Prolonged nasogastric tube feeding in critically ill and surgical patients

Intermittent versus continuous enteral nutrition attenuates increases in insulin and leptin during short-term bed rest

PURPOSE

To compare endocrine responses to intermittent vs continuous enteral nutrition provision during short-term bed rest.

METHODS

Twenty healthy men underwent 7 days of bed rest, during which they were randomized to receive enteral nutrition (47%E as carbohydrate, 34%E as fat, 16%E as protein and 3%E as fibre) in a continuous (CONTINUOUS; n = 10; 24 h day-1 at a constant rate) or intermittent (INTERMITTENT; n = 10; as 4 meals per day separated by 5 h) pattern. Daily plasma samples were taken every morning to assess metabolite/hormone concentrations.

RESULTS

During bed rest, plasma leptin concentrations were elevated to a lesser extent with INTERMITTENT vs CONTINUOUS (iAUC: 0.42 ± 0.38 vs 0.95 ± 0.48 nmol L-1, respectively; P = 0.014) as were insulin concentrations (interaction effect, P < 0.001) which reached a peak of 369 ± 225 pmol L-1 in CONTINUOUS, compared to 94 ± 38 pmol L-1 in INTERMITTENT (P = 0.001). Changes in glucose infusion rate were positively correlated with changes in fasting plasma GLP-1 concentrations (r = 0.44, P = 0.049).

CONCLUSION

Intermittent enteral nutrition attenuates the progressive rise in plasma leptin and insulinemia seen with continuous feeding during bed rest, suggesting that continuous feeding increases insulin requirements to maintain euglycemia. This raises the possibility that hepatic insulin sensitivity is impaired to a greater extent with continuous versus intermittent feeding during bed rest. To attenuate endocrine and metabolic changes with enteral feeding, an intermittent feeding strategy may, therefore, be preferable to continuous provision of nutrition. This trial was registered on clinicaltrials.gov as NCT02521025.

Clinical applications of amylase: Novel perspectives

BACKGROUND

Amylase was the first enzyme to be characterized, and for the previous 200 years, its clinical role has been restricted to a diagnostic aid. Recent interface research has led to a substantial expansion of its role into novel, viable diagnostic, and therapeutic applications to cancer, infection, and wound healing. This review provides a concise "state-of-the-art" overview of the genetics, structure, distribution, and localization of amylase in humans.

METHOD

A first-generation literature search was performed with the MeSH search string "Amylase AND (diagnost∗ OR therapeut$)" on OVIDSP and PUBMED platforms. A second-generation search was then performed by forward and backward referencing on Web of Knowledge™ and manual indexing, limited to the English Language.

RESULTS

"State of the Art" in amylase genetics, structure, function distribution, localisation and detection of amylase in humans is provided. To the 4 classic patterns of hyperamylasemia (pancreatic, salivary, macroamylasemia, and combinations) a fifth, the localized targeting of amylase to specific foci of infection, is proposed.

CONCLUSIONS

The implications are directed at novel therapeutic and diagnostic clinical applications of amylase such as the novel therapeutic drug classes capable of targeted delivery and "smart release" in areas of clinical need. Future directions of research in areas of high clinical benefit are reported.

Alterations in fluid, electrolytes and other serum chemistry values and their relations with enteral tube feeding in acute brain infarction patients

AIMS AND OBJECTIVES

This study was performed to examine whether fluid and electrolyte levels are significantly altered after enteral tube feeding in acute brain infarction patients.

BACKGROUND

Results on the water and electrolyte complications associated with enteral tube feeding are inconsistent and this is partly because of uncontrolled disease-related variables.

DESIGN

Non-experimental design (retrospective study).

METHODS

This study was conducted by retrospectively reviewing the medical records of 85 tube-fed patients.

RESULTS

Mean values of major serum electrolytes (sodium, potassium and chloride) were not significantly altered by tube feeding. However, differences between fluid input and output were significantly increased after tube feeding. The incidence of dehydration reduced overall, while over-hydration increased.

CONCLUSION

The enteral tube feeding of iso-osmolar formulae appeared to be tolerated by most subjects in the present study in terms of electrolyte balance. However, fluid imbalance and over-hydration incidences were significantly increased after tube feeding.

RELEVANCE TO CLINICAL PRACTICE

Due to significant alterations in fluid balance after tube feeding, close attention to the recording of fluid balance, such as intake/output measurements, body weights and simple bedside assessments is needed to detect fluid imbalances and other serious complications at an early stage in enteral tube-feeding patients.

Effects of Nasogastric Tube Feeding on Serum Sodium, Potassium, and Glucose Levels

PURPOSE

To examine whether significant alterations in serum sodium, potassium, and glucose levels occurred after nasogastric tube feeding with iso-osmolar formula in acute brain infarction patients.

DESIGN AND METHODS

Serum sodium, potassium, and glucose levels were analyzed by a retrospective medical record review of 85 nasogastric tube-fed patients.

FINDINGS

The mean values of serum sodium and potassium levels on the day before, and 1st, 2nd, and 3rd days of nasogastric feeding were within the normal range. Alterations in the incidence rates of high, normal, and low level of serum sodium and potassium after tube feeding were not statistically significant. The mean blood glucose levels on the day before, and 1st, 2nd, and 3rd days of tube feeding were above normal, and the increase after tube feading was not statistically significant.

CONCLUSIONS

Enteral tube feeding using iso-osmolar formula did not significantly alter serum sodium and potassium balance. However, most participants were hyperglycemic before and after tube feeding, indicating that hyperglycemia can be induced in the acute stages of brain infarction regardless of tube feeding.

Therapeutic drug monitoring of theophylline in frail elderly patients: oral compared with nasogastric tube administration

SUMMARY

Treating debilitated elderly patients through nasogastric tube (NGT) can change the pharmacokinetic characteristics of drugs, mainly those that are slow released (SR). The purpose of this study was to compare pharmacokinetic parameters between patients who receive SR theophylline orally and those who receive it through NGT.

PATIENTS AND METHODS

The authors studied elderly patients in the geriatric ward receiving SR theophylline for chronic obstructive lung disease. In 17 patients fed by NGT (group I), theophylline was removed from the capsule and mixed with 10 mL of water. Group II included 15 patients who swallowed the drug orally. Theophylline blood levels were measured, as were peak concentration (C(max) ), time to peak (T(max) ), and area under the serum concentration-time curves (AUC).

RESULTS

The mean daily dose was not statistically different between the two groups: 320 +/- 130 (200-500) mg/d in group I and 360 +/- 85 (200-500) mg/d in group II, given twice daily. All pharmacokinetic measurements were lower in group I as compared with group II: trough theophylline blood levels were 3.78 +/- 3.2 (0.5-10.77) microg/mL versus 8.63 +/- 4.6 (0-15.61) microg/mL ( P= 0.002); C(max) was 6.53 +/- 4.1 (1.3-13.33) microg/mL versus 10.51 +/- 3.30 (4.3-16.28) microg/mL (P = 0.0058), and AUC was 50.04 +/- 38.59 (11-112) microg/h/mL versus 80.37 +/- 28.8 (23-148) microg/h/ml (P = 0.024). CONCLUSIONS Patients receiving the drug through NGT had variability and unexpectedly low blood levels. Therefore, the pharmacokinetic parameters of SR preparations should be evaluated before their administration through NGT.

Enteral feeding. Nasogastric, nasojejunal, percutaneous endoscopic gastrostomy, or jejunostomy: its indications and limitations

The following article is intended to provide a review of the current state of enteral feeding; a rapidly changing and developing field. It covers the type of feed, the routes of access, and the problems that can occur with enteral feeding.

GI complications in patients receiving mechanical ventilation

Mechanical ventilation (MV) can be lifesaving by maintaining gas exchange until the underlying disorders are corrected, but it is associated with numerous organ-system complications, which can significantly affect the outcome of critically ill patients. Like other organ systems, GI complications may be directly attributable to MV, but most are a reflection of the severity of the underlying disease that required intensive care. The interactions of the underlying critical illness and MV with the GI tract are complex and can manifest in a variety of clinical pictures. Incorporated in this review are discussions of the most prevalent GI complications associated with MV, and current diagnosis and management of these problems.

Protein and carbohydrate absorptive efficiency of chronically malnourished and well-nourished patients during enteral feeding initiation

To investigate the efficiency of protein and carbohydrate absorption, we studied malnourished and well-nourished subjects during the first 72 hours of tube feeding. We furthermore investigated whether differences in absorptive efficiency existed between malnourished patients with and without nongastrointestinal malignancy. Twenty-one subjects starting tube feeding without edema or major organ failure and not on antibiotics (well-nourished controls = 7; malnourished = 7; malnourished with nongastrointestinal malignancy = 7) received 50 kcal/hr Osmolite continuously for 72 hours. Twelve of these subjects completed an additional 48 hours of study where they received 125 kcal/hr continuously. We performed hydrogen breath tests to assess carbohydrate absorption and determined stool nitrogen content to assess protein absorption. We also measured frequency of defecation, stool weight, and stool moisture content. The results of these tests failed to reveal statistically significant differences between the three groups in terms of protein and carbohydrate absorption, as well as failed to demonstrate the presence of diarrhea. We conclude that patients receiving an isoosmolar diet who are malnourished, or malnourished with nongastrointestinal malignancy, absorb carbohydrate and protein as well as well-nourished patients during enteral hyperalimentation.

Diarrhea complicating enteral feeding after liver transplantation

In this case report we present in detail the complex nature of enteral feeding, diarrhea, hypoalbuminemia, and edema in a critically ill patient. We also discuss the use of a peptide-elemental formula in this patient, who suffered continuous diarrhea for 15 weeks after liver transplantation. Use of this formula was associated with cessation of the diarrhea and permitted adequate nutritional delivery. After 26 weeks of mechanical pulmonary ventilation, extubation was possible. This case illustrates the ineffectiveness of parenteral albumin infusions for treatment of enteral edema and demonstrates the restoration of normal intestinal absorptive capacity when ultrafiltration was instituted and the patient's generalized edematous state was corrected.

Indications for tube feedings in elderly patients

Tube feedings are utilized in elderly patients with acute and chronic problems. Inadequate oral intake with malnutrition, comatose state, neurologic disorders with severe dysphagia, extensive burns, massive gastrointestinal resection, and oropharyngeal and upper gastrointestinal malignancies are the commonly encountered conditions requiring tube alimentation. Dysphagia with frequent aspiration is the most common indication for use of tube feedings in the elderly. Nasogastric tube is preferred for short-term feeding, while gastrostomy or jejunostomy is indicated for long-term or permanent nutritional support. Nutritional assessment should be done initially and on a regular basis. Specific formulas are available to calculate height, weight, and caloric needs of bedbound elderly patients. Various enteral feeding formulas are available for a specific clinical condition and are preferably administered by continuous drip using a pump. Parenteral nutrition is also indicated for certain situations in which enteral feeding cannot meet the patient's nutritional requirement, and in particular situations where enteral feeding is contraindicated and not feasible. Optimal patient care is dependent on adequate nutritional support.

Soy-polysaccharide fiber: effect on diarrhea in tube-fed, head-injured patients

In a randomized, double-blind, crossover study the effect of tube-feeding with soy-polysaccharide fiber (SPF) vs without SPF on stool weight (SW), stool consistency (SC), fecal nitrogen (FN), and incidence of diarrhea (ID) was compared in nine head-injured subjects; associations with feeding volume, albumin level, and medications were also examined. Subjects with and without SPF had (mean +/- SEM) SW of 245 +/- 47 and 277 +/- 49 g/d, SC of 2.17 +/- 0.01 and 2.52 +/- 0.13 (3 is watery) (p less than 0.01), FN of 1.35 +/- 0.45 and 1.36 +/- 0.33 g/d, and ID of 33% and 44%, respectively. Significant treatment X treatment-sequence interaction nullified results for SW and SC. Neither FN nor ID were affected by SPF. The condition of all variables tended to improve over time. Certain medications and SPF were predictive of SW and SC; albumin and tube-feeding volume were not. SPF-containing tube feedings did not seem to have an effect on bowel function in these well-nourished head-injured patients.

Effect of a fecal bulking agent on diarrhea during enteral feeding in the critically ill

Diarrhea is a common complication of enteral feeding in critically ill patients. This placebo-controlled clinical trial assessed the effect of adding fiber in the form of 'Fybogel' (Ispaghula husk), one sachet twice daily, on the occurrence of diarrhea during enteral feeding. Sixty-eight patients without prospectively defined exclusion criteria were enterally fed with 'Osmolite' in the Intensive Care Unit during the study period, 35 receiving 'Fybogel', and 33 placebo. Nineteen patients in each group had diarrhea on at least 1 day during enteral feeding, with 66 (23%) feeding days complicated by diarrhea in the 'Fybogel' group, and 68 (23%) in the placebo group. Narcotic infusions, thiopentone infusions, 'Mylanta', H2-antagonists, and nystatin suspension did not significantly affect the incidence of diarrhea. Weak correlations were found between diarrhea and the number of antibiotics each patient received (r = 0.2, p less than 0.05) and also the number of positive nonenteral bacterial cultures (r = 0.2, p less than 0.05). The addition of fiber in the form of 'Fybogel' to enteral feeds did not affect the occurrence of diarrhea.

Diarrhea in tube-fed burn patients: incidence, etiology, nutritional impact, and prevention

The hypermetabolic state observed in thermally injured patients warrants aggressive nutritional management. Enteral support is the preferred route of nutrient delivery, however diarrhea is reported to be a persistent complication of continuous nasogastric or nasoduodenal hyperalimentation. Diarrhea adds to problems in patient care, disturbs fluid and electrolyte balance, and worsens nutritional status. There has been the impression that tube feeding hyperosmolality, antibiotics, and low serum albumin induce diarrhea. However, in view of the sparsity of published work, a prospective study was undertaken to determine the incidence of diarrhea and to define factors associated with its cause. Of the 50 patients studied, 16 (32%) developed diarrhea. Stool cultures were negative for pathogenic organisms. Although the risk of diarrhea was associated with antibiotics (p less than 0.005), several nutrients also had an impact. Results demonstrated a significant relationship between dietary lipid content (p less than 0.05) or vitamin A intake (p less than 0.001) and diarrhea. Implementation of tube feeding within 48 hrs postburn was also associated with a decreased incidence of diarrhea (p less than 0.001). This paper describes a modular tube feeding program in which diarrheal frequency is lessened (p less than 0.0001). Surprisingly, tube feeding osmolality, drugs used to prevent stress ulcers, or hypoalbuminemia did not have an adverse effect on intestinal absorption. The cause of diarrhea in burn patients is obviously multifactorial. It is concluded that a low fat (less than 20% of caloric intake), vitamin A enriched (greater than 10,000 IU/day), early enteral support program maximizes conditions which promote tube feeding tolerance while minimizing nutrient malabsorption during the nutritional rehabilitation of thermal injury.

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.

Complications of enteral nutrition

Complications may arise during enteral feeding that are usually related to the diameter and rigidity of the tube or the delivery, composition, and sterility of the feed uses. By using a soft, fine bore tube to deliver a sterile feed of known composition, by continuous infusion rather than as a bolus, most of these complications can be avoided.

Overnight nasogastric tube feeding

Overnight nasogastric tube feeding allows the patient freedom for normal daytime activities and exercise, essential components of rehabilitation. In order to avoid disturbed nights through frequent micturition we have kept the volume of feed to a minimum. Two types of feed have been used: 1. A supplementary isosmolar feed containing 1000 kCals in 1 litre. 2. A concentrated low volume (404 mosm/kg) feed supplying 1800 kCals including 60 g of nitrogen in 1 litre. Both were delivered via a fine bore tube (internal diameter 1 mm) by continuous infusion from a 1-1.5 litre reservoir using a rotary pump. Feed 1 was given to 64 undernourished elderly female patients (group 1) with fractured neck of femur, the tube being tolerated by 78%; 47 patients in this group were fed for more than 5 days. Feed 2 was given to 10 patients in hospital (group 2) and 8 patients at home (group 3). Few side effects were encountered, the hyperosmolar feed causing no diarrhoea, nausea or hyperglycaemia, emphasising the importance of osmoles per unit time rather than per unit volume. Voluntary oral intake was neither impaired nor increased during the period of tube feeding in group 1, in whom anorexia and thinness were longstanding. In group 2, with recent onset of anorexia and weight loss, tube feeding disinhibited appetite, resulting in a doubling of voluntary oral intake. Improvement in anthropometric and biochemical nutritional parameters was seen in all patients. Clinical improvements e.g. closure of fistulae were also observed. This paper describes the results of our trial of both these options in patients treated in hospital or at home.

The effect of different carbohydrate intakes on body weight and nitrogen balance during nasogastric feeding after faciomaxillary surgery

In order to assess the effects on body composition of different carbohydrate intakes when nitrogen supply is constant and adequate (9 g/day), we gave either no carbohydrate, sufficient to avoid ketosis (100 g) or at least enough to satisfy energy needs (600 g) to a group of six patients after major faciomaxillary surgery. Each patient was given the different feeds for 3-day periods in a randomised, cross over design. 100 g carbohydrate was effective in avoiding negative nitrogen balance, but weight loss was only prevented when 600 g was used. Differences in water balance suggest that mobilisation and repletion of body glycogen (with associated water) probably account for most of these differences in body weight changes.

Benefits of supplementary tube feeding after fractured neck of femur: a randomised controlled trial

A total of 744 elderly women with fractured neck of femur were classified into three groups according to anthropometric measurements on admission: group 1, well nourished; group 2, thin; group 3, very thin. Group 1 ate well and had a low mortality and a short rehabilitation time. The thinner the patients the lower their voluntary food intake, the higher their mortality and the longer their rehabilitation time. A series of 122 patients from groups 2 and 3 were entered postoperatively into a randomised controlled trial of overnight supplementary nasogastric tube feeding (4.2 MJ (1000 kcal), including 28 g protein) in addition to their normal ward diet. This treatment was associated with improvements not only in anthropometric and plasma protein measurements but also in clinical outcome, especially in the very thin group 3 patients. Rehabilitation time and hospital stay were shortened. Mortality in group 3 was less in the tube fed patients (8%) than in the controls (22%) but this difference did not reach statistical significance. One in five patients could not tolerate the nasogastric tube, but in the remainder the treatment caused no side effects and did not seriously diminish voluntary oral food intake by day.

Complications occurring during enteral nutrition support: a prospective study

A review of 253 patients treated with enteral nutrition support via tube feedings is presented for the purpose of evaluating the incidence of complications. Thirty patients, (11.7%) experienced either gastrointestinal, (6.2%) mechanical (3.5%), or metabolic (2.0%) complications. The recognition and treatment of such complications are discussed and it is concluded that tube feedings are safely tolerated by most patients; however, constant attention must be exerted to either avoid or recognize such complications.

A primate model for enteral nutrition by tube

To establish an animal model for the controlled study of enteral nutrition by tube, five adult chair-adapted primates (Macaca fasicularis) had gastrostomy and jejunostomy tubes placed for the delivery of a modified protein isolate diet. Following 7 days of postoperative depletion with a hypocaloric infusion of dextrose (20 kcal, 0 g N/kg/day), the animals were repleted for 10 days with tube feedings (124 kcal, 0.73 g N/kg/day). There was no operative mortality or morbidity and each animal demonstrated conversion to anabolism by significant weight gain, positive nitrogen balance, and net protein synthesis as determined by [15N]glycine protein turnover rates. Significant correlation was found between caloric intake and nitrogen balance at the level of nitrogen provided in this diet (r = 0.88, p less than 0.05). This model was found to be well suited for the surgical and nutritional techniques required for the long-term study of enteral nutrition by tube.

Indications for pump-assisted enteral feeding

Of 80 patients fed enterally over nine months, 10 had serious gastrointestinal complications from gravity-controlled continuous enteral feeding. Use of an infusion pump controlled diarrhoea in patients with gastrointestinal disorders, but was less successful in patients with poor gastric emptying or impaired swallowing reflexes. Thus a pump is not indicated for routine use but, in carefully selected patients, it can obviate the necessity for parenteral nutrition.