Effect of enteral feeding bag composition and freezing and thawing upon vitamin stability in an enteral feeding solution

The effect of enteral feeding bag composition and freezing and thawing upon the stability of riboflavin and vitamins A and E in an enteral feeding solution was tested. Feeding bags composed of either polyvinyl chloride or polyethylene were filled with an enteral feeding solution. The samples were frozen for 3 months, thawed in warm water, and allowed to stand in room temperature for 12 hr. Samples for vitamin analysis were obtained prior to freezing, upon thawing, and at 12 hr after thawing. No significant differences in vitamin stability due to bag composition or time were seen. These results support the viability of the concept of mixing large batches of enteral feeding solution, and freezing aliquots in individual feeding bags for later use.     

Clearing obstructed feeding tubes

This is a report of an in vitro study evaluating the ability of six solutions to dissolve clotted enteral feeding, which can cause feeding tube occlusion. The following clotted enteral feeding products were tested: Ensure Plus, Ensure Plus with added protein (Promod 20 g/liter), Osmolite, Enrich, and Pulmocare. Clot dissolution was then tested by adding Adolf's Meat Tenderizer, Viokase, Sprite, Pepsi, Coke, or Mountain Dew. Distilled water served as control. Dissolution score for each mixture was assessed blindly. Best dissolution was observed with Viokase in pH 7.9 solution (p less than 0.01). Similar results were obtained when feeding tube patency was restored in eight in vitro occluded feeding tubes (Dobbhoff, French size 8) by using first Pepsi (two/eight successful) and then Viokase in pH 7.9 (six/six successful). We also report our experience in the first 10 patients with occluded feeding tubes using this Viokase solution injected through a Drum catheter into the feeding tube. In seven patients, this method proved to be successful, and the reasons for failure in three patients include a knotted tube, impacted tablet powder, and a formula clot fo 24 hr duration and 45 cm in length.     

Microbial contamination of enteral feeding formulas and diarrhea

Twenty-five medical and surgical patients receiving liquid ready-to-use sterile enteral formulas were evaluated prospectively to investigate the relation of diarrhea to serum albumin level, total lymphocyte count, delayed hypersensitivity to purified protein derivative, antibiotic therapy, administration rate and site of enteral formula, and microbial contamination of enteral feeds. Formulas were administered to 6 patients with hang times of up to 6 h by pump-assisted continuous drip and to 19 patients with hang times of up to 3 h as a bolus feeding. Samples of formulas for microbial culture were obtained aseptically before and after feeding on the first and eighth day of the study period. The incidence of microbial contamination of the formula before and after feeding was 1 of 49 samples (2.0%) and 10 of 48 samples (20.8%), respectively. There were 2 patients with diarrhea, which occurred on the second day. Formula samples from 2 patients (100%) with diarrhea and 2 samples from 23 patients (8.7%) without diarrhea were contaminated with 10(4) cfu/mL or more, respectively. A significant difference (P = 0.04) was detected between the two groups. The other factors studied showed no significant association with the incidence of diarrhea. In conclusion, contaminated formula appears to play a significant role in the etiology of diarrhea in patients receiving enteral feeding.     

Effect of pH on the equilibrium dialysis of phenytoin suspension with and without enteral feeding formula

Significant decreases have been reported in phenytoin absorption when the suspension is combined with continuous enteral feedings. Several theories for this interaction have been proposed including binding of phenytoin to the protein constituents of the enteral formula, phenytoin binding to the calcium in the enteral formula, and inadequate dissolution of the suspension when delivered with the enteral formula due to the high pKa of phenytoin and the acidic nature of the enteral formula. We therefore evaluated the effects of pH levels 2.0, 3.5, 6.0, and 8.0 on the interaction of phenytoin suspension with enteral formula (Osmolite) with equilibrium dialysis using a Spectra/Por 1 (MWCO 6000-8000) molecularporous dialysis membrane. Phenytoin concentrations in the dialysis membrane (internal phase) mimicked the expected stomach concentrations of a 100-mg dose administered in an adult stomach containing 200 ml of gastric fluid. External phase buffers were sampled at 0.5, 1.0, 2.0, 4.0, 8.0, 12.0, and 24.0 hr after the start of the dialysis. The phenytoin concentrations in the external phase were compared between buffer alone or buffer combined with enteral formula at the same pH and time intervals. With pH 2.0 and 3.5 the enteral formula formed an aggregate with suspension whereas no aggregate was formed with pH 6.0 and 8.0. The phenytoin concentrations with pH 2.0 were 26% to 44% lower and with pH 3.5 were 11.5 to 27% lower when phenytoin suspension was combined with enteral solution. However, at 24 hr there was no difference between the two conditions with both pH 2.0 and 3.5.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of sites of bacterial contamination in an enteral feeding system

BACKGROUND: Contamination of enteral feedings is an often overlooked source for bacterial infection in the intensive care unit. A new 1-L enteral feeding system with minimal chances of touching critical areas (Nutrison Pack) was compared with routinely used 0.5-L glass bottle systems. METHODS: Patients admitted to intensive care were randomized to Pack or glass bottle feeding systems. Cultures were taken from the delivery sets 5 times during the day and from feeding containers and different sites of the system after 24 hours. RESULTS: Bacteria were present in 3 of 112 glass bottles and in 2 of 95 Pack bags. True bacterial contamination (defined as >10(2) colony-forming units/mL, with same bacteria also present in the delivery set) was found in none of the Packs with a 12-h (69 Packs) or a 24-h (26 Packs) hanging time and in only 1 of the glass bottles with a hanging time of 24 hours, which exceeded the advised hanging time of 8 hours. In contrast, the contamination rate of delivery sets was 48%, with increasing bacterial counts over the day and 4 subsequent days. Bacteria mainly belonged to the group of potentially pathogenic bacteria (Enterobacteriaceae and Pseudomonaceae). They likely originated from throat, lungs, and stomach and grew into and along feeding tubes upwards until they reached the delivery set. CONCLUSIONS: Prolonged hanging times of Pack bags were safe with respect to bacterial contamination. However, the bacterial safety of enteral feedings is more likely to be endangered by the endogenous route of contamination rather than exogenous contamination, as high bacterial counts were found in feeding tubes and delivery sets as a result of retrograde growth.     

Microbial contamination of enteral feeding solutions in a community hospital

Seven related studies were done to estimate the type and amount of contamination that occurred in nutrient feeding solution when administered according to procedure in a community hospital. The initial study was done in a simulated nonclinical setting with select technicians monitoring for gavage systems delivering a commercially prepared nutrient feeding solution. The solution remained sterile over 48 hr. In the second study, various nurses maintained the enteral feeding simulations unaware of the objective of study. Significant contamination was found, but a decrease occurred when the study was duplicated and the nurses were made aware that contamination was the issue being studied. The subsequent study had all gavage equipment in clinical use in the hospital on a given day cultured for microbial contamination. Significant contamination was present and did not decrease when the study was duplicated following inservice training. Suggestions for standards of care are made.     

Problems with the re-use of enteral feeding systems—a study of the effectiveness of a range of cleaning and disinfection procedures

Although many manufacturer's state that their systems are 'single-use only', some authors are now recommending that enteral feed delivery systems can be re-used, particularly in the home, in order to reduce the expense of enteral feeding.
The purpose of this study was to evaluate the effectiveness of a range of currently recommended cleaning and disinfection procedures in removing bacteria from five commonly used enteral feeding systems. The systems used were, a collapsible, top-fill reservoir with integral giving set, a plastic enteral nutrition bag with side port and integral giving set, and three different types of rigid plastic reservoirs with separate giving sets.
The systems were filled with 1000-ml portions of feed experimentally contaminated with either Klebsiella aerogenes or Escherichia coli and the feed perfused through the systems for 15 h; viable counts increased from 10²-^-10³ to 10⁷-^-10⁹ cfu ml^-1. The systems were then cleaned by a range of methods including rinsing and/or immersing them in sterile water, sterile water and detergent, and/or disinfection with hypochlorite solutions. When the systems were refilled with sterile feed it was found that residual bacteria in the systems multiplied to yield levels ≤10⁹ cfu ml^-1 after 15 h.
The results of the present study demonstrate that none of the methods tested can be recommended as being totally effective in removing bacteria from contaminated systems.     

Early initiation of enteral feeding after percutaneous endoscopic gastrostomy tube placement.

Enteral feeding through the percutaneous endoscopic gastrostomy (PEG) tube is usually initiated about 12 to 24 hours after insertion of the tube. There have been earlier studies evaluating the efficacy of early initiation of enteral feedings that had encouraging results. However, delayed initiation of feeding following PEG placement continues to be practiced widely. We believe that feeding can be done earlier without any increase in associated morbidity or mortality and with obvious reduction in the need for parenteral nutrition and healthcare costs. We evaluated a protocol to initiate enteral nutrition 4 hours after the PEG tube insertion with subsequent discharge of the outpatients on the same day. We conducted a prospective study to assess the efficacy of early initiation of PEG feeding. We enrolled 77 patients in our study who were having PEG tubes placed for enteral feeding. Only patients who had a PEG placed for gastric venting procedures were excluded from our study. During the course of our study, no patient had to be excluded for the latter reason. Patients were evaluated by the physician performing the procedure, 4 hours after the tube was inserted. Their vital signs were checked, and a thorough abdominal examination was performed. Minimal tenderness around the PEG site was the most frequent finding. Otherwise, all the patients had a benign abdominal examination. The tube was flushed with 60 mL of sterile water. Following the examination, orders were given to restart the feedings. These patients were followed for a 30-day period to evaluate complications associated with PEG tube placement and early initiation of PEG feeding. There was one case of aspiration pneumonia (1.3%) and one death that was attributed to the underlying disease out of our 77 patients. Early initiation of enteral feeding after PEG tube placement can be successfully completed with a systematic protocol and close observation. Not only was this protocol found to be safe, it can also have significant cost savings by eliminating the need for inpatient hospitalization for the procedure.     

Microbial contamination of enteral feeding sets used in the home of pediatric patients.

Bacterial contamination of enteral feeding sets has been well documented in studies of patients. Much of the literature on this subject validates problems with manipulations of the feeding sets such as mixing formula and handwashing by the caregiver. Rinsing and storing of the set could also have serious implications in the amount of contamination. There is currently no standard recommending the length of time for use of enteral feeding sets for home care patients, particularly in children. Nine homecare patients with ages ranging between 1 and 15 years participated in this study. Cultures of the formula in the feeding set were obtained at zero hours with a new set, and after 24 and 48 hours. The caregivers prepared and administered the formula in their usual manner. Clinical data were collected for 10-14 days before the samplings and for 7 days afterward. Data included weights before, during, and after the culture collection period. Medications, stools, and emesis were recorded during this timeframe. It is difficult to draw statistically significant conclusions based on the small sample size of this study. There was an undesirable level of contamination at 48 hours of enteral feeding set use that was not present at 24 hours in 2 of the patients (22.2%). Neither of these children had diarrhea, vomiting, or other clinical changes, but both showed a small weight loss. The majority of the patients (77.8%) demonstrated that using sets for 48 hours did not increase the amount of contamination.     

Prevention of yeast translocation across the gut by a single enteral feeding after burn injury

Recently, burn injury has been shown to facilitate the ability of enteric Candida albicans (CA) to penetrate the gut epithelium and translocate to the mesenteric lymph nodes (MLN) during the first 24 hr after injury. Guinea pigs were given 3 X 10(10) CA intragastrically before inflicting a 50% burn to determine if a single enteral feeding could affect CA translocation to the MLN. A bolus infusion (20 kcal/kg, 12 ml in volume) of liquid meal, consisting of 68% carbohydrate, 20% protein, and 12% lipid, was administered either at 3-hr or 12-hr postburn. Control groups received no food or a similar amount of saline by bolus infusion. All animals were allowed water ad libitum until 24-hr postburn when their MLN and intestinal segments were harvested for enumeration of viable CA. Blood was also collected for determination of serum IgG, C3, cortisol, and albumin. Compared to nonfeed animals, those with a single enteral feeding at 12-hr postburn had reduced numbers of CA translocating to the MLN (970 +/- 220 vs 7,120 +/- 2,130 CFU/g, p less than 0.02) and colonizing in the ileum (27,000 +/- 6,770 vs 104,000 +/- 23,550 CFU/g, p less than 0.01). Bolus feeding at 12 hr was associated with a lower cortisol level (237 +/- 55% of normal controls) than bolus feeding at 3 hr (310 +/- 58, p less than 0.02) or the nonfed group (326 +/- 66, p less than 0.01). Regardless of dietary treatment, serum cortisol levels correlated positively with the extent to which CA translocated to the MLN and negatively with C3 levels.     

Effect of enteral formula infusion rate, osmolality, and chemical composition upon clinical tolerance and carbohydrate absorption in normal subjects

It is a common clinical practice to initiate enteral hyperalimentation using low flow rates or diluted formula. These adjustments are made in an effort to minimize patient intolerance. Using complex and elemental enteral formulas, we investigated whether various flow rates or osmolalities effected clinical intolerance or carbohydrate malabsorption in 20 healthy volunteers. Our infusion rates ranged between 50 and 150 kcal/hr and the osmolalities ranged between 325 and 690 mOsm/Kg of water. Even at the maximal flow rate and osmolality, our results show that both types of enteral formulas were well tolerated as assessed by the frequency of abdominal pain, bloating, passage of rectal gas and stooling. No carbohydrate malabsorption was detected as measured by breath hydrogen. In well nourished subjects, our findings do not support the common clinical practice of initiating alimentation with low flow rates or diluted formula.     

Beta-carotene in tube feeding

The supplementation of an enteral feeding formula on soya-basis specially designed for geriatric patients with 1,5 mg to 2 mg beta-carotene per day increases its corresponding plasmatic concentration from 20 mcg/L to normal to optimal levels near 500 mcg/L. This intake is much lower than the proposed safe intake of 6-20 mg beta-carotene per day. A close incorporation of beta-carotene in the lipid moiety of the ready-to-use formula might increase its bioavailability. The other anti-oxidative vitamins A and E remain to their respective normal levels at a supplemental daily intake of 2500 IU vitamin A and 12,5 mg vitamin E. The new enteral feeding formula for geriatric patients seems to cover their global nutritional needs.     

Re-use of enteral feeding tubes--a potential hazard to the patient? A study of the efficiency of a representative range of cleaning and disinfection procedures.

Some hospitals and manufacturers are now recommending that patients (particularly those on home enteral feeding) remove and re-insert their tubes on a daily basis. This study was carried out to evaluate the effectiveness of a representative range of currently used cleaning procedures in removing bacteria from the lumina of these tubes. One thousand-ml portions of feed experimentally contaminated with 10(2)-10(3) Klebsiella aerogenes ml(-1) were perfused through three types of commonly used polyurethane enteral feeding tubes for 15 h. The tubes were then cleaned by a range of methods including rinsing them with sterile water, sterile water and detergent and/or disinfection with hypochlorite solution. A further 1000-ml sterile feed was then perfused through the tubes for 15 h and it was found that residual organisms in the tubes multiplied to yield levels of 10(6)-10(9) colony-forming units (cfu) ml(-1) in the feed collected from the distal ends of the tubes after 15 h. It is concluded that none of the cleaning methods tested can be recommended as being totally effective in removing bacteria from the lumina of contaminated tubes.     

Inadvertent intravenous administration of enteral diet

Needle catheter jejunostomy feedings were instituted in a 64-yr-old man on postoperative day 1 following subtotal gastrectomy for carcinoma of the antrum. Several days later, the enteral tube catheter was inadvertently connected to the patient's peripheral intravenous cannula which resulted in the intravenous administration of the enteral formula solution. The administration was stopped immediately when recognized, but 4 hr later the patient became febrile, hypotensive, and tachycardic. Cultures from the enteral solution demonstrated Streptococcal viridans and yeast; the patient's blood cultures similarly demonstrated S. viridans. Broad spectrum antibiotics, hemodynamic monitoring, and intravascular support with crystalloid solutions resulted in a favorable outcome. Prevention of the complication could be assured by adopting luer connectors for enteral feeding sets which cannot be connected to intravenous cannulas. Until these are available, the addition of methylene blue to the tube feeding formula or utilization of color coded distal connecting tubing may prevent accidental intravenous administration of tube feeding formulas. The potential for this complication must be recognized by those dealing with enteral feeding.     

Continuous nasogastric tube feeding: monitoring by combined use of refractometry and traditional gastric residual volumes

BACKGROUND & AIMS: Traditional use of gastric residual volumes (GRVs) is insensitive and cannot distinguish retained enteral formula from the large volume of endogenous secretions. We designed this prospective study to determine whether refractometry and Brix value (BV) measurements could be used to monitor gastric emptying and tolerance in patients receiving continuous enteral feeding. METHODS: Thirty-six patients on continuous nasogastric tube feeding were divided into two groups; patients with lower GRVs (<75 ml) in Group 1, patients with higher GRVs (>75 ml) in Group 2. Upon entry, all gastric contents were aspirated, the volume was recorded (Asp GRV), BV measurements were made by refractometry, and then the contents were reinstilled but diluted with 30 ml additional water. Finally, a small amount was reaspirated and repeat BV measurements were made. Three hours later, the entire procedure was repeated a second time. The BV ratio, calculated (Cal) GRV, and volume of formula remaining were calculated by derived equations. RESULTS: Mean BV ratios were significantly higher for those patients in Group 2 compared to those in Group 1. All but one of the 22 patients (95%) in Group 1 had a volume of formula remaining in the stomach estimated on both measurements to be less than the hourly infusion rate (all these patients had BV ratios <70%). In contrast, six of the 14 patients in Group 2 (43%) on both measurements were estimated to have volumes of formula remaining that were greater than the hourly infusion rate (all these patients had BV ratios >70%). Three of the Group 2 patients (21%) whose initial measurement showed evidence for retention of formula, improved on repeat follow-up measurement assuring adequate gastric emptying. The remaining five patients from Group 2 (35%) had a volume of formula remaining that was less than the hourly infusion rate on both measurements. The pattern of Asp GRVs and serial pre- and post-dilution BVs failed to differentiate these patients in Group 2 with potential emptying problems from those with sufficient gastric emptying. CONCLUSIONS: Refractometry and measurement of the BV may improve the clinical utilization of GRVs, by its ability to identify the component of formula within gastric contents and track changes in that component related to gastric emptying.     

A nonelemental versus an elemental diet for early postoperative enteral feeding by needle catheter jejunostomy

In a prospective randomised study the use of an elemental versus a nonelemental diet for early postoperative enteral feeding by needle catheter jejunostomy was investigated. After extensive gastrointestinal surgery, 25 patients received an elemental and 24 patients a nonelemental diet. The incidence of diarrhoea, the effects of the feeding and the costs were evaluated. The occurrence of diarrhoea was observed more frequently in the elemental diet group (14 25 ) compared to the nonelemental diet group (7 24 ), although this difference was statistically not significant (p > 0.05). No difference was found between the two groups in postoperative restoration of total protein and serum albumin levels and the extent of the postoperative weight loss. The costs showed a clear difference: the nonelemental diet was three times cheaper than the elemental diet. For early postoperative enteral feeding by needle catheter jejunostomy we therefore recommend the use of a nonelemental diet.     

Enteral tube feeding in a cohort of chronic hemodialysis patients.

Malnutrition affects up to half of all chronic dialysis patients and is an important predictor of mortality, but the efficacy of interventions designed to improve the nutritional status of dialysis patients has been poorly studied. Specifically, although enteral tube feeding is often cited as an important option in the treatment of malnourished dialysis patients, there are few studies examining the effectiveness and complications of enteral tube feedings in adults on dialysis. We performed a retrospective analysis of a small cohort (n = 10) of chronic hemodialysis patients who received enteral tube feeding as all or part of their nutrition between January 1 and May 1, 1999, with follow-up through May 1, 2000, to assess the efficacy and complications of enteral tube feeding. Six patients received feeding via a peritoneoscopically placed (PEG) tube, 3 via nasogastric (NG) tube, and 1 patient was switched from PEG to NG feeding after an exit site infection developed at her PEG site. Seven patients received enteral feeding because of swallowing difficulties occurring after a cerebrovascular accident. Four patients were fed via enteral tube temporarily (相似文献   

Hormonal response to enteral feeding and the possible role of peptide YY in pathogenesis of enteral feeding-related diarrhoea

Diarrhoea is a common complication of enteral feeding. Previous studies have demonstrated a secretion of water and electrolytes in the ascending colon during intragastric but not intraduodenal enteral feeding. The cause of this secretion is likely to be neurohumoral in origin. This study was designed to examine the hormonal responses to enteral feeding. In vivo segmental colonic perfusion studies were undertaken. Before and at hourly intervals during these studies serum was taken for estimations of neurotensin (NT), pancreatic glucagon (PG), peptide YY (PYY) and vasoactive intestinal polypeptide (VIP). During fasting there was a median ascending colonic absorption of water in all groups. During feeding there was a net secretion in the ascending colon in both gastric groups and in the high load duodenal group, but not in the low load duodenal group. During these studies the PYY levels remained unchanged from fasting in the low and high load gastric groups. In the low and high load duodenal groups the PYY levels increased. The NT levels increased only in the high load duodenal group. There were no other changes in NT or in PG or VIP levels either between fasting and feeding, or between the gastric and duodenal groups. PYY is known to stimulate intestinal absorption. The absence of a rise during intragastric feeding may be important in the underlying mechanisms of enteral feeding-induced colonic secretion and hence enteral feeding-related diarrhoea.     

Bacteriological safety of closed enteral nutrition delivery system.

One of the most commonly reported side effects of enteral tube feedings is diarrhea, at times attributed to the bacterial contamination of tube feedings. A closed enteral delivery system has recently been devised. It consists of a cardboard Tetrapack containing the sterile enteral nutrition formula and and independent sterile administration set; together these constitute a closed Tetrapack-administration set enteral delivery system. The bacteriological safety of this system was evaluated in vitro under controlled laboratory conditions in a series of studies. There was no or bacteriologically insignificant bacterial contamination of the enteral nutrition formula, even with repeated use of one administration set for multiple containers over 24 h. Bacteriological growth in the enteral nutrition formula was directly related to the duration of the hanging time of a Tetrapack container. No bacterial growth occurred with hanging times less than 18 h; insignificant bacterial growth occurred by 24 h. A progressive time-related increase in bacterial growth occurred between 24 and 48 h. Our data indicate that the newly developed closed Tetrapack-administration set enteral delivery system is, and will remain, bacteriologically sterile if each Tetrapack container is allowed to hang for no longer than 24 h.     

Metabolic effects of arginine addition to the enteral feeding of critically ill patients.

BACKGROUND: Some studies have suggested that the addition of arginine to enteral feeding solutions may improve outcome in critically ill patients, but the mechanism is incompletely explained. In particular, the availability and utilization of arginine administered enterally is not well defined. METHODS: This prospective, randomized, double-blind, placebo-controlled study performed in a Department of Medicosurgical Intensive Care included 51 patients likely requiring long-term enteral feeding. Thirty-seven patients (57 +/- 7 years, SAPS II 33 +/- 6) completed the 7-day study, of whom 20 received the formula enriched with free arginine (6.3 g/L) and 17 received an isocaloric and isonitrogenous control solution. Arginine absorption was assessed from plasma arginine concentrations in serial samples. Three pathways of arginine utilization were explored: (1) the production of nitric oxide, assessed by the plasma concentration of nitrite/nitrate (NOx) and citrulline, and 24-hour urinary excretion of NOx; (2) the protein turnover, estimated by the phenylalanine concentrations; and (3) the activity of arginase, reflected by the ornithine concentration. RESULTS: The plasma concentrations of arginine and ornithine increased in the group fed with the enriched formula (from 55 +/- 9 micromol/L to 102 +/- 9 micromol/L and from 57 +/- 7 to 135 +/- 11 micromol/L, respectively, p < .05), but not with the control formula. There was no difference between groups in either NO production or phenylalanine concentration. CONCLUSIONS: Supplemental arginine in enteral feeding is readily absorbed, and mainly metabolized into ornithine, presumably by the arginase enzyme.