Taste threshold and acceptability of commercial diets in cancer patients

An important factor in the etiology of anorexia in cancer may be a change in the sensation of taste. Taste thresholds for the four basic tastes were measured in 50 cancer patients and 50 control subjects. Cancer patients had a higher mean threshold for recognition of sweet (126 mmol/1 sucrose), and a lower mean threshold for bitter (620 mmol/1 urea), compared to the controls (86 mmol/1 sucrose, p = 0.027, and 728 mmol/1 urea, p = 0.002). There was no significant difference in the mean threshold for sour or salt. Eight commercial diets (Build-up, Nutrauxil, Ensure, Clinifeed, Triosorbon, Complan, Isocal, Vivonex) were given to each of the cancer patients and control subjects in order to investigate any possible difference in preference. Scores were often improved by the addition of tasting agents such as Nesquick. Scores for each feed were similar for control and cancer patients apart from Nutrauxil, Ensure and Isocal, which appeared to be preferred by cancer patients. Too much emphasis is often placed upon the contents of formulated diets and too little upon taste and patient acceptability.     

Assessment of the suitability of food colouring materials as indicators of bacterial contamination of enteral feeds

The suitability of using food colouring materials in enteral feeds as indicators of bacterial contamination was examined. Experiments using Triosorbon, Clinifeed ISO or Vivonex Standard plus amaranth, carmoisine, ponceau 4R, sunset yellow FCF, tartrazine or erythrosine demonstrated that although the change in appearance of coloured feed could be linked with the presence of high numbers of bacteria in the feed, the converse was not always true.     

Long-chain triglycerides reduce the efficacy of enteral feeds in patients with active Crohn's disease

Elemental diets are effective treatments for active Crohn's disease. To determine which dietary constituents are of therapeutic importance, the effectiveness of four separate feeds was related to their compositions, and the findings substantiated by meta-analysis of previous dietary studies. 76 patients with active Crohn's disease were recruited. 17 were randomised to an amino acid-based elemental diet (E028), 22 to E028 with added long-chain triglyceride (E028 LCT), 18 to a semi-elemental, peptide based diet (Pepdite 2+) and 19 received E028 with added medium-chain triglyceride (E028 MCT). Disease activity fell in all groups and remission rate was negatively correlated with the amount of energy derived from LCT (r = -0.97, p = 0.016). Inflammatory indices fell in the groups (E028 + E028 MCT) containing least LCT. No other dietary constituents correlated with remission rate. A meta-analysis of published studies confirmed a negative correlation between remission rate and LCT (r = -0.63, p = 0.006) but not other constituents. The association between dietary LCT and remission rate may have pathogenic significance and allow the development of more effective enteral feeds.     

In vitro flow rates of enteral solutions through nasoenteric tubes

Enteral solutions must flow freely through nasoenteric tubes selected for gravity drip administration particularly in outpatients receiving nutritional support. This study determined in vitro flow rates of solutions with intact protein and hydrolyzed protein sources with various caloric densities. Each solution was infused through silicone rubber and polyurethane tubes of various lengths and bore sizes. Flow rates were measured five times at 25 degrees C using formula bags and drip sets hung at a uniform height and tubes uniformly positioned in a collecting vessel. Data are presented for tubes and formulas tested. Recommendations for selection of tubes for gravity drip administration are made based on flow rate data, patient comfort, administration convenience, and patient tolerance to osmolality.     

Hyperkalemia in patients on enteral feeding

The amount of potassium (K) in proprietary enteral feeds varies considerably from 2.7-9.2 mmol K+/g N. It has been suggested that up to 7 mmol K+/g N is required by the anabolic patient. The aim of this study was to determine the effect of a proprietary feed (Triosorbon MCT), containing 6.9 mmol K+/g N, on serum and urinary K in 13 patients requiring nutritional support. Serum electrolytes in all patients and urinary electrolytes in 7 were measured both before feeding commenced and when they had achieved an intake of between 2.4 and 3.0 liter/day (102-127 mmol K+/day) of full strength feed for a period of 1 wk. Ther serum K rose in all patients from 4.2 +/- 0.5 mmol/liter (mean +/- SD) before feeding to 5.1 +/- 0.5 after feeding for 1 wk (p less than 0.001; pair-difference t-test). The daily urinary K excretion rose from 37.8 +/- 24.2 mmol/day to 61.8 +/- 26.6 over the same period (p less than 0.001) The serum urea rose from 4.7 +/- 2.0 mmol/liter to 6.3 +/- 3.2 (p less than 0.05). No significant change was observed in other serum electrolytes, creatinine, or urinary electrolytes. During the whole course of feeding (range 1-11 wk) it was necessary to discontinue Triosorbon in 2 patients whose serum K concentration became elevated to greater than 6 mmol/liter. We conclude that the recommended levels of K intake may be too high and that serum K should be carefully monitored during enteral feeding.     

Analysis of selenium content in commercial dietetic products

Selenium (Se) is largely associated with the protein component of foods. The processing of elemental feeds and artificial formulations used in clinical dietetic practice can, therefore, result in significant losses of Se from these products and the Se status of patients consuming these feeds may be compromised. A selection of commercial formulas typically used for enteral feeding, and for patients with cystic fibrosis, phenylketonuria and maple syrup urine disease were analysed for Se micro-fluorimetrically. Low Se contents were found in all food supplements except for Peptisorbon (0.09 mg Se/2000 kcal) and Clinifeed Protein Rich (0.08 mg Se/2000 kcal) which contained adequate daily Se levels according to the American RDI. The results show that a number of feeds are low in Se, especially those used for patients with cystic fibrosis and maple syrup urine disease. An investigation of the Se status of patients on these formulations may indicate the need for Se supplementation.     

Enteral feeding tube guidewire—another factor in the retrograde contamination of enteral feeding systems?

Background: In vitro enteral feeding systems were used to investigate the effect that withdrawal of the guidewire from the feeding tube has on bacteria ascending from a patients’ stomach or intestine via the feeding tube to the giving set and nutrient container of the feeding system. Methods: Enteral feeding systems were assembled with the feeding tube running into nutrient broth contaminated with Klebsiella aerogenes. The enteral feeding tubes were held in different orientations (horizontal and vertical) to examine the effect in both prostrate and ambulant patients. The guidewire was removed either prior to or after the enteral feeding tube had been inserted into the K. aerogenes broth. Feed was then run through the systems for 24 h, with feed samples being collected from the distal (patient) end of the giving set at 0 and 24 h. Results: After 24 h, 10^3–108 c.f.u. (colony forming units) K. aerogenes/ml were detected in feed samples taken from the distal end of the giving set in systems where the guidewire had been removed after the enteral feeding tube had been inserted into the contaminated broth (both orientations), but K. aerogenes was not detected in samples from systems in which the guidewire had been removed before the end of the tube was inserted into the broth (both orientations). However, when the latter feed samples were enriched (i.e. incubated at 37 °C for a further 24 h to detect if very low levels of bacteria were present in the original sample), 40% of samples from systems with horizontally orientated tubes, and 20% from systems with vertically orientated tubes were positive for the test organism. K. aerogenes was not detected in any samples of feed taken from the nutrient container or just below the drip chamber. Conclusion: The results demonstrate: (i) that bacteria ascend the feeding tube over a 24-h period (retrograde contamination) and (ii) removal of the guidewire can contribute to the colonization of the lumen of the feeding tube and distal end of the giving set with bacteria from a patients’ own flora.     

Bacterial contamination of reconstituted and commercially prepared enteral feeds

Bacterial contamination of two forms of a commercially available nasogastric tube feed has been assessed in 28 patients receiving fine-bore nasogastric tube feeding. A commercially prepared liquid form of the feed was compared with a powdered form which required reconstitution prior to administration. The effect of differing concentrations of feed on bacterial growth was also assessed.No significant differences in bacterial counts were found, irrespective of the form or concentration of feed used. The bacterial counts of all feeds were significantly greater 6–12 h after commencing the feed than at the start of feeding. Contamination from the feed reservoirs and giving sets may be as important as contamination of the feed itself, therefore careful technique is required in the filling of reservoirs and delivery of the feed as well as in the preparation of the feed.     

Enteral nutrition

Enteral nutrition is feeding the gastrointestinal tract either with food, oral supplements or via tube. It is generally safe, easy to administer and free of major complications. The most common problems relate to the tubes themselves, such as blockage and stoma infection.     

Is supplementation with elemental diet feasible in patients undergoing pelvic radiotherapy?

BACKGROUND: Acute gastrointestinal upset occurs in approximately 80% of patients undergoing radiotherapy for pelvic cancers. Underlying changes relate to denudation of the mucosal layer which renders the small intestine vulnerable to additional damage from proteolytic enzymes and bile acids. Severe acute bowel symptoms may predispose to progressive fibrotic and ischaemic changes. Elemental diet given during treatment may reduce acute and chronic bowel symptoms induced by pelvic radiotherapy. METHODS: This study aimed to assess compliance with elemental diet during pelvic radiotherapy. Patients with gynaecological, urological or rectal malignancy undergoing radical or adjuvant pelvic radiotherapy were randomised to one of five groups. Each group was assigned a target quantity of three different elemental sip feeds (Group 1, 20%, Group 2, 50%, Group 3, 75% of calorie requirements taken as E028 extra liquid; Group 4, 50% of calorie requirements taken as E028 extra powder; Group 5, 50% of calorie requirements taken as Emsogen powder). Compliance was assessed using a diary card and weekly assessment. Statistical analyses were conducted on an intention to treat basis. RESULTS: Fifty patients (44 female, six male) mean age 58 yr (95% CI 55-61), were recruited to the study (24 endometrial, 17 cervical, 7 rectal, 1 vulval and 1 bladder carcinoma). Mean weight at baseline was 74.5 kg (95% CI 69-80) and this did not change during treatment. Full compliance was achieved in three patients, all from Group 1. By week 5, only 46% of patients were consuming elemental diet. Post hoc analysis of variance with repeated measures indicated that there were no significant differences in volume of elemental diet consumed between groups (P = 0.937). There was a significant inverse linear relationship between intake of elemental diet and time (P < 0.001). CONCLUSIONS: Different formulations of elemental diet do not influence compliance. Patients are unlikely to be able to consume more than one-third of their calorie requirements in the form of an elemental sip feed. Further investigation is warranted to determine if intervention with this volume of elemental diet is beneficial.     

The potential of Escherichia coli in enteral feeds to cause food poisoning: a study under simulated ward conditions

The growth of Escherichia coli over a period of 8 h under simulated ward conditions was compared in feeding systems containing either Clinifeed ISO or Nutrient Broth. In both, counts increased from 10² to 10⁷ ml^?1. Other systems containing Clinifeed ISO were inoculated with E. coli and sampled over 24 h. At 8 and 16 h the contaminated reservoir was replaced, refilled or replaced together with the gastric drip line. When the reservoir was replaced or refilled it was always recontaminated by residual organisms. Even when the reservoir and drip line were replaced, although the contents of the reservoir were sterile, E. coli was still detected in feed collected from the end of the fine-bore tube. Experiments with varying numbers of E. coli in the inoculum demonstrated that even one organism in the reservoir could, within 16 h, multiply to a level that might be harmful, especially to compromised patients.     

Bacterial contamination and growth in two defined formula diets of different pH

We inoculated partially hydrolysed protein feed of low pH and an intact protein feed of neutral pH with various pathogenic bacteria, and showed that the low pH feed restricted bacterial growth. To study this effect in a clinical setting, 20 malnourished in-patients were randomised prospectively to receive one or other of these feeds. Both formulae were given as a continuous feed via a nasogastric tube, 1,000 ml over 12 h twice daily, using routine hygienic measures. On two occasions significant contamination was demonstrated (Erwinia herbicola and Acinetobacter Iwoffi), both occurring in the intact protein diet. When the bacteria were isolated and transferred to the hydrolysed protein diet, their growth was inhibited. The contamination did not cause clinical complications. The study demonstrates inhibition of microbial growth in a partially hydrolysed protein formula of low pH. This effect may reduce the risk of contamination, and limit infectious complications.     

Home enteral feeding audit 1 year post-initiation

OBJECTIVE To determine the practical problems that families of children on home enteral tube feeds (HETF) experience in the first year post-hospital discharge. METHODS Thirty parents/carers of children (0-16 years) completed a multiple choice/short answer questionnaire by interview 12 months after discharge from hospital. Issues addressed included: home delivery of feed and equipment; pump usage; tube changes; and overnight feeding. RESULTS: The main problems identified were: sleep disturbance (75%); frequent tube dislodgement (46%); tube blockages (41%); inability of some home delivery companies (HDC) to provide all the paediatric special feeds required (43%); and pump inaccuracy (23%). Conclusions Children on long-term HETF and their families experience significant problems with sleep disturbance, tube dislodgement and tube blockage. In addition, accuracy of pumps and obtaining feed and equipment was a source of stress. Dietitians and community nurses urgently need to explore solutions to the common problems associated with overnight feeding. Furthermore, regular home reviews are necessary in long-term HETF to continue to identify and minimize problems.     

The effect of different feeds, including those containing soya-bean products, on the passage of digesta from the abomasum of the preruminant calf.

1. The effects of various factors on rates of flow and composition of digesta leaving the abomasum of preruminant calves were studied. The possible relation of some of these effects to the development of serum antibodies to certain dietary constituents has also been examined. Two situations were distinguished: (a) unsensitized responses, shown by calves receiving milk protein or soya-bean products for the first one or two occasions; (b) sensitized responses, shown by calves receiving certain soya-bean products, after a number of these feeds had been given. 2. For unsensitized calves, the rate of flow of total digesta from the abomasum was greater in the first few hours after a feed consisting of a mineral solution was given, than after cow's milk was given. This difference wasapparently due to differences in the composition of digesta entering the duodenum. Total digesta flows after giving synthetic milk feeds, prepared from different protein sources, were similar to those after cow's milk was given. 3. For sensitized calves, rates of flow of total digesta from the abomasum were greatly affected by the nature of the protein source used in the diet. Soya-bean flour (heated or unheated) generally caused inhibition of flow for some hours after feeding; a soya-bean protein isolate (isoelectric) had a similar but smaller effect, but a soya-bean concentrate (prepared by alcohol extraction of a soya-bean flour) and milk protein had little or no effect. The inhibition, believed to be a sign of more general disorders, appeared to be caused by a factor entering the duodenum which induced a change in the way in which the calf responded, probably as the result of a gastrointestinal allergy. 4. Calves given soya-bean flour or a soya-bean protein isolate (isoelectric) in their diets for several weeks, showed respectively high and low titres of serum antibodies to an antigen prepared from soya-bean flour. Calves given alcohol-extracted soya-bean concentrate had no similar antibodies. 5. In addition to variations in total digesta flow, dietary nitrogen compounds were held up in the abomasum to different extents after different feeds. After a whole-milk feed or a synthetic feed prepared from casein, a slow, steady release of N occurred over at least 9 h. N hold-up after giving soya-bean-containing feeds was slight for the soya-bean flour, but extremely marked for the soya-bean protein isolate (isoelectric). The latter hold-up was followed after several hours by a rapid outflow of N from the abomasum.     

Nursing administration of medication via enteral tubes in adults: a systematic review

Background Enteral tubes are frequently inserted as part of medical treatment in a wide range of patient situations. Patients with an enteral tube are cared for by nurses in a variety of settings, including general and specialised acute care areas, aged care facilities and at home. Regardless of the setting, nurses have the primary responsibility for administering medication through enteral tubes. Medication administration via an enteral tube is a reasonably common nursing intervention that entails a number of skills, including preparing the medication, verifying the tube position, flushing the tube and assessing for potential complications. If medications are not given effectively through an enteral tube, harmful consequences may result leading to increased morbidity, for example, tube occlusion, diarrhoea and aspiration pneumonia. There are resultant costs for the health-care system related to possible increased length of stay and increased use of equipment. Presently what is considered to be best practice to give medications through enteral tubes is unknown. Objectives The objective of this systematic review was to determine the best available evidence on which nursing interventions are effective in minimising the complications associated with the administration of medications via enteral tubes in adults. Nursing interventions and considerations related to medication administration included form of medication, verifying tube placement before administration, methods used to give medication, methods used to flush tubes, maintenance of tube patency and specific practices to prevent possible complications related to the administration of enteral medications. Search strategy The following databases were searched for literature reported in English only: CINAHL, MEDLINE, The Cochrane Library, Current Contents/All Editions, EMBASE, Australasian Medical Index and PsychINFO. There was no date restriction applied. In addition, the reference lists of all included studies were scrutinised for other potentially relevant studies. Selection criteria Systematic reviews of randomised controlled trials (RCTs) and RCTs that compared the effectiveness of nursing interventions and considerations used in the administration of medications via enteral tubes. Other research methods, such as non-randomised controlled trials, longitudinal studies, cohort and case control studies, were also included. Exclusion criteria included studies investigating drug-nutrient interactions or the bioavailability of specific medications. Data collection and analysis Initial consideration of potential relevance to the review was carried out by the primary author (NP). Two reviewers independently assessed study eligibility for inclusion. A meta-analysis could not be undertaken, as there were no comparable RCTs identified. All data were presented in a narrative summary. Results There is very limited evidence regarding the effectiveness of nursing interventions in minimising the complications associated with enteral tube medication administration in adults. The review highlights a lack of high quality research on many important nursing issues relating to enteral medication administration. There is huge scope for further research. Some of the evidence that was identified included that nurses should consider the use of liquid form medications as there may be fewer tube occlusions than with solid forms in nasoenteral tubes and silicone percutaneous endoscopic gastronomy tubes. Nurses may need to consider the sorbitol content of some liquid medications, for example, elixirs, as diarrhoea has been attributed to the sorbitol content of the elixir, not the drug itself. In addition, the use of 30?mL of water for irrigation when administering medications or flushing small-diameter nasoenteral tubes may reduce the number of tube occlusions.     

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.     

Accuracy of home enteral feed preparation for children with inherited metabolic disorders

Background: Many children with rare chronic disorders require home enteral tube feeds (HETF) consisting of multiple modular ingredients. Feeds are often complex and the risk of errors during their preparation is high. The consequences of over‐ or under‐concentration can be critical. The aim of the present prospective observation study was to assess the accuracy, skills and technique of caregivers when preparing and administering HETF. Methods: Fifty‐two HETF patients (median age 7.5 years, range 0.7–18.0 years) with inherited metabolic disorders (IMD) requiring special feeds were recruited. Using observation and a structured questionnaire, a practical assessment of feed preparation and storage by the main caregiver was undertaken by an independent dietitian and nurse in the child’s home, including hygiene practices, accuracy of measuring recipe ingredients, and storage of both ingredients and prepared feeds. Results: The majority (85%; n = 44) of feeds were based on >1 ingredient (median 3; range 1–6). Almost half (48%; n = 25) of caregivers measured feed ingredients inaccurately. Of the 31% (n = 16) using scoops, 31% used incorrect measuring spoons and 25% did not level scoops appropriately. Some 45% (n = 20/44) of carers measured liquid ingredients inaccurately. Hygiene practices during feed preparation were poor, including a lack of hand washing (31%: n = 16) and incorrect storage procedures for unused feed ingredients (56%; n = 29). Conclusions: Practices in the preparation of modular HETF for children with IMD were not ideal. A combination of inaccuracy, poor hygiene, inappropriate storage, and long feed hanging times increases both metabolic and microbial risk. Better education, regular monitoring and the development of ready‐to‐use or preweighed ingredients would be beneficial.     

Comparison of Gravity Flow Rates Between ENFit and Legacy Feeding Tubes

Background: Misconnections between enteral supplies and other access devices have led to significant morbidity and mortality. To reduce misconnections, a standard small‐bore connector has been developed (International Organization for Standards 80369‐8; ENFit). The full impact of transition to this connector is not known, however. Method: Working with major manufacturers and Food and Drug Administration, we obtained ENFit and comparative legacy tubes of variable sizes (low‐profile, 14F, 18F, 20F, and 24F balloon gastrostomies). Gravity enteral feeding was simulated with an empty bolus syringe attached to the feeding tube to be tested. The tube was clamped and filled to the 60‐mL mark with liquid (water, Jevity 1 Cal, Isosource HN, Isosource 1.5 Cal, Two Cal HN, and Nourish). The clamp was released, and time for formula to leave the syringe was recorded. Results: There was no difference in flow rate between the aggregate legacy and ENFit tubes for the low‐profile, 18F, and 20F sizes. The ENFit 14F tubes had a lower flow rate vs the legacy tubes, largely due to the low flow rates seen with the 1 ENFit tube. Similarly, 24F ENFit tubes with some formulas yielded lower flow rates as opposed to legacy. Conclusion: Overall, for the low‐profile, 18F, and 20F sizes, the ENFit tubes had similar flow rates when compared with the legacy tubes. For the 14F and 24F sizes, the flow rate of ENFit tubes was significantly lower, which could result in longer EN delivery for patients who are using these tubes to provide gravity feeding.     

The effect of system design on bacterial contamination of enteral tube feeds

The effect of recent changes in system design on the levels and incidence of bacterial contamination in enteral tube feeds was examined by comparing two different systems.Adult patients who had been identified as requiring enteral tube feeding were allocated to receive sterile, whole protein enteral feed from either 2 x 1000 mL triple foil laminated pouches (Nutrison Standard, Nutrison Pack, Nutricia Ltd, UK) attached to a Flocare 800 pack giving set or from 2 x 1000 mL rigid plastic bottles (Osmolite, Ross Ready-to-Hang, Abbott Laboratories, UK) connected to a Patrol Pump set. Samples of feed from the nutrient containers were sent for microbiological analysis each time the container was changed (12 and 24 h) and samples from the distal ends of giving sets after 24 h.Bacterial contamination was found in a significantly lower number of Nutrison Packs (14/120; 12%) as compared with Ross Ready-to-Hang containers (25/120; 21%) (Fisher's exact test, 1 tailed test, P > or = 0.05). However, both the level and frequency of contamination of the feed samples collected from the distal ends of the giving sets of both types of system were similar to each other but higher than those from the nutrient containers (57/120 contaminated giving sets as compared with 39/240 nutrient containers; P > or = 0.00001). On 32/120 patient days only the giving set samples were contaminated.The results highlight the important role that improvements in system design, such as the use of recessed spikes on giving sets have in reducing the risk of bacterial contamination of enteral tube feeds introduced due to faulty handling procedures, and further implicate retrograde spread of the patients' own flora as a source of contamination in the giving set.     

Enteral nutrition in the cardiothoracic intensive care unit: challenges and considerations

Cardiovascular disease is a common preexisting condition among hospitalized patients. Acute myocardial infarction and cardiac surgery account for 2 of the most common reasons patients are admitted to the intensive care unit. Determining how and when to feed these patients is a constant challenge presented to nutrition support practitioners. Enteral nutrition has emerged as the preferred route of feeding particularly in critical illness. By providing enteral nutrition instead of parenteral nutrition, the natural physiologic pathway is being followed and gut immunity preserved. However, obstacles such as upper gastrointestinal intolerance, hypoperfusion vasopressor support, and glycemic control make the task of initiating feeds a challenge. Once a patient has successfully tolerated feeds, the nutrition support clinician must still determine how much to feed and if specialty formulas such as those containing omega-3 fatty acids are beneficial for their patient. The purpose of this review is to present recent research on the feeding challenges in the critical care population with a focus on the cardiothoracic population and an emphasis on improving patient outcomes.