Enteral alimentation: administration and complications

Intensive nutrition in acute lung injury: a clinical trial (INTACT)

BACKGROUND

Despite extensive use of enteral (EN) and parenteral nutrition (PN) in intensive care unit (ICU) populations for 4 decades, evidence to support their efficacy is extremely limited.

METHODS

A prospective randomized trial was conducted evaluate the impact on outcomes of intensive medical nutrition therapy (IMNT; provision of >75% of estimated energy and protein needs per day via EN and adequate oral diet) from diagnosis of acute lung injury (ALI) to hospital discharge compared with standard nutrition support care (SNSC; standard EN and ad lib feeding). The primary outcome was infections; secondary outcomes included number of days on mechanical ventilation, in the ICU, and in the hospital and mortality.

RESULTS

Overall, 78 patients (40 IMNT and 38 SNSC) were recruited. No significant differences between groups for age, body mass index, disease severity, white blood cell count, glucose, C-reactive protein, energy or protein needs occurred. The IMNT group received significantly higher percentage of estimated energy (84.7% vs 55.4%, P < .0001) and protein needs (76.1 vs 54.4%, P < .0001) per day compared with SNSC. No differences occurred in length of mechanical ventilation, hospital or ICU stay, or infections. The trial was stopped early because of significantly greater hospital mortality in IMNT vs SNSC (40% vs 16%, P = .02). Cox proportional hazards models indicated the hazard of death in the IMNT group was 5.67 times higher (P = .001) than in the SNSC group.

CONCLUSIONS

Provision of IMNT from ALI diagnosis to hospital discharge increases mortality.

Strategies to manage gastrointestinal symptoms complicating enteral feeding

Diarrhea and abdominal distension are common complications associated with enteral feeding. Often the cause is unknown, the enteral formula is blamed and changes to the mode of delivery or formula are instituted. However, the evidence base for many strategies used is limited. Altering the osmolality and temperature of the formula and/or the rate of infusion are commonly practiced but evidence for their benefit is largely anecdotal. Preventing microbial contamination of the feed is important and clear guidelines exist to achieve this. The formulation itself can be modified. While the addition of fiber is well supported theoretically, outcome data are less convincing. Avoidance of osmotically active, poorly absorbed short-chain carbohydrates in the formula (often used as the major carbohydrate source) is a new tactic to minimize diarrhea. It has compelling theoretical support, but requires further investigation. A methodical clinical approach to gastrointestinal complications of enteral feeding is warranted and an algorithm for management is proposed.

Enteral nutrition and enteral tube feeding. Review of the evidence

Improvements in delivery systems for enteral feeding, in formulas, and in the understanding of complications have made the technology for enteral feeding easy to apply. Adequate nutrients can be delivered, and individual tolerance for feeding is acceptable. The remaining question is when to apply the technology. Formula selection should be as simple as possible. Aspiration and other early complications are a serious risk and are not diminished by route of feeding. Long-term enteral feeding is associated with a high complication rate, with high mortality, and may not be effective.

Beneficial effect of a bile acid resin binder on enteral feeding induced diarrhea

OBJECTIVES

Diarrhea is a complication of enteral feeding, occurring in up to 68% of critically ill patients. We hypothesized that prolonged fasting results in abnormal bile acid homeostasis. Subsequent enteral feeding then causes a relative luminal excess of bile acids, which leads to choleretic diarrhea. Hence, diarrhea induced by enteral feeding should improve with the use of a bile acid binding agent, such as Colestid Granules.

METHODS

We evaluated the effect of Colestid on enteral feeding-induced diarrhea in a double-blind placebo-controlled study. Nineteen patients who were nil per os (NPO) for 5 days before initiation of enteral feeding were enrolled in the study and treatment continued for 7 days. The severity and frequency of diarrhea were quantified. Fecal bile acids were measured enzymatically. Stool nutrient loss was measured by fat extraction, microkjeldahl determination of nitrogen, and bomb calorimetry of dried fecal specimens.

RESULTS

Enteral feeding resulted in a high frequency of diarrhea (95%) at some time during the observation period. The majority of episodes of diarrhea in both groups were of low volume. Colestid significantly decreased the prevalence and severity of diarrhea. Colestid had no significant effect on fecal calorie or nutrient losses. The average bile acid concentration in the stool increased significantly after enteral feeding.

CONCLUSION

Enteral feeding-induced diarrhea is, at least in part, due to malabsorption of bile acids. The bile acid resin binding agent Colestid improves diarrhea induced by enteral feeding.

Grains or veins: is enteral nutrition really better than parenteral nutrition? A look at the evidence

BACKGROUND

Enteral nutrition is said to be better than parenteral nutrition for providing nutrition support to humans.

PURPOSE

To assess the literature documenting the assertions that enteral nutrition is superior to parenteral nutrition with respect to cost, safety, physiology, intestinal structure and function, bacterial translocation, and outcome.

DATA IDENTIFICATION

Sources included MEDLINE search, personal files, and references from human comparative studies of enteral vs parenteral nutrition.

STUDY SELECTION

The goal was to include all human studies directly addressing questions of comparative efficacy of enteral and parenteral nutrition. Emphasis was given to prospective randomized controlled studies where available. Retrospective comparisons were not included.

DATA EXTRACTION

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

RESULTS OF DATA SYNTHESIS

Enteral nutrition appears to be less expensive than parenteral nutrition, but new economic analyses are needed given the newer aggressive access techniques for enteral nutrition. Enteral nutrition is associated with meaningful morbidity and mortality. The little comparative data existent suggest no differences in safety. Comparative studies of physiology and metabolism as well as comparative and noncomparative studies of intestinal function and structure do not support putative advantages of enteral nutrition. There is no evidence that enteral nutrition prevents bacterial translocation in humans. Enteral nutrition probably reduces septic morbidity compared with parenteral nutrition in abdominal trauma. Otherwise, there is no evidence that enteral nutrition consistently improves patient outcome compared with parenteral nutrition.

CONCLUSIONS

With the exception of decreased cost and probable reduced septic morbidity in acute abdominal trauma, the available literature does not support the thesis that enteral nutrition is better than parenteral nutrition in humans.

Aspiration-Induced Pulmonary Injury

Pulmonary aspiration of gastric contents can cause a spectrum of sequelae that spans from relatively minor to rapidly lethal disease. To emphasize the extent of this spectrum and to encompass both noninfectious complications and infection, we use the term “aspiration-induced pulmonary injury” rather than “aspiration pneumonia.” In this article we review the relevant literature, focusing on more recent insights into the pathogenesis of lung injury, the natural history of aspiration, risk factors, the relationship between aspiration and infection, and recommendations for management. The relevance to human disease of studies using intra-airway acid instillation in animals is questioned. We discuss the difficulties in predicting the clinical course after aspiration. We identify risk factors for aspiration-induced pulmonary injury that are commonly encountered in the intensive care unit, and discuss in detail factors of special interest to the intensivist, including the impact of tracheal intubation; the effects of enteric intubation, particularly the comparison between pre- and postpyloric routes of enteric feeding administration; and the relative risks associated with particular feeding protocols. We conclude with recommendations regarding treatment and prevention strategies.

Nasogastric and percutaneous endoscopic gastrostomy feeding in head and neck cancer patients receiving radiotherapy treatment at a regional oncology unit: a two year study

The aim of this prospective two year study was to compare the outcome of two methods of nutritional support, namely nasogastric [NG] and percutaneous endoscopic gastrostomy [PEG] feeding implemented for head and neck cancer patients unable to maintain their nutritional status whilst receiving radiotherapy treatment at a regional oncology unit. The nutritional requirements of the 100 patients included in the study were calculated and an enteral feeding regime implemented to ensure the nutritional requirements of each individual patient were met. Any changes in the weight and body mass index [BMI] of each patient during the study period were documented. The method of delivery, composition of feed and duration of nutritional support of each feeding method were determined. The feeding methods were found to be equally effective at maintaining body weight. Patients with NG tubes in situ were more frequently prescribed a standard 1 kcal/ml feed administered via an enteral feeding pump, whereas patients with PEG tubes in situ were more frequently prescribed a high energy 1.5 Kcal/ ml feed administered by the bolus method. A number of advantages are associated with PEG feeding including greater mobility, cosmesis and quality of life. Evidence indicates the outcome of radiotherapy treatment is not as favourable if interrupted, therefore, it is essential PEG tubes are sited prior to commencing treatment, illustrating the necessity for dietetic intervention for every patient to be addressed and incorporated into the treatment plan on diagnosis of head and neck cancer before definitive management commences.

Esophageal bezoar resulting from enteral feedings

Esophageal bezoars are rare but are known to occur in patients with structural or functional abnormalities of the esophagus. Additionally, sucralfate and casein containing enteral feeding formulas have been implicated in the formation of esophageal bezoars, particularly in the setting of decreased esophageal pH. We present a case in which a patient with functional impairment of the esophagus related to myasthenia gravis developed an esophageal bezoar. Gastroesophageal reflux, altered esophageal pH, and direct instillation of feeding formula through a rent in the feeding tube were additional factors likely leading to bezoar formation in this patient. Endoscopic examination revealed puttylike material consistent with coagulated enteral feeding formula. An esophagram demonstrated a large bezoar filling the middle and distal thirds of the esophagus. The conditions predisposing to bezoar formation and the proposed mechanisms are discussed. We also summarize the reported cases of esophageal bezoars related to enteral feeding formula, sucralfate, or both.

Importance of fungus colonization in failure of silicone rubber percutaneous gastrostomy tubes (PEGs)

Silicone rubber PEG tubes or replacements were recovered from 111 patients and examined for blockage, dilatations, tears, breaks, or loss of elasticity. All irregularities were stained and examined for fungus using lactophenol cotton blue stain. The intraabdominal portion of the PEG failed from obstructions, loss of elasticity, or tears related to fungus colonies in 36% of cases. An additional 34% were colonized with fungi but did not fail. On frozen section, the fungus invaded the wall of the tubing. The extraabdominal PEG tubing failed from fungi in 12, and 10 additional tubes had colonizations. Nine tubes had distal clogging with crystalline material that is believed to arise from medication. Fungus tube failure occurred in 37% of the tubes in place 250 days and in 70% of tubes in place 450 days. Fungus is an important cause of PEG failure; recommendations are provided to maintain tube patency.

Diarrhea induced by enteral feeding

Diarrhea is reported as a major complication of enteral feeding. Recent studies show that there is a staggering amount of confusion in defining diarrhea in this setting. This causes major problems both in estimating the incidence of diarrhea, as well as determining its clinical impact. In many cases, careful review of the patients' records and evaluation of the diarrhea may lead to its accurate diagnosis and treatment. The frustration involved in the management of these patients may lead investigators to measure quantitatively the patient's fecal output and to come up with a standardized definition of diarrhea. We describe here three cases that show various forms of enteral feeding-induced diarrhea. Subsequently we will review the important issues regarding the definition of related diarrhea and attempt to understand its pathogenesis.

Effect of dietary oat and soy fiber on bowel function and clinical tolerance in a tube feeding dependent population

OBJECTIVE

The role of fiber in tube feeding products has not clearly been defined. While some studies suggest that fiber can increase stool weight and bowel transit time in acutely ill patients, there is less information in stable patients receiving chronic enteral nutritional support.

DESIGN

Using a crossover study design, we investigated the effect of 28.8 g/day of a 50% soy and 50% oat fiber combination in 10 medically stable residents of a chronic care facility. Subjects were randomized to initially receive 10 days of either Isocal HN or Ultracal, which are identical in composition except Ultracal contains 14.4 g/L of fiber. After the first 10-day study, subjects underwent a washout followed by a second 10-day study using the other product. Fecal dye markers were used to identify appropriate collection times.

RESULTS

Fiber significantly increased the number of bowel movements per day (0.9 +/- 0.4 vs 0.5 +/- 0.2, p < 0.05) and fecal weights (57 +/- 31 vs 32 +/- 25 g/day, p < 0.05). Fiber also caused a significant increase in fecal nitrogen output (110 +/- 65 vs 75 +/- 74 mg/day, p < 0.05) and fecal energy (141 +/- 73 vs 76 +/- 62 kcal/day, p < 0.05). Fiber did not affect fecal moisture, gastric emptying, or intestinal transit time.

CONCLUSION

We conclude that the addition of a combination of soy and oat fiber to tube feeding material is well tolerated, and promotes regular bowel movements without altering the rate of gastric emptying or intestinal transit time.

Intraluminal fungal colonization of gastrostomy tubes

Percutaneous endoscopic gastrostomy tubes are frequently colonized with fungal and bacterial organisms. This has not been previously reported. In our sample of 10 patients, nine percutaneous endoscopic gastrostomy tubes were colonized with fungi. This occurred as early as 1 week after placement. Candida tropicalis was isolated in five patients. It is hypothesized that a variety of fungi use components of the gastrostomy tube polymer, such as polymer additives, which contribute to the structural deterioration of the tube.

Randomised comparison of percutaneous endoscopic gastrostomy and nasogastric tube feeding in patients with persisting neurological dysphagia

OBJECTIVE

To compare percutaneous endoscopic gastrostomy and nasogastric tube feeding in patients with persisting neurological dysphagia.

DESIGN

Randomised 28 day study of inpatients requiring long term enteral nutrition.

SETTING

Three Glasgow teaching hospitals.

SUBJECTS

40 patients with dysphagia for at least four weeks secondary to neurological disorders: 20 patients (10 women) were randomised to nasogastric feeding and 20 (eight women) to endoscopic gastrostomy.

MAIN OUTCOME MEASURES

Treatment failure (blocked or displaced tubes on three or more occasions or refusal to continue treatment); duration of feeding; intake of liquid diets; complications; nutritional status at end of trial.

RESULTS

One patient in each group died before starting feeding. Treatment failure occurred in 18 of the 19 nasogastric patients and in none of the gastrostomy group. The mean (SE) duration of feeding for the nasogastric group was 5.2 (1.5) days. No complications occurred in the nasogastric group but three (16%) of the gastrostomy group developed minor problems (aspiration pneumonia (two patients) wound infection (one)). Gastrostomy patients received a significantly greater proportion of their prescribed feed (93% (2%)) compared with the nasogastric group, (55% (4%); p less than 0.001) and also gained significantly more weight after seven days of feeding (1.4 (0.5) kg v 0.6 (0.1) kg; p less than 0.05). Analyses at days 14, 21, and 28 were not possible due to the small numbers remaining in the nasogastric group.

CONCLUSION

Percutaneous endoscopic gastrostomy tube feeding is a safe and effective method of providing long term enteral nutrition to patients with neurological dysphagia and offers important advantages over nasogastric tube feeding.