but with the osmolality increasing from 145 to 430 mmol/kg over the first four days (group 2), or an isotonic diet (300 mmol/kg) (group 3). All diets were prepared aseptically and administered by 24 hour nasogastric infusion. The mean daily nitrogen intake in group 1 was significantly greater (p less than 0.05) than that in both groups 2 and 3, and the mean overall daily nitrogen balance was significantly better (p less than 0.05) in group 1 than groups 2 and 3. The incidence of side effects related to the diet was similar in all three groups, but diarrhoea was significantly (p less than 0.001) associated with concurrent treatment with antibiotics. These findings show that undiluted hypertonic diet results in significantly better nitrogen intake and balance, that starter regimens reduce nutrient intake but not symptoms, and that diarrhoea is significantly related to treatment with antibiotics and not to administration of an undiluted hypertonic polymeric diet.

Enteral nutrition is only part of the wider field of clinical nutrition in which great advances in both theory and practice have been made over the last decade. We have attempted to summarize what we consider to be the advances that have most relevance to the clinical practice of enteral nutrition. This chapter reviews our present understanding of the processes of digestion and absorption of protein, carbohydrate and fats, and examines how this theoretical understanding can be applied to patients in the clinical situation. A broad classification of the different enteral diets is undertaken, and the reasons for the development of particular diets are discussed. The clinical value of these diets is assessed. The wide variety of indications for enteral (as opposed to parenteral) nutrition are discussed and the specific benefits of enteral nutrition for the patient are highlighted. Techniques of administration of enteral nutrition are reviewed in detail, and the methods by which enteral nutrition should be monitored are outlined. Finally, complications of enteral nutrition are summarized and advice given on how to prevent or treat them.

Certain groups of patients requiring enteral nutritional support are at increased risk of regurgitation and pulmonary aspiration of feed. Positioning of enteral feeding tubes distal to the pylorus has been advocated as a method of reducing such complications. Various techniques have been suggested to achieve postpyloric siting. Reports have indicated that lengthening the tube or altering the distal end tip configuration, by varying the tip profile or by the addition of a weight, may facilitate spontaneous transpyloric passage of the tube. This prospective controlled clinical study using three new polyurethane tubes demonstrates that the frequency of spontaneous transpyloric passage of the tube is not affected by tip profile or by the addition of a weight. Indeed, with all three tube designs only about one-third had passed spontaneously through the pylorus at 24 hr. Once through the pylorus the unweighted tube stayed in position significantly longer than the weighted tubes (p less than 0.005). We suggest that in those patients requiring post-pyloric feeding, endoscopic or fluoroscopic techniques should be used to position the tubes at the time of insertion, and that an unweighted tube should be used to prolong tube usage.

Although there has been agreement that enteral nutrition remains an excellent means of providing nutritional support to malnourished patients with normal or near normal gastrointestinal function, it is clear that areas of controversy do exist, and attention needs to be directed towards these in the future.

In a prospective controlled clinical trial, 70 patients with normal gastrointestinal function were randomised to receive either an elemental diet based on Vivonex HN or an isonitrogenous isocalorie polymeric diet based on Clinifeed 400, administered by continuous 24 hour nasogastric infusion. The two groups of patients were well matched for age, sex, diagnosis, prior starvation, duration of feeding, initial nutritional status, and metabolic status. Nitrogen losses were significantly less on the polymeric feed, despite similar intakes. Serum transferrin rose significantly (1.85 +/- 0.2 to 2.30 +/- 0.2 g/l, p less than 0.05) only in the Clinifeed group, but nutritional parameters were otherwise maintained in both groups. The incidence of diarrhoea (Vivonex, 23.5%; Clinifeed, 30.6%) was not significantly different and was attributable to antibiotics in most cases. Hypokalaemia, which occurred in nearly half the patients, was equally distributed in the two groups, but hypophosphataemia occurred more often in the Vivonex group (p less than 0.05). Liver enzyme disturbances were similar in both groups. The present findings, therefore, provide no evidence that chemically defined 'elemental' diets containing free amino acids as their nitrogen source are in any way superior to polymeric diets containing whole protein and fat when administered to patients with normal gastrointestinal function.

Jejunostomy losses of Na+ and water during enteral nutrition after massive intestinal resection may be severe. We have attempted to analyse this practical problem by using an in vivo perfusion technique in healthy volunteers to study Na+, water and nutrient absorption from a short (25 cm) segment of jejunum during perfusion of an isotonic solution of the elemental diet Vivonex. Further solutions made from the amino acid and carbohydrate components of Vivonex were also perfused in part I of the study in order to determine the causes of the marked Na+ and water secretion seen during Vivonex perfusion. Low initial Na+ concentration was found to be the major determinant of net Na+ secretion, initial Na+ concentration correlating significantly with Na+ absorption (r = 0.95, n = 7 p less than 0.001). Water absorption correlated with net absorption of NaCl (r = 0.82, n = 7 p less than 0.01). There was, however, a better correlation with total absorption of NaCl plus amino acids (r = 0.99, n = 7, p less than 0.01). In part II of the study separate isotonic solutions of NaCl, glucose, and the polymeric diet, Ensure were also studied. Net sodium secretion occurred during glucose and Ensure perfusion, as predicted from their low Na+ concentration. Owing to rapid sucrose absorption from Ensure there was substantial luminal disappearance of osmotically active particles and hence marked water absorption, which was accurately predicted using the regression equation for water absorption derived in part I, substituting sucrose absorption for amino acid absorption. We conclude that the marked Na+ and water secretion observed during Vivonex perfusion is not a unique property of this amino acid based diet but is due to its low Na+ content.

Ten patients with histologically proven cirrhosis, admitted in grade I to II acute hepatic coma, received in addition to a standard dietary protein free "anticoma" regime, a continuous nasogastric infusion of a branched-chain amino acid enriched chemically defined enteral diet (Hepaticaid) containing an equivalent of 70 g protein/day for a mean of 7.3 days (range 3-23). No complications of therapy were observed and, specifically, the use of fine bore tubes did not provoke variceal hemorrhage. Overall positive nitrogen balance (4.3 +/- 1.7 g N/day) was observed in patients fed 7 or more days. Improvement to coma grade 0 was seen in all patients save one, who died from hepatorenal failure. While serum ammonia levels remained elevated during the study period, there was a significant increase in the branched-chain/aromatic ratio (p less than 0.01) as plasma branched-chain amino acids rose (p less than 0.05) and tyrosine levels fell (p less than 0.05).

The recent launch of a number of fibre enriched polymeric diet in the United States and Europe has stimulated considerable interest in the topic of fibre and enteral nutrition, and several commercial concerns appear to be under considerable pressures from their consumers to produce similar products. As a means of identifying areas of potential application of fibre to enteral nutrition some of the recent knowledge gained about the physical properties of dietary fibre and the processes involved in the intestinal assimilation of fibre has been reviewed. Two areas of interest are identifiable. The first relates to the bulking properties of fibre and the application of this to the regulation of bowel function in enterally fed patients. It is clear from the clinical studies that have been reviewed that there remains a paucity of controlled data, and a great deal more research is needed before widespread use of fibre supplemented diets can be supported. Perhaps of greater interest academically is the potentially beneficial effects that appear to be exerted by the VFA's, liberated as a consequence of colonic bacterial fermentation of fibre, on morphology and function of ileal and colonic mucosa. Although there are a number of potential applications of fibre supplemented enteral diets in this area, more research is required before any firm recommendations can be made about recommending their use. The one exception concerns patients with the nutritionally inadequate short bowel syndrome. There does seem to be sufficient experimental evidence to suggest that clinical studies should be commenced using a pectin supplemented predigested 'elemental' diet in these patients. Overall therefore, one is forced to conclude that the increasing interest and use of fibre supplemented enteral diets is being driven more by market than scientific forces. Nevertheless, the promotion of these diets has already provided a powerful stimulus to the scientific community, and it remains entirely possible that many of the potential applications of these diets will be realised in the near future.

Of 80 patients fed enterally over nine months, 10 had serious gastrointestinal complications from gravity-controlled continuous enteral feeding. Use of an infusion pump controlled diarrhoea in patients with gastrointestinal disorders, but was less successful in patients with poor gastric emptying or impaired swallowing reflexes. Thus a pump is not indicated for routine use but, in carefully selected patients, it can obviate the necessity for parenteral nutrition.

We report here our clinical experiences of "fine bore" nasogastric feeding tubes. Data have been collated over a 7-year period (1978-1985). A total of 403 patients were intubated on 809 occasions. In the first retrospective study, the clinical use of 491 unweighted tubes was compared with that of fifty 3.5-g weighted tubes. No advantage was found in the use of the weighted tubes. In the second prospective controlled clinical trial, these results were confirmed. Forty-six patients were intubated on 76 occasions with an 85-cm open-ended, unweighted nasogastric feeding tube (Prima, Portex UK), and 57 patients were intubated on 79 occasions with a 91-cm 3.0-g weighted tube (Entriflex, Biosearch, Raritan, NJ). Mean duration of placement was similar in each case, and 62% of both types of tubes were inadvertently removed. Without exception, all the tubes remained in the stomach throughout. Disappointed with the similar and overall performance of both types of tubes, we initiated a design program which resulted in the development of two new nasogastric tubes, one weighted and one unweighted. The tubes were manufactured with polyurethane, rather than polyvinylchloride (PVC), which permitted an increase in diameter of the internal lumen which, in turn, was coated with water-activated lubricant to ease removal of the introducer wire. A specially modeled outflow port was incorporated into the tips of both tubes. The performance of the two new polyurethane nasogastric feeding tubes was assessed under controlled trial conditions; as a reference, a widely used PVC unweighted open-ended tube was used.(ABSTRACT TRUNCATED AT 250 WORDS)

Following a recent study in our Unit which showed that significantly more of prescribed enteral diet was administered from 2-liter bags than 0.51 bottles, a controlled clinical trial was undertaken to investigate further the effectiveness of the 2-liter prepackaged enteral delivery system. Forty patients with normal gastrointestinal function requiring enteral nutrition were randomized to receive nasogastrically 2-liter/day of polymeric diet (2000 kcal, 12 g N) either from a presterilized 2-liter PVC bag (Express EFI Ltd, UK) or from two 1-liter rigid plastic containers filled with cans of Clinifeed 400 (Roussel Laboratories Ltd, UK). The actual volumes of feed infused were monitored in patients fed for 5 days or more. Both nursing and dietetic staff preferred the 2-liter bags which were more convenient to prepare and use. Significantly larger quantities of prescribed diet were delivered from the 2-liter bags than from the 1-liter containers (p less than 0.001). It was concluded that the 2-liter bag system was potentially more convenient and nutritionally efficacious than 1-liter containers. Although the incidence of microbial contamination associated with the 2-liter bags was low, measures to maintain the sterility of this system may need to be more stringent.