Application of refractometry to quality assurance monitoring of parenteral nutrition solutions

Parenteral nutrition (PN) solution contains various concentrations of dextrose, amino acids, lipids, vitamins, electrolytes, and trace elements. Incorrect preparation of PN solution could lead to patient death. In this study we used the refractive index as a quality assurance tool to monitor the preparation of PN solution. Refractive indices of single nutrient components and PN solutions consisting of various concentrations of dextrose, amino acids, electrolytes, and lipids were measured. A mathematical equation and its linear plot were generated then used to predict the refractive index of the PN solution. The best-fit refractive index for PN solution (i.e., the predicted refractive index)=0.9798x(% dextrose)+1.2889x(% amino acids)+1.1017x(% lipids)+0.9440x(% sum of the electrolytes)+0.5367 (r2=0.99). This equation was validated by comparing the measured refractive indices of 500 clinical PN solutions to their predicted refractive indices. We found that 2 of the 500 prepared samples (0.4%) had less than the predicted refractive index (<95%). Refractive index can be used as a reliable quality assurance tool for monitoring PN preparation. Such information can be obtained at the bedside and used to confirm the accuracy of the PN solution composition.

Comparison of the rheological properties of ready-to-serve and powdered instant food-thickened beverages at different temperatures for dysphagic patients

BACKGROUND

Dysphagia, or difficulty swallowing, affects an estimated 15 million Americans. Its management may include use of instant food thickener (IFT) to modify beverage consistency to minimize the risk of aspiration and prevent dehydration. However, inconsistencies with the desired viscosity of these thickened liquids occur both within and across product lines for both ready-to-serve commercially packaged prethickened (CPPT) and IFT-thickened beverages.

OBJECTIVES

To examine the rheological property differences between CPPT and similar IFT-thickened beverages, and to assess the stability of these products at two temperature ranges using three viscosity measurement techniques.

DESIGN

The rheological properties of five CPPT and IFT-thickened beverages at both nectar- and honey-like consistencies were evaluated at 10 degrees C (50 degrees F) and 20 degrees C (68 degrees F) using the line spread, funnel, and viscometry methods.

STATISTICAL ANALYSIS

One-way analysis of variance was used for data analysis. When a significant difference was observed, Tukey's test was used to separate the means.

RESULTS

Each viscosity measurement technique showed the CPPT nectar- and honey-like consistency beverages were significantly more viscous (P<0.0001) at both temperatures compared with their IFT counterparts. Moreover, CPPT beverages at nectar and honey consistencies were almost always more viscous than the National Dysphagia Diet Task Force-defined standards, whereas the IFT-thickened beverages were more frequently within those standards.

CONCLUSIONS

A reevaluation of the viscosity of CPPT beverages with reference to the National Dysphagia Diet Task Force set standard ranges needs to be considered. A strong need also exists for development of a standard protocol on product labels that includes the expected rheological properties of CPPT and IFT-thickened beverages. To the clinicians, especially registered dietitians, it is an important clinical consideration to recognize that CPPT products may be thicker than IFT-thickened products and also may be more viscous than the National Dysphagia Diet Task Force-defined standards.

[Zinc and copper content in individual components used to prepare pediatric total nutrition mixtures]

OBJECTIVES

1) to determine zinc and copper levels of contamination in the individual component solutions used to prepare the pediatric total parenteral nutrition mixtures in Argentina; 2) to compare zinc and copper amounts prescribed by the physician with the true amount given to a neonate weighing 1.2 kg and to a child weighing 10 kg, who would receive total parenteral nutrition formulas prepared with those component solutions.

MATERIALS AND METHODS

Zn and Cu were determined by atomic absorption spectrophotometry in 59 individual solutions belonging to 14 components chosen between the commercial products available in Argentina.

RESULTS

zinc and copper, as contaminants, were found neither in the sterile water, nor in the potassium chloride or in the vitamin solutions. Zinc, but no copper, was detected in sodium chloride, manganese sulfate, chromium chloride and seleniose acid solutions. Zinc and copper were detected in dextrose, amino acids, calcium gluconate and lipid solutions at variable levels. Zinc sulfate solutions contained between 90.4% and 140% of the declared content and a variable contamination with copper. Copper sulfate solutions presented between 4% and 18% less the declared copper concentration and a variable contamination with zinc. Dextrose and lipid solutions presented the highest amount of zinc and copper. Therefore, the total parenteral mixtures prepared with the analyzed solutions must have had an excess of zinc and copper in relation to the prescription: ranging between 103% and 161% and between 7%-426% higher than the Zn and Cu amounts prescribed for neonates, respectively; the excess in the total parenteral nutrition for a child weighing 10 kg would ranged between 105% and 189% and between 7%-365% higher than the prescribed for Zn and Cu, respectively.

CONCLUSIONS

1) Nine components presented Zn and five Cu, both of them not declared in the label; 2) the usually prescribed total parenteral nutrition mixtures must have had a zinc and copper amount higher than the prescribed one according to international recommendations; 3) those figures would be safe in patients without complications, but it would be harmful in renal failure, hepatic compromise or colestasis mainly in pediatric patients; 4) It would be advisable to declare in the label the true content of zinc and copper, with the aim to avoid deficiencies and excess which would compromise the evolution of pediatric patients.

Increasing dietary pectin level reduces utilization of digestible threonine intake, but not lysine intake, for body protein deposition in growing pigs

Two N balance studies were conducted to investigate the effects of feeding graded levels of pectin (a soluble nonstarch polysaccharide, NSP) on the utilization of ileal digestible threonine (Thr; Thr study) and lysine (Lys; Lys study) intake for body protein deposition (PD) in growing pigs. In each study, eight Yorkshire barrows with an average initial BW of 17.2 +/- 1.3 (Thr study) and 14.3 +/- 1.4 kg (Lys study) were fed each of five experimental diets during five subsequent experimental periods, according to a crossover design. Pigs were fed twice daily at 2.6 times maintenance energy requirements. The soybean- and cornstarch-based diets, in which either Thr or Lys was the first-limiting nutrient, were formulated to contain (as-fed basis) 0, 4, 8, or 12% pectin or 8% cellulose (water-insoluble NSP), respectively, and with NSP substituting cornstarch. Across treatments, the mean daily Thr and Lys intake were 5.42 +/- 0.04 g/d (Thr study) and 7.98 +/- 0.12 g/d (Lys study), respectively. Apparent and standardized ileal digestibilities of Thr and Lys were determined in a separate study. Mean PD was 93.4, 90.2, 82.1, 76.7, and 87.9 g/d (SEM = 1.3; Thr study) and 90.7, 88.6, 87.8, 85.3, and 88.1 g/d (SEM = 1.1; Lys study) for the five respective treatments. Utilization of ileal digestible Thr intake, but not of ileal digestible Lys intake, for PD decreased linearly with dietary pectin level, and was not influenced by diet cellulose level. The current study indicates that apparent and standardized ileal digestibility values do not provide an accurate predictor of dietary effects on the utilization of ileal digestible Thr intake for protein deposition in growing pigs fed diets containing soluble NSP.

[Modular parenteral nutrition: a new concept?]

INTRODUCTION

We may define Modular Parenteral Nutrition (MPN) as parenteral nutrition (PN) mixtures obtained from adding different macronutrients to standard formulations (SPN) both binary (amino acids and glucose) and ternary (amino acids, lipids, and glucose).

OBJECTIVES

The aim of this study is to demonstrate that PN formulations may be adapted to individual needs of each patient and workload may be reduced by using MPN.

MATERIAL AND METHODS

Case-control retrospective study of PN prepared during the first semester of the years 1995, 2000, and 2005. PN are categorized in: standard (SPN) -given without manipulation-, individualized (IPN), and modular parenteral nutrition (MPN). The protocols are compared at the different periods, and the volume of transferred fluid is related with total prepared volume in order to calculate the workload. The Chi squared and student's t tests with a significance level of p < 0.05 are used.

RESULTS

In 1995, virtually only individualized formulations were used. In the year 2000, SPN and MPN were introduced as maintenance formulas as well as those for moderate stress. Finally, in the year 2005, the modular concept has been introduced for severe stress and/or immunomodulatory formulas. As a result of these changes, we observe in the protocol a decrease in IPN due to progressive introduction of MPN. In 1995, MPN represented 2.6% of all elaborations, increasing up to 64.7% in 2000, and to 74.7% in 2005. This fact has resulted in a decrease in transferred volume through the volumetric elaboration system. In 1995, 87.3% of the total volume was transferred, in the year 2000 34.3%, and finally in 2005 only 20.6% (the differences between the three periods are statistically significant; p < 0.05). In the year 2005, 543 IPN were elaborated, of which 169 (31.1%) were for patients with liver encephalopathy or non-dialyzed acute renal failure. The following ingredients have been added to MPN during that same period: glutamine, fish oil lipid emulsions lipidicas, structured lipids, olive-pattern lipids, polyionic solutions, and specific micronutrients.

DISCUSSION

MPN allows for adapting PN formulas to a wide range of clinical situations, although individualized formulations still are irreplaceable for some pathologies. The use of MPN is associated with a decrease in individualized formulas that reflects in lower workload.

Impact of nutrient density of nocturnal enteral feeds on appetite: a prospective, randomised crossover study

OBJECTIVE

To determine whether the energy density of isocaloric nocturnal enteral feeds (NEF) influences daily nutrient intake in children.

METHOD

In a 6 week, randomised, crossover trial, the impact on spontaneous nutrient intake of manipulating the energy density of two isocaloric overnight feeds (1.0 kcal/ml and 1.5 kcal/ml) was compared in a group of 32 children aged 1-10 years (or 8-25 kg body weight) on long term, overnight enteral feeding at home. Total daily oral energy, protein, fat and carbohydrate intake were assessed using 3 day food diaries. Anthropometric data were also recorded during the study.

RESULTS

Spontaneous intakes of energy, protein, fat and carbohydrate from food were 20-30% greater when receiving the lower nutrient density feed (1 kcal/ml). This was due to a gender effect; males consumed twice as much protein from food than females and had slightly higher (but not significant) energy and fat intakes when on the larger volume feed. All children increased in weight, height and mid-upper arm circumference in the 6 week period.

CONCLUSIONS

Children appear to tolerate and grow equally well, irrespective of the nutrient density and volume of NEF taken. However, it appears that children will consume a more energy and nutrient dense oral diet when given their NEF as a higher volume/lower nutrient density feed. This is particularly so for boys, while for girls the volume of NEF or feed concentration appeared to have no impact on quantity of oral diet taken. However, further blinded studies with larger subject numbers would be useful to support these findings.

Determinación de los índices glicémicos y de insulina en fórmulas para alimentación enteral en adultos sanos

BACKGROUND

In acute illnesses, plasma glucose levels are often increased and generally parallel the severity of stress. Hyperglycemia caused by reduced insulin sensitivity and reduced insulin secretion is associated with increased susceptibility to infections. Maintaining blood glucose levels at or below 110 mg/dl reduces morbidity and mortality in critically ill patients.

AIM

To measure the glucose and insulin responses of four commercially available enteral formulas compared with a standard meal reference product.

MATERIAL AND METHODS

The glycemic index (GI) and the insulin index (II) were determined in a randomized, cross over protocol in 38 healthy volunteers between 18 and 46 years of age. Each subject underwent five tests: three with the standard meal (bread) and two with the study products. The enteral formulas were Clinutren HPR (whole protein of high protein value), Crucial (casein peptide based formula), Peptamen, (whey peptide based formula), Glytrol (formula for diabetics with whole protein with fiber). Each study product was evaluated 10 times.

RESULTS

The diabetic formula and the high protein energy dense formulas induced a significantly lower GI (p <0.02) compared with the standard meal. The GI response did not appear to be due to enhanced insulin secretion. The other tested formulas had lower GI than the standard meal, but in addition they exhibited increased II The whey based peptide formulation produced the highest insulin response (p <0.03).

CONCLUSIONS

Both GI and II are related to the concentration, form and type of protein contained in the enteral formula. The whey peptide formulation produced a low GI with the highest insulin index. Based on the low GI of these enteral products, all can be useful to provide nutritional support during metabolic stress, without adding an additional challenge to blood glucose management.

Nutritional immunomodulation of acute pancreatitis

Despite the great advances in our understanding of the pathophysiology of acute pancreatitis, no specific therapy has emerged, and treatment remains supportive. In patients with the severe form of the disease, in which mortality remains high at 20% to 30%, the function of the upper gastrointestinal tract is disturbed due to extrinsic compression by the inflamed and swollen pancreas, and normal eating is impossible. Such patients often develop multiple organ failure, necessitating intensive-care management and artificial ventilation for weeks on end. In this setting, protein catabolism will rapidly result in protein deficiency and further complications unless nutritional support is commenced. Recent studies have shown that, despite the risk of disease exacerbation through pancreatic stimulation, enteral feeding is more effective than parenteral feeding in improving outcome. Experimental studies suggest that this can be attributed to its content of specific immunomodulating nutrients, such as glutamine, arginine, and n-3 fatty acids, and by its stabilizing effect on the gut flora through the provision of prebiotics. Further studies are indicated to examine whether dietary enrichment with these substrates, along with regulation of the gut bacteria with probiotics, can improve outcome further.

Nutritional modulation of protein metabolism after gastrointestinal surgery

BACKGROUND

The metabolic response to surgery includes alterations in protein metabolism, resulting in a net loss of proteins. Protein hypercatabolism is considered an unavoidable consequence of injury, and an important source of morbidity and mortality. Our purpose was to determine the effect of nutrition on protein metabolism following gastrointestinal surgery, and to elucidate whether postoperative protein loss can be prevented with adequate nutritional support.

METHODS

Patients who had undergone gastrointestinal surgery were given four different parenteral nutritions with increasing glucose, lipid and amino acid content during the 7 days following surgery. Nitrogen balance, protein synthesis and protein breakdown were determined using in vivo stable isotope labelling. Other metabolites (3-methylhistidine, creatinine, urea, cortisol, glucose, insulin, amino acids and C-reactive protein) were measured.

RESULTS

A nutrition-dependent alteration of protein metabolism was found in response to surgical injury. Nutrition modified nitrogen balance, whole-body protein breakdown and, to a lesser extent, whole-body protein synthesis and muscle protein breakdown. The low-energy parenteral nutrition without amino acids produced a negative nitrogen balance (postoperative day 7=-0.381 g protein kg(-1)day(-1)) and important alterations in postoperative protein metabolism that did not normalize during the study period (day 7 protein synthesis=239% and protein breakdown 217% vs preoperative). Patients receiving the two low energy parenteral nutritions containing amino acids had a less negative nitrogen balance (day 7=-0.011 and -0.133 g protein kg(-1)day(-1)) and a transient increase in protein metabolism. The complete parenteral nutrition maintained, during all studied days, protein metabolism parameters within the preoperative reference range (synthesis day 2=92%, day 4=110% day 7=79%; breakdown day 2=85%, day 4=80%, day 7=76% vs preoperative) and a positive nitrogen balance (day 2=+0.0387, day 4=+0.578 and day 7=+0.227 g protein kg(-1)day(-1)).

CONCLUSION

Complete nutritional support can prevent protein loss after gastrointestinal surgery and maintain protein metabolism without alterations.

Enteral nutritional therapy for induction of remission in Crohn's disease

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This meta-analysis aims to provide an update on the existing effectiveness data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the effectiveness of exclusive enteral nutrition (EN) as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on effectiveness.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2006) and EMBASE (1984-2006), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: American Journal of Gastroenterology, Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two authors and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstract publications, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 15 included eligible trials (one abstract) comparing different formulations of EN for the treatment of active CD, 11 compared one (or more) elemental formula to a non-elemental one, three compared enteral diets of similar protein composition but different fat composition, and one compared non-elemental diets differing only in glutamine enrichment. Meta-analysis of ten trials comprising 334 patients demonstrated no difference in the efficacy of elemental versus non-elemental formulas (OR 1.10; 95% CI 0.69 to 1.75). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no statistically significant differences. Further analysis of seven trials including 209 patients treated with EN formulas of differing fat content (low fat: < 20 g/1000 kCal versus high fat: > 20 g/1000 kCal) demonstrated no statistically significant difference in efficacy (OR 1.13; 95% CI 0.63 to 2.01). Similarly, the effect of very low fat content (< 3 g/1000 kCal) or type of fat (long chain triglycerides) were investigated, but did not demonstrate a difference in efficacy in the treatment of active CD, although a non significant trend was demonstrated favoring very low fat and very low long chain triglyceride content. This result should be interpreted with caution due to statistically significant heterogeneity and small sample size. Sensitivity analyses had no significant effects on the results. The role of specific fatty acids or disease characteristics on response to therapy could not be evaluated. In part B, eight trials (including two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of six trials that included 192 patients treated with enteral nutrition and 160 treated with steroids yielded a pooled OR of 0.33 favouring steroid therapy (95% CI 0.21 to 0.53). A sensitivity analysis including the abstracts resulted in an increase in the number of participants to 212 in the enteral nutrition group and 179 in the steroid group but the meta-analysis yielded a similar result (OR 0.36; 95% CI 0.23 to 0.56). There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

AUTHORS' CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in previous systematic reviews. Protein composition does not influence the effectiveness of EN in the treatment of active CD. A non significant trend favouring very low fat and/or very low long chain triglyceride content exists but larger trials are required to explore the significance of this finding.

[Effects of resistant starch RS4 on magnesium and iron absorption in Wistar rats]

The effect of resistant starch RS4 on apparent absorption of magnesium and iron was studied in Wistar rats. The rats (4 groups male n=12 and 4 groups female n=12) were fed for 4 weeks diets: control with wheat starch (K) and 3 diets with modified resistant starches (S1, S2, S3). After an adaptation period (14 d), rats were transferred to metabolic cages. Dietary intake and faeces were monitored for 3 days. Mg and Fe levels were assessed in diets and feces by atomic absorption spectrometry. Apparent absorption of minerals was calculated as mineral intake minus fecal excretion and expressed as persentage of intake. Our results confirmed that Mg apparent absorption in female rats fed diet with resistant starch S2 was significantly increased (+37%) compared with the control group.

Appetite during consumption of enteral formula as a sole source of nutrition: the effect of supplementing pea-fibre and fructo-oligosaccharides

Liquid enteral formulas are commonly used as a sole source of nutritional support of patients in hospital and community settings. Their effect on appetite has important consequences for dietary management of such patients and is likely to be affected by the formula composition. The aim of the present study was to compare appetite within healthy subjects consuming both a standard formula and one supplemented with pea-fibre (10 g/l) and fructo-oligosaccharide (FOS; 5 g/l) as a sole source of nutrition. Eleven healthy subjects consumed a standard formula or a pea-fibre/FOS formula as a sole source of nutrition for 14 d in a double-blind, cross-over trial. Appetite was recorded using standard 100 mm lines anchored at each end by a phrase denoting the most extreme appetite sensation. Consumption of the pea-fibre/FOS formula resulted in higher mean fullness (46 v. 37 mm, P=0.035), minimum fullness (13 v. 9 mm, P=0.024) and minimum satiety (12 v. 8 mm, P=0.012) compared to the standard formula. As there were no differences in macronutrient intake between formulas, these differences are likely to be due to supplementation with pea-fibre and FOS. The effect on appetite of the composition of an enteral formula, both with respect to nutrient content and functional components such as pea-fibre and FOS, may be an important aspect to consider in the dietary management of patients consuming enteral formula as a sole source of nutrition.

Semi-elemental formula or polymeric formula: is there a better choice for enteral nutrition in acute pancreatitis? Randomized comparative study

BACKGROUND

Jejunal nutrition is recommended during acute pancreatitis. The use of semi-elemental formulas presents several theoretical advantages over polymeric formulas, but their clinical value has been poorly documented. Our aim was to evaluate in patients with acute pancreatitis the effect of enteral nutrition by a semi-elemental formula compared with a polymeric formula.

METHODS

A randomized prospective pilot study, stratified according to severity, was performed in 30 consecutive patients with acute pancreatitis requiring jejunal nutrition. The semi-elemental group received 35 kcal/kg/d of Peptamen (n = 15), and the polymeric group received the same quantity of Sondalis-Iso (n = 15). Tolerance was evaluated after 7 days of enteral nutrition (D7) on visual analog scale (VAS), stool frequency, and 24-hour steatorrhea/creatorrhea. Outcome was evaluated by weight loss, length of hospital stay, and infection rate.

RESULTS

Results were calculated as mean +/- SEM, t-test, or chi2. Patients of the 2 groups were comparable in terms of age, gender, and severity. Tolerance was good in both groups (semi-elemental vs polymeric: VAS, 7.4 +/- 0.6 vs 7.1 +/- 0.6, not significant (NS); number of stools per 24 hours, 1.7 +/- 0.4 vs 1.8 +/- 0.4, NS). Steatorrhea and creatorrhea were lower than normal in both groups. In semi-elemental group, the length of hospital stay was shorter (23 +/- 2 vs 27 +/- 1, p = .006) and weight loss was less marked (1 +/- 1 vs 2 +/- 0, p = .01). One patient in semi-elemental group and 3 patients in polymeric group developed an infection (NS).

CONCLUSIONS

Semi-elemental and polymeric nutrition are very well tolerated in patients with acute pancreatitis. Nutrition with a semi-elemental formula supports the hypothesis of a more favorable clinical course than nutrition with a polymeric formula, but this conclusion needs to be established in larger adequately powered clinical trials.

A rapid and simple procedure for the determination of synephrine in dietary supplements by gas chromatography-mass spectrometry

A simple and rapid procedure based on gas chromatography-mass spectrometry (GC-MS) is described for determination of synephrine, active principle of Citrus aurantium plant, in solid and liquid dietary supplements. After the addition of 3,4-methylenedioxypropylamphetamine as internal standard (I.S.), a liquid-liquid extraction procedure in alkaline conditions with chloroform/isopropanol (9:1, v/v) was applied to the samples prior to analysis. Chromatography was performed on a fused capillary column and synephrine and I.S., derivatized with pentafluoropropionic anhydride, were determined in the selected-ion-monitoring (SIM) mode. The method was validated in the range 0.1-50 microg/mg or microg/mL synephrine. Mean recovery ranged between 89.3% and 90.5% in both solid and liquid dietary supplements. The quantification limit was 0.1 microg/mg or microg/ml. The method was applied to analysis of various dietary supplements promoted for aiding weight control containing, among other constituents such as ephedrine alkaloids and methylxanthines, Citrus aurantium. Amount of synephrine present in such products ranged from 3.1 microg/mg solid product to 480.2 microg/mL liquid product.

Measurements of gastric emptying during continuous nasogastric infusion of liquid feed: electric impedance tomography versus gamma scintigraphy

BACKGROUND & AIMS

Continuous nasogastric infusion is commonly used to deliver enteral feed but current methods used to assess tolerance based on aspiration and measurement of gastric residual volume have been criticised. Electric impedance tomography (EIT) measures gastric emptying by monitoring changes in epigastric impedance when a meal progressively empties from the stomach.

AIMS

(1) to establish whether EIT was a valid method for measuring gastric emptying during continuous nasogastric infusion by comparing it with gamma scintigraphy (GS) and (2) to provide data on gastric emptying patterns during continuous nasogastric infusion.

METHODS

Gastric emptying of 400 ml of enteral feed given over 200 min was measured simultaneously using EIT and GS in 10 healthy volunteers (five male and five female).

RESULTS

Gastric emptying curves were obtained in 10 subjects by EIT but only eight by GS. Visual examination of the curves showed reasonable agreement. Patterns of emptying and filling during continuous nasogastric infusion were variable between individuals; the prevailing pattern was a trend towards a steady-state volume of approximately 50-125 ml.

CONCLUSIONS

While EIT does not provide an accurate estimate of gastric volume during continuous infusion, it does show patterns of gastric emptying over time. With further development this could make it a useful tool for monitoring gastric emptying in patients at risk of gastroparesis.

Essential mixed cryoglobulinemia type II

We report a rare case of essential mixed cryoglobulinemia type II with membrano-proliferative glomerulonephritis (MPGN) type I in which HCV was not found. Long-term history of palindromic rheumatism, skin leukocytoclastic vasculitis attacks and micro-normocytic anemia preceded the appearance of cryoglobulinemia. Cryoprecipitate consisted of monoclonal IgMk-RF and polyclonal IgG (essential mixed type II). The newly appreciated cryoglobulinemia was associated with Coombs positive hemolytic anemia. The MPGN in this case had a benign course and responded to complex simple therapies including prevention of exposure to cold, low antigen content diet, treatment of provoking factors such as UTI, and maximal dose of ACE inhibitor. Responsiveness of skin vasculitis to colchicine therapy was restored after a two-month colchicine withdrawal period and therefore corticosteroid and immunosuppressive therapy was postponed.

Rapid detection of the addition of soybean proteins to cheese and other dairy products by reversed-phase perfusion chromatography

The undeclared addition of soybean proteins to milk products is forbidden and a method is needed for food control and enforcement. This paper reports the development of a chromatographic method for routine analysis enabling the detection of the addition of soybean proteins to dairy products. A perfusion chromatography column and a linear binary gradient of acetonitrile-water-0.1% (v/v) trifluoroacetic acid at a temperature of 60 degrees C were used. A very simple sample treatment consisting of mixing the sample with a suitable solvent (Milli-Q water or bicarbonate buffer (pH=11)) and centrifuging was used. The method enabled the separation of soybean proteins from milk proteins in less than 4 min (at a flow-rate of 3 ml/min). The method has been successfully applied to the detection of soybean proteins in milk, cheese, yogurt, and enteral formula. The correct quantitation of these vegetable proteins has also been possible in milk adulterated at origin with known sources of soybean proteins. The application of the method to samples adulterated at origin also leads to interesting conclusions as to the effect of the processing conditions used for the preparation of each dairy product on the determination of soybean proteins.

Validation the use of refractometer and mathematic equations to measure dietary formula contents for clinical application

BACKGROUND AND AIMS

Gastric residual volumes are widely used to evaluate gastric emptying for patients receiving enteral feeding, but controversy exists about what constitutes gastric residual volume. We have developed a method by using refractometer and derived mathematical equations to calculate the formula concentration, total residual volume (TRV), and formula volume. In this study, we like to validate these mathematical equations before they can be implemented for clinical patient care.

METHODS

Four dietary formulas were evaluated in two consecutive validation experiments. Firstly, dietary formula volume of 50, 100, 200, and 400 ml were diluted with 50 ml water, and then the Brix value (BV) was measured by the refractometer. Secondly, 50 ml of water, then 100 ml of dietary formula were infused into a beaker, and followed by the BV measurement. After this, 50 ml of water was infused and followed by the second BV measurement. The entire procedure of infusing of dietary formula (100 ml) and waster (50 ml) was repeated twice and followed by the BV measurement.

RESULTS

The formula contents (formula concentration, TRV, and formula volume) were calculated by mathematical equations. The calculated formula concentrations, TRVs, and formula volumes measured from mathematic equations were strongly close to the true values in the first and second validation experiments (R2>0.98, P<0.001).

CONCLUSIONS

Refractometer and the derived mathematical equations may be used to accurately measure the formula concentration, TRV, and formula volume and served as a tool to monitor gastric emptying for patients receiving enteral feeding.

Treatment of active Crohn's disease in children using partial enteral nutrition with liquid formula: a randomised controlled trial

BACKGROUND AND AIMS

Total enteral nutrition (TEN) with a liquid formula can suppress gut inflammation and induce remission in active Crohn's disease. The mechanism is obscure. Studies have suggested that long term nutritional supplementation with a liquid formula (partial enteral nutrition (PEN)) may also suppress inflammation and prevent relapse. The aim of this study was to compare PEN with conventional TEN in active Crohn's disease.

PATIENTS AND METHODS

Fifty children with a paediatric Crohn's disease activity index (PCDAI)>20 were randomly assigned to receive 50% (PEN) or 100% (TEN) of their energy requirement as elemental formula for six weeks. The PEN group was encouraged to eat an unrestricted diet while those receiving TEN were not allowed to eat. The primary outcome was achievement of remission (PCDAI<10). Secondary analyses of changes in erythrocyte sedimentation rate (ESR), C reactive protein, albumin, and platelets were performed to look for evidence of anti-inflammatory effects.

RESULTS

Remission rate with PEN was lower than with TEN (15% v 42%; p=0.035). Although PCDAI fell in both groups (p=0.001 for both), the reduction was greater with TEN (p=0.005). Moreover, the fall in PCDAI with PEN was due to symptomatic and nutritional benefits. With both treatments there were significant improvements in relation to abdominal pain, "sense of wellbeing", and nutritional status. However, only TEN led to a reduction in diarrhoea (p=0.02), an increase in haemoglobin and albumin, and a fall in platelets and ESR.

CONCLUSIONS

TEN suppresses inflammation in active Crohn's disease but PEN does not. This suggests that long term nutritional supplementation, although beneficial to some patients, is unlikely to suppress inflammation and so prevent disease relapse.

Effects of multiple pulmonary aspirations of enteral solutions on lung tissue damage

BACKGROUND & AIM

The aim of this study was to compare the pulmonary histopathologic effects of enteral solutions with various lipid content, after multiple aspirations in rats.

METHODS

Thirty Wistar albino rats were randomly assigned to one of three groups (n = 10). Saline solution (0.9%) (group C, control), Impact (lipid content, 28 g/l; group I), Pulmocare (lipid content, 93.3g/l; group P) were injected into the lung through the trachea, in a volume of 0.8 ml/kg. The aspiration procedure was performed three times in total, in every 2 days. After seven days from the first aspiration, rats were killed, and lungs were examined for histopathologic examination.

RESULTS

Alveolar histiocytes were statistically higher in left lungs of the group I than the left ones of the control group (P < 0.05). Lipid-laden alveolar macrophages were significantly higher in left lungs of groups I and, P than left lungs of the control group (P<0.05).

CONCLUSION

Lung tissue damage occurring after multiple pulmonary aspirations of Impact and Pulmocare, is histopathologically similar to each other, and is in the form of lipoid pneumonia. In cases of multiple pulmonary aspirations, volume of the aspirate and chronicity of the aspiration look like major impact factors rather than the amount of the lipid.

A chronic dietary toxicity study of DAG (diacylglycerol) in Beagle dogs

The potential chronic toxic effects of DAG (diacylglycerol) when administered orally for 12 months were evaluated in this dietary study in Beagle dogs. DAG is a cooking oil which contains >80% diglycerides, <20% triglycerides and 5% monoglycerides. For this study, a special diet was prepared with no dietary fat so that all of the dietary fat could be provided by DAG, at various concentrations together with a control oil. The control oil, TG (triacylglycerol), was prepared to contain >85% triglycerides, <10% diglycerides and 5% monoglycerides. The fatty acid composition for DAG and TG was closely matched. Dietary concentrations of 0% DAG/9.5% TG (TG control), 1.5% DAG/8.0% TG, 5.5% DAG/4.0% TG, and 9.5% DAG/0% TG were presented daily, seven days per week, for 52 weeks. A second concurrent control group received the standard basal diet (Certified Canine LabDiet 5007, which has a fat content of 9.5%). The basal diet, control article-treated and DAG-treated groups each consisted of four male and four female dogs. Treatment was initiated in prejuvenile (2.5-month-old) dogs. Statistical evaluations compared the DAG-treated groups both to the basal diet and 9.5% TG control groups. The clinical condition of the animals, body weights, body weight gains and food consumption were unaffected by DAG. Hematology and urinalysis parameters were unaffected. No serum chemistry changes indicative of a toxic effect were observed. There were no effects noted on ECG data. No test article-related gross or histopathologic findings or changes in organ weights were observed. While there were no identifiable differences between the effects of TG and DAG, both caused some differences relative to the basal diet (lower food consumption, higher alkaline phosphatase, cholesterol and triglycerides). These differences were not toxicologically significant and were attributed to the differences in the diet rather than the fat source. Thus, DAG at dietary concentrations up to 9.5% for one year had no effect on normal canine growth and development, in comparison to TG.

The Glycemic Index of standard and diabetes-specific enteral formulas

A recent meta-analysis showed that foods with a low Glycemic Index (GI) have a clinically useful effect on glycemic control in patients with diabetes. Although diabetes-specific enteral formulas are commonly used for diabetic patients with insufficient oral intake, not much is known about the GI of these formulas. Therefore the purpose of this study was to assess the GI of several diabetes-specific formulas and to compare them with standard formulas. The randomised, double blinded, crossover study included twelve products which were tested in 7-10 individuals from a pool of 14 healthy volunteers. After an overnight fast, volunteers were given a portion of a product containing 25 grams of carbohydrate or the reference feed (200 ml containing 25 gram glucose) on different occasions in random order. Postprandial blood glucose levels were measured in venous whole blood for two hours after intake of the products and positive incremental area under the curve (AUC) was calculated for both the products and the reference feed. The GI of the test products was determined by dividing AUC (test products) by the AUC (reference feed). Enteral formulas varied widely in their GI values with the diabetes-specific enteral formulas being characterized by a significant (P=0.004) lower GI (average +/-SEM: 19.4 +/- 1.8) than standard formulas (42.1 +/- 5.9). However, there was an overlap between the two types of formulas. Three of the diabetes-specific formulas had significantly lower GI than 3 of the standard products. Although there is some overlap with the GI of diabetes-specific and standard formulas, certain diabetes-specific formulas had very low GI values, which may be clinically beneficial due to better glycemic control. Therefore the use of diabetes-specific formulas with a low GI should be the preferred option for the nutritional management of diabetic patients in need of nutritional support.