Enteral nutrition: should we feed the stomach?

Nutrition Support in Adult Trauma Patients

Nutrition supplementation is paramount to the care of severely injured patients. Despite its widespread use in trauma patients, many areas of clinical practice remain controversial. The purpose of this paper is to critically review the literature studying the use of enteral vs parenteral nutrition (PN) and to provide the rationale for early enteral nutrition. Additional controversies confronting clinicians are reviewed, including the use of immune-enhancing agents and the optimal site for enteral nutrition delivery (gastric vs small intestinal). Evidence-based recommendations for clinical practice are presented when available.

Variation in enteral nutrition delivery in mechanically ventilated patients

OBJECTIVE

We determined the variability in enteral feeding practices in mechanically ventilated patients in four adult intensive care units of a tertiary-care, referral hospital.

METHODS

Patients who had been mechanically ventilated for at least 48 h and received enteral nutrition were prospectively followed.

RESULTS

Fifty-five of 101 consecutive mechanically ventilated patients received enteral nutrition; in 93% of patients, feedings were infused into the stomach. Patients who were cared for in the medical intensive care unit, where a nutritional protocol was operational, received enteral nutrition earlier in their ventilatory course (P=0.004) and feedings were advanced to target rates faster (P=0.043) than those who received care in other units. The number (P=0.243) and duration (P=0.668) of interruptions in feeding did not differ by patient location. On average, patients received only 50% to 70% of their targeted caloric goals during the first 6 days of enteral nutrition. Most feeding discontinuations (41%) were secondary to procedures. Gastrointestinal intolerances, including vomiting, aspiration, abdominal distention, and increased gastric residuals, were uncommon despite allowing gastric residuals up to 300 mL.

CONCLUSIONS

The practice of providing enteral feeds to mechanically ventilated patients varies widely, even within one hospital. A protocol enhanced early initiation of enteral feeds and advancement to target feeding rates but did not alter the number or duration of interruptions in enteral feedings. Procedures represented the most common reason for stopping enteral feeds, and gastrointestinal intolerances (vomiting, aspiration, and increased gastric residuals) caused few feeding interruptions. The gastric route was safe and well tolerated for early enteral feeding in most mechanically ventilated patients.

Effect of gastrointestinal motility and feeding tube site on aspiration risk in critically ill patients: a review

OBJECTIVE

The purpose of this literature review is to examine the effect of the interaction between gastrointestinal motility and feeding site on the aspiration risk in critically ill, tube-fed patients.

METHODS AND RESULTS

A single answer to the question of the preferred feeding site is not likely to be found because the degree of aspiration risk varies significantly according to individual variations in gastrointestinal motility and multiple pre-existing and treatment-related risk factors. However, regardless of the feeding site, it is ultimately regurgitated gastric contents that are aspirated into the lungs. For this reason, the clinical assessment of greatest interest is the evaluation of gastric emptying, usually monitored clinically by measuring gastric residual volumes.

CONCLUSION

Current recommendations for monitoring residual volumes and preventing aspiration are provided.

Gastric versus post-pyloric feeding: a systematic review

BACKGROUND

Our objective was to evaluate the impact of gastric versus post-pyloric feeding on the incidence of pneumonia, caloric intake, intensive care unit (ICU) length of stay (LOS), and mortality in critically ill and injured ICU patients.

METHOD

Data sources were Medline, Embase, Healthstar, citation review of relevant primary and review articles, personal files, and contact with expert informants. From 122 articles screened, nine were identified as prospective randomized controlled trials (including a total of 522 patients) that compared gastric with post-pyloric feeding, and were included for data extraction. Descriptive and outcomes data were extracted from the papers by the two reviewers independently. Main outcome measures were the incidence of nosocomial pneumonia, average caloric goal achieved, average daily caloric intake, time to the initiation of tube feeds, time to goal, ICU LOS, and mortality. The meta-analysis was performed using the random effects model.

RESULTS

Only medical, neurosurgical and trauma patents were enrolled in the studies analyzed. There were no significant differences in the incidence of pneumonia, percentage of caloric goal achieved, mean total caloric intake, ICU LOS, or mortality between gastric and post-pyloric feeding groups. The time to initiation of enteral nutrition was significantly less in those patients randomized to gastric feeding. However, time to reach caloric goal did not differ between groups.

CONCLUSION

In this meta-analysis we were unable to demonstrate a clinical benefit from post-pyloric versus gastric tube feeding in a mixed group of critically ill patients, including medical, neurosurgical, and trauma ICU patients. The incidences of pneumonia, ICU LOS, and mortality were similar between groups. Because of the delay in achieving post-pyloric intubation, gastric feeding was initiated significantly sooner than was post-pyloric feeding. The present study, while providing the best current evidence regarding routes of enteral nutrition, is limited by the small total sample size.

Nutritional support in the critically ill child

The nutritional management of a critically ill child is not a glamorous subject and seldom receives the attention that it merits despite increasing evidence that appropriate goal-oriented nutritional support is associated with improved outcome. Current nutritional management is based on rapidly emerging knowledge on the very special nutritional requirements related to the "vastly different metabolic and physiologic characteristics of the hypermetabolic and stressed" critically ill child. There has been significant changes in traditional practice particularly in the area of calorie delivery, amount of macronutrients and route of nutrient delivery in the critically ill child. The critically ill child presents with "greatly disordered nutrient metabolism" and successful nutritional support involves an initial "hypocaloric regime" with a precise mix of carbohydrates, proteins and lipids which need periodic review as the child improves. The therapeutic benefits of minimal enteral feeding (MEF) have been clearly established--MEF being associated with diminished morbidity, infection rates as well as reduced ICU and hospital stays. Immune enhancement has also been shown to be of some benefit in the critically ill but the subject needs further study.

Postinjury enteral tolerance is reliably achieved by a standardized protocol

BACKGROUND

Postinjury enteral nutrition (EN) is beneficial. Unfortunately, severely injured patients who should benefit most are frequently intolerant. To assist in maximizing enteral tolerance in the critically injured, we first implemented a prospective analysis of the effectiveness of a standardized enteral protocol (EP) at a single institution followed by a prospective multi-institutional analysis of its implementation.

METHODS

Tolerance parameters were prospectively collected on severely injured patients at a single (Phase I) and then multiple (Phase II) institutions. EN was begun at 15 cc/h and advanced every 12 h to a patient specific targeted goal. Intolerance symptoms (high nasogastric output/emesis, abdominal distention, and diarrhea) were assessed and graded every 12 h and managed using a standardized protocol. Tolerance was characterized as early (during initial advancement of feeds) or late (after standard goal) and classified as good (EN advanced per EP), moderate (rate decreased per EP), poor (EN held per EP), or EN discontinued (and TPN begun).

RESULTS

In Phase I patients (ISS = 25 +/- 3) early tolerance was good in 82% (14/17) while late good tolerance decreased to 65% (11/17). In Phase II patients (ISS = 30 +/- 2), early tolerance was good in 85% (41/49) and late tolerance was good in 80% (39/49). Moderate intolerance was primarily seen in Phase II patients and due to high gastric output in patients fed proximal to the ligament of Treitz (13/16). Overall 88% (15/17) of Phase I and 100% (49/49) of Phase II patients were successfully maintained on EN.

CONCLUSIONS

Severely injured patients exhibited good tolerance to EN when managed using a standardized protocol at four Level I trauma centers. Moderate intolerance was associated with high gastric output and may be lessened by feeding distal to the ligament of Treitz.

Multicenter, prospective, randomized, single-blind study comparing the efficacy and gastrointestinal complications of early jejunal feeding with early gastric feeding in critically ill patients

OBJECTIVE

To compare the incidence of enteral nutrition-related gastrointestinal complications, the efficacy of diet administration, and the incidence of nosocomial pneumonia in patients fed in the stomach or in the jejunum.

DESIGN

Prospective, randomized multicenter study.

SETTING

Intensive care units (ICUs) in 11 teaching hospitals.

PATIENTS

Critically ill patients who could receive early enteral nutrition more than 5 days.

INTERVENTIONS

Enteral nutrition was started in the first 36 hrs after admission. One group was fed with a nasogastric tube (GEN group) and the other in the jejunum through a dual-lumen nasogastrojejunal tube (JEN group).

MEASUREMENTS AND MAIN RESULTS

Gastrointestinal complications were previously defined. The efficacy of diet administration was calculated using the volume ratio (expressed as the ratio between administered and prescribed volumes). Nosocomial pneumonia was defined according the Centers for Disease Control and Prevention's definitions. One hundred ten patients were included (GEN: 51, JEN: 50). Both groups were comparable in age, gender, Acute Physiology and Chronic Health Evaluation II, and Multiple Organ Dysfunction Score. There were no differences in feeding duration, ICU length of stay, or mortality (43% vs. 38%). The JEN group had lesser gastrointestinal complications (57% vs. 24%, p <.001), mainly because of a lesser incidence of increased gastric residuals (49% vs. 2%, p <.001). Volume ratio was similar in both groups. A post hoc analysis showed that the JEN group had a higher volume ratio at day 7 than the GEN group (68% vs. 82%, p <.03) in patients from ICUs with previous experience in jejunal feeding. Both groups had a similar incidence of nosocomial pneumonia (40% vs. 32%).

CONCLUSIONS

Gastrointestinal complications are less frequent in ICU patients fed in the jejunum. Nevertheless, it seems to be a necessary learning curve to achieve better results with a postpyloric access. Early enteral nutrition using a nasojejunal route seems not to be an efficacious measure to decrease nosocomial pneumonia in critically ill patients.

Endoscopically Placed Nasogastrojejunal Feeding Tubes: A Safe Route for Enteral Nutrition in Patients with Hepatic Encephalopathy

Patients with hepatic encephalopathy are at particular risk for aspiration when given oral or gastric feedings. An ideal strategy might combine distal enteral feeding with proximal gastric decompression, which is offered by a nasogastrojejunal (NGJ) feeding tube. One objective was to determine the efficacy and safety of endoscopically placed NGJ feeding tubes in patients with hepatic encephalopathy. Charts of patients who underwent NGJ tube placements between April 1997 and January 2000 were retrospectively reviewed. Two endoscopic techniques (“push” and “pull”) were used. Eighteen patients (nine male and nine female) underwent 32 procedures. Twelve patients had undergone liver transplantation, four had decompensated cirrhosis, and two had fulminant hepatic failure. Twenty procedures used the push technique and 12 required the pull technique. The insertion time was shorter for the push technique compared with the pull technique (21.8 vs 39.6 min, P < 0.05). Enteral feedings were begun at an average of 5.2 hours after tube placement. The tubes remained in place for an average of 13.9 days. Complications related to the NGJ tubes included self-removal in eight, tube clogging in five, proximal migration in four, and intraduodenal migration of the gastric port in one. No aspiration episodes occurred. We conclude that NGJ feeding tubes may be placed endoscopically as a bedside procedure for patients with hepatic encephalopathy and provide a safe, efficacious, and rapid route for enteral nutrition in these patients.

Migrating motility complexes persist after severe traumatic shock in patients who tolerate enteral nutrition

BACKGROUND

Postinjury small bowel ileus is poorly characterized and may be an important factor in intolerance to enteral nutrition (EN). We, therefore, placed jejunal manometry catheters in high-risk trauma patients. Our hypothesis was that the presence of "fasting migrating motility complex (MMC)" activity and conversion to a "fed pattern" at goal rate of EN would be present in those patients who tolerate jejunal feeding.

METHODS

After obtaining baseline fasting manometry pressure tracings, jejunal feeding was advanced stepwise to a set goal while tolerance was monitored and intolerance was treated by a standard approach.

RESULTS

Of the 10 study patients, 7 were able to be maintained on EN. Five (50%) had "fasting MMCs" and had good tolerance to early advancement of EN. The remaining five patients did not exhibit "fasting MMCs" and four had poor tolerance to early advancement of EN. Overall, nine patients reached goal rate of EN of which four converted to a "fed pattern." This, however, was not associated with later tolerance to EN.

CONCLUSION

EN is feasible following severe traumatic shock. Surprisingly, half of the patients had fasting MMCs. This requires intact neural and motor function and was associated with good tolerance of early EN.

Effectiveness and safety of a protocol for promotion of early intragastric feeding in critically ill children

OBJECTIVES: To investigate the feasibility, adequacy, and efficacy of early poststress intragastric feeding (EPIGF) in critically ill children. DESIGN: A prospective clinical study. SETTING: Pediatric intensive care unit in a tertiary care children's hospital. PATIENTS: Seventy-one consecutively enrolled critically ill children requiring prolonged mechanical ventilation. INTERVENTIONS: Full-strength intragastric tube feedings (Nutrison Pediatric, Standard) were initiated within 12 hrs of the study-entry event. Enteral feedings were advanced to a target volume of energy intake = 1/2, 1, 5/4, 6/4, and 6/4 of the predicted basal metabolic rate (PBMR) on days 1-5, respectively. MEASUREMENTS AND MAIN RESULTS: Nutritional status by the caloric intake, recommended dietary allowances, PBMR, predicted energy expenditure (PEE), anthropometry, and clinical indices were evaluated on days 1 and 5. Safety was assessed by the clinical course of disease, laboratory findings, and occurrence of complications. Success was determined by accomplishment of the PEE target. The early success rate was 94.4% and predicted late enteral feeding success accurately (p =.0001). Caloric intake approached PBMR the second day (43 +/- 1.7 kcal/kg/day vs. 43.2 +/- 1.1 kcal/kg/day) and PEE the fifth day (66.2 +/- 2.7 kcal/kg/day vs. 67.7 +/- 6.4 kcal/kg/day). Multivariate stepwise regression analysis showed that poor outcome and a high Therapeutic Intervention Scoring System score correlated with failure of EPIGF (p <.0001). Patients who succeeded EPIGF had significantly higher myocardial ejection (65% vs. 43%; p <.0001) or shortening fractions (34% vs. 20%; p =.0001) on day 1 than those who failed. Patients tolerated EPIGF well; 9.9% developed nosocomial pneumonia, 5.6% developed diarrhea, and 8.5% needed treatment with cisapride because of a delay of gastric emptying. The mortality rate (5.6%) was different between initial and final success and failure groups (p <.0001) and was lower than predicted by the admission severity scores (12% +/- 2%). CONCLUSIONS: This study showed that increases of caloric intake during the acute phase of a critical illness are well tolerated and may approach PBMR by the second day and PEE by the fourth day in critically ill children. Caloric intake lower than PBMR is associated with higher mortality and morbidity rates.