Formulation of enteral diets for use in jejunal 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.     

Clinical indications for weighted enteral feeding tubes

Simple unweighted fine bore feeding tubes have been used by our Nutritional Support Team for routine nasogastric feeding with success in large numbers of patients. Three clinical situations where mercury or tungsten weighted tubes offer advantages over fine bore tubes have been defined. Significant advantages in patients with concurrent endotracheal intubation, gastric atony and severe oesophageal stricturing are described.     

Bacterial colonization of enteral feeding tubes

An in-vitro model system was used to determine the number of bacteria infused into a 'patient' when three types of polyurethane enteral feeding-tubes that had been experimentally contaminated with feed containing K . aerogenes on day I, were then perfused with sterile feed for periods of 8 h on three consecutive days (days 2–4). The tubes were syringed with 20 ml sterile water at regular intervals. Viable counts were made on syringe washings, feed collected from the ends of the tubes and feed from the nutrient containers.
On day 1, the total number of K . aerogenes in feed samples collected from the nutrient containers and the ends of the tubes rose from 10² to 103–10⁴ cfu ml^-1 over 8 h. On days 2–4 no organisms were detected in the feed samples from the nutrient containers whereas viable counts on feed samples collected from the tubes and syringe washings rose from 10⁴ to 10⁷ and from 10¹ to 10⁷ cfu ml^-1 respectively.
It can be concluded that a single incidence of feed contamination could lead to a patient receiving contaminated feed from an enteral feeding-tube colonized with bacteria which will not be detected by normal monitoring of the remainder of the system.     

Endoscopic placement of enteral feeding tubes

The techniques for placement of feeding tubes using fiberscopes are described and an evaluation of the results obtained in the last 12 months is made. The techniques are discussed and compared with other methods of enteral feeding known at present. It is concluded that placement of feeding tubes by endoscopy can be achieved easily, that it is possible to choose the site of enteric liberation of nutrients under conditions which previously represented contraindications, and that this procedure is free of complications even during long periods of time.     

内镜下放置鼻空肠营养管的方法和营养效果分析

目的:探讨分析内镜下放置空肠营养管的方法和营养支持效果。方法:选择106例需放置空肠营养管的病人随机分为观察组54例和对照组52例。此外,选择同期行鼻胃管肠内营养病人43例作为鼻胃管组。对照组采用传统内镜下经鼻空肠营养管置管术;观察组采用改良后内镜下经鼻空肠营养管置管术;鼻胃管组采取常规鼻胃管肠内营养。比较三组病人手术时间、一次性置管成功率、置管后并发症发生率以及病人置管后营养指标变化情况。结果:观察组和鼻胃管组病人手术时间显著短于对照组(P0.05),一次性置管成功率显著高于对照组(P0.05)。三组病人置管后并发症发生率无显著性差异(P0.05)。三组病人置管后血红蛋白、血清清蛋白以及前清蛋白水平均较治疗前显著改善(P0.05)。观察组和对照组病人置管前后营养指标比较均无显著性差异(P0.05),而鼻胃管组病人置管后血红蛋白、血清清蛋白和前清蛋白水平显著低于观察组和对照组(P0.05)。结论:改良内镜下鼻空肠管置管术能有效缩短置管手术时间,提高一次性置管成功率,降低病人置管手术的痛苦。置管后病人营养支持效果显著。     

The importance of early postoperative enteral feeding

There are still many uncertainties about giving early postoperative enteral nutrition to patients undergoingmajor abdominal surgery. In this article we describe some possible benefits of early feeding through a brief review of the literature and results from a placebo-controlled study of early postoperative enteral feeding in patients undergoing predominantly lower gastrointestinal surgery. This study showed a reduction of postoperative infections. Other studies have not been able to show the same benefit. Possible reasons for these discrepant findings are discussed. In certain situations, early postoperative nutrition may be cost-effective because of fewer re-operations, fewer days in the intensive care unit, and fewer infections. Previously unpublished data suggest that enteral nutrition has an influence upon the postoperative shift of fluid which may be an important mechanism explaining its effects. One of the greatest barriers to the introduction of early postoperative nutrition into a surgical department seems to be the disagreement among surgeons about this procedure and its relevance. Results from a Danish department show that it is possible to administer about 90% of the required daily energy intake during the first 2 postoperative days after acute and elective abdominal surgery through the use of a nasoduodenal tube.     

The history of enteral nutrition therapy: from raw eggs and nasal tubes to purified amino acids and early postoperative jejunal delivery

Although enteral feeding therapy has existed since ancient Egypt, most of the major advances in enteral feeding techniques and formulas took place during the 20th century, including postpyloric tube placement in 1910; continuous and controlled delivery of liquid nutrition in 1916; feeding during surgery and modification of macronutrients in 1918; feeding via a pump in 1930; recognition of the importance of nutrition therapy during injury recovery and the addition of micronutrients and early postoperative feeding in 1940; the introduction of commercial products during the 1950s with chemically defined formulas following a decade later; and the development of modern formulas during the 1970s. The purpose of this review is to provide a historical account of enteral nutrition, including modes and routes of delivery, types of diet, and refinements in delivery techniques and formulas and to offer the history of the therapy as a resource for developing and improving enteral feeding techniques and therapies and implementing optimal patient care strategies.     

Microbial contamination of enteral feeding tubes occurring during nutritional treatment.

Enteral nutrition is an effective treatment for catabolic patients with normal intestinal absorption. However, tube-fed patients are at risk from superinfection. Our study is the first to evaluate in vivo the microbial contamination of solutions staying in the nasogastric tube of cancer patients receiving nutritional preparations. After daily feeding, the tube was rinsed with nonsterile tap water. Tap water staying overnight in the tube was considered as tube-rinsing solution. Microbial burden of nutritional preparations was determined on the fifth day of enteral nutrition, from opening the first container and throughout feeding. The next day, a sample of the tube-rinsing solution was cultured. All bacterial species were identified and antibiotic susceptibility pattern was assessed. Thirty-one cancer patients were included, 12 on the hospital's preparations and 19 on commercial feeding. Seven of the hospital--and none of the commercial--preparations were contaminated. Among the 48 samples collected during feeding, 16 were contaminated, including 10 hospital and 6 commercial preparations. All the 31 tube-rinsing solutions were contaminated and 102 strains cultured. Their median concentration was 10(6) colony-forming units/mL (range 10-10(10)). The strains were 48 Enterobacteriaceae, 20 group D streptococci, 9 Candida albicans, 9 Pseudomonas aeruginosa, and 16 others. Multiple antibiotic resistance was present in 12 of the 102 strains. Lower resistance was present in 33. The predominant microorganism of the tube-rinsing solution caused a bacterial colonization for three febrile patients. In conclusion, the feeding tube is an important reservoir for multiple antibiotic-resistant bacteria.     

Scanning electron microscopy of the internal wall topography of enteral feeding tubes

A range of commercially available naso-gastric and naso-enteric tubes was examined by scanning electron microscopy (S.E.M.). Surface irregularities in which micro-organisms could become trapped were observed on the internal walls of all the samples. Fine bore tubes which had been perfused for 8 h with a milk based feed experimentally contaminated with Staphylococcus aureus showed patches of residual feed and S. aureus cells on their interior surfaces. The potential hazards of entrapment and/or attachment of micro-organisms to the interior walls of these tubes are discussed.     

Influence of unclogging agents on the surface state of enteral feeding tubes

Background: Despite standardized prevention procedures, recalcitrant clogging of enteral feeding tubes is observed, which requires recourse to varied unclogging agents. Some of these agents have proved effective in routine use, but their impact on the surface state of the tube materials has never been studied. In this work, the authors tested the impact of different unclogging agents on the materials used for these tubes (polyurethane and silicone). Methods: Enteral feeding tubes were placed in contact with different agents in vitro, and the surface state of the material was analyzed using 2 different methods: infrared spectroscopy and scanning electron microscopy. To assess the surface state of the silicone and polyurethane tubes, negative controls (undamaged tubes) and positive controls (deliberately damaged tubes) were used for each type. Results: The infrared spectroscopy method did not reveal any damage to the surface of either the silicone or the polyurethane tubes with either treatment. The test results by scanning electron microscopy showed that orange juice, pineapple juice, and cola had no detrimental action on the tube biomaterials under current conditions of clinical practice. Conclusions: Although some studies have advocated using polyurethane tubes to administer medication, silicone appears to be less vulnerable to damage by the agents tested.     

保留空肠营养管在胃癌术后化疗期间的应用价值

目的 探讨保留空肠营养管在胃癌术后化疗期间的应用价值.方法 总结42例胃癌根治术后行辅助化疗患者的临床资料,术中常规放置空肠营养管,将所有病例按术后病理分期及肿瘤部位随机分为A、B两组,每组各21例,A组保留空肠营养管并在化疗期间经空肠营养管行肠内营养,B组不保留空肠营养管在化疗期间按日常进食,分别比较两组化疗前后营养及免疫指标,比较两组患者呕吐的发生率.观察长期保留空肠营养管的并发症.结果 化疗后A组营养及免疫指标较B组明显提高,两组比较差异有统计学意义(P＜0.05).A组呕吐发生率为18.3%,显著低于B组发生率(35.7%)(X2=9.75,P＜0.01).长期保留空肠营养管未发生严重并发症.结论 保留空肠营养管在胃癌术后化疗期间行肠内营养能显著改善患者的营养及免疫状况,且安全可靠,值得推广.     

Comparison of the metabolic effects of continuous postoperative enteral feeding and feeding at night only

The effects of two different feeding patterns on oxygen consumption, nitrogen balance, blood biochemistry, and urinary catecholamine excretion were investigated over 5 d in patients after major head and neck surgery. Both groups of nine patients each were fed a regimen that provided 4.7 MJ on day 1 and 10 MJ on days 2-5 via a nasogastric tube by continuous infusion with an enteral feeding pump. One group was fed continuously for 24 h, the other was fed only at night, ie, from 1700 to 0900 the next morning. Oxygen consumption was significantly higher (P less than 0.01), nitrogen balance better (P less than 0.05), and urinary catecholamine excretion higher (P less than 0.05) in the 24-h-fed patients than in the night-fed patients. Postoperatively, feeding at night only is more energy efficient than is feeding continuously for 24 h, but is associated with poorer nitrogen balance. These differences may be mediated by sympathoadrenal mechanisms.     

胃肠外科老人术后早期空肠输注肠内营养护理

目的: 对应用综合护理干预模式对接受胃肠外科手术治疗的老年患者在术后早期空肠输注肠内营养支持过程中实施护理的临床效果进行研究.方法:选择接受胃肠外科手术治疗的老年患者86例,随机分为对照组和观察组,每组43例,在术后均实施早期空肠输注肠内营养支持.采用综合护理干预模式对观察组患者在营养支持期间实施护理;采用常规护理模式对对照组患者在营养支持期间实施护理.结果:观察组患者对术后营养支持期间的护理服务满意度明显高于对照组;术后营养支持计划实施时间和住院时间明显短于对照组.结论:应用综合护理干预模式对接受胃肠外科手术治疗的老年患者在术后早期空肠输注肠内营养支持过程中实施护理的临床效果非常明显.     

Subjective distress during continuous enteral alimentation: superiority of silicone rubber to polyurethane

A small-bore feeding tube of silicone rubber was developed in order to improve the acceptance of enteral feeding. The insertion procedure was facilitated by providing a double guidewire which allows continuous adjustment of tip rigidity. The usefulness of this tube was tested in a short-term and a long-term volunteer study as well as in a prospective follow-up of patients receiving enteral nutrition. The volunteer study showed that the newly developed tube significantly reduced subjective distress (rank value 14) when compared to a conventional tube made of polyurethane (rank value 20). In the patient study, 131 silicone rubber tubes were used in 85 patients who received enteral nutrition for a total period of 2080 days and complained about foreign-body feeling and rhinorrhea in only 3.7% and 0.5% of the days, respectively. The rate of inadvertent removals was relatively low (32%), mainly due to restricted mental status of the patients.     

肿瘤患者术后用特殊配方与标准配方肠内营养二周的效果比较

目的 观察五官科肿瘤病人作喉切术使用肿瘤特异性免疫营养配方肠内营养对患营养、免疫的调理作用。方法 本研究是一个随机、前瞻、控制、双盲的临床研究。40例手术的五官科肿瘤病人随机分为两组：（1）免疫营养组（Supportan n=20)，（2）标准营养组（n=20)，两组使用等热量的肠内营养管饲，均为连续性鼻胃途径泵辅助喂养。手术当天、术后第1天及喂饲结束当天进行体格检查、询问营养史、人体测量、抽取静脉血作实验室分析检测包括TNFα、IgA及血糖等指标。统计学方法：方差分析，对数转化或mann-Whitney U-检验。结果 手术导致大部分的指标参数发生显变化，且两组的变化接近。本研究中Suportan显示了良好的胃肠道耐受性，并显示出营养和免疫的调理作用。     

The effect of early postoperative jejunal feeding on the exocrine function of the pancreas

Subsequent to pancreatoduodenectomia with pylorus retention on 12 patients suffering from chronic pancreatitis we analysed the effect of artificial nutrition on pancreas-secretion by examining the pancreatic juice extracted directly from the Wirsung duct. We used post-operative nutrition administered by fine-needle catheter jejunostomy in 7 patients and 5 patients received postoperative support by total parenteral nutrition as a control-group. We analysed the pancreatic juice collected in four hour fractions for volume, direct protein, amylase, chymotrypsin, bicarbonate. It has been found that on the first two days after the operation we can see a slow increase in the measured values and on the third postoperative day after an abrupt rise the pancreas secretion became steady. Between the two methods of artificial nutrition applied it was impossible to prove an observable difference concerning their effect on the pancreas. According to our observations the two methods are equivalent in the postoperative therapy of patients operated on because of chronic pancreatitis.