Monitoring bolus nasogastric tube feeding by the Brix value determination and residual volume measurement of gastric contents

BACKGROUND: Critically ill patients do not always tolerate nasogastric tube feeding. Gastric residual volumes (GRVs), obtained by aspiration from a nasogastric tube, are widely used to evaluate feeding tolerance and gastric emptying, but controversy exists about what constitutes the true GRV (diet formula or digestive juice) and how it should affect management. In this pilot study, we used the Brix value (BV) measurement of gastric contents to monitor both GRV and food content in patients receiving nasogastric feeding. METHODS: Forty-three patients receiving bolus nasogastric feeding were monitored for 24 hours before entry into the study and then divided into 2 groups according to traditional use of GRV; patients with low GRVs (< 75 mL) were placed in group 1, whereas patients with higher GRVs (> 75 mL) were placed in group 2. All subjects were given 250 mL of polymeric formula by bolus nasogastric infusion, followed by BV measurement of gastric contents at 0, 30, 60, 120, and 180 minutes. All gastric fluid was aspirated after 180 minutes of feeding; the volume was recorded and BV measurement made, then reinstilled with an added 30 mL of dilutional water, after which a final aspiration and BV measurement was performed. Calculated GRV and volume of formula remaining in the stomach was determined by derived equations. RESULTS: Serial BV measurements decreased in both groups after bolus feeding. For patients in group 2, the decrease was less such that at 180 minutes, the mean BV for gastric contents was significantly higher than for those patients in group 1 (10.1 vs 5.1, respectively; p < .01). Aspirated GRV, calculated GRV, and volume of formula remaining in the stomach at 180 minutes were significantly greater for patients in group 2 compared with those in group 1. Use of refractometry in combination with traditional use of GRV identified 4% (1/25) of patients in group 1 with low GRVs who might have possible gastric dysmotility (> 20% of initial 250-mL volume of formula remaining at 180 minutes) and ensured that 72% (13/18) of patients in group 2 with higher GRVs had sufficient gastric emptying (< 20% of initial 250 mL volume of formula remaining). CONCLUSION: This pilot study raises the feasibility that refractometry and the BV measurement of gastric juice may be a promising tool for bedside monitoring of tolerance and gastric emptying in patients receiving nasogastric feeding, providing valuable complementary information to traditional use of GRV.     

Gastric residual volume (GRV) and gastric contents measurement by refractometry

BACKGROUND: Traditional use of gastric residual volumes (GRVs), obtained by aspiration from a nasogastric tube, is inaccurate and cannot differentiate components of the gastric contents (gastric secretion vs delivered formula). The use of refractometry and 3 mathematical equations has been proposed as a method to calculate the formula concentration, GRV, and formula volume. In this paper, we have validated these mathematical equations so that they can be implemented in clinical practice. METHODS: Each of 16 patients receiving a nasogastric tube had 50 mL of water followed by 100 mL of dietary formula (Osmolite HN, Abbott Laboratories, Columbus, OH) infused into the stomach. After mixing, gastric content was aspirated for the first Brix value (BV) measurement by refractometry. Then, 50 mL of water was infused into the stomach and a second BV was measured. The procedure of infusion of dietary formula (100 mL) and then water (50 mL) was repeated and followed by subsequent BV measurement. The same procedure was performed in an in vitro experiment. Formula concentration, GRV, and formula volume were calculated from the derived mathematical equations. RESULTS: The formula concentrations, GRVs, and formula volumes calculated by using refractometry and the mathematical equations were close to the true values obtained from both in vivo and in vitro validation experiments. CONCLUSIONS: Using this method, measurement of the BV of gastric contents is simple, reproducible, and inexpensive. Refractometry and the derived mathematical equations may be used to measure formula concentration, GRV, and formula volume, and also to serve as a tool for monitoring the gastric contents of patients receiving nasogastric feeding.     

Effect of feeding-tube properties on residual volume measurements in tube-fed patients

BACKGROUND: The effect of feeding tube size and port configuration on the ability to measure gastric residual volume (GRV) is poorly understood. In addition, there is confusion about the need to measure GRVs during feedings into the small bowel. This study sought to (1) compare the volume of gastric contents obtained from small-diameter feeding tubes and large-diameter sump tubes concurrently positioned in the stomach and (2) describe the distribution of GRVs during small-bowel feedings. METHODS: For the first objective, GRV measurements were made from 10-Fr tubes (n = 645) and 14-Fr or 18-Fr sump tubes (n = 645) concurrently present in 62 critically ill patients. Sixty-milliliter syringes were used to measure GRVs from the 10-Fr tubes; the fluid was returned to the stomach and measurements were repeated from the large-diameter sump tubes. To address the second research objective, 890 GRV measurements were made from 14-Fr or 18-Fr gastric sump tubes (not connected to suction) in 75 critically ill patients who were receiving small-bowel feedings. RESULTS: When GRVs were >50 mL, a linear regression equation indicated that volumes obtained from the large-diameter sump tubes were about 1.5 times greater than those obtained from the small-diameter tubes concurrently present in the stomach, p < .001. Gastric volumes > or =100 mL were found in 11.6% of the 890 measurements made in patients receiving small-bowel feedings; volumes > or =150 mL were found in 5.4% of the measurements. CONCLUSIONS: The findings suggest that GRVs obtained from large-diameter sump tubes are about 1.5 times greater than those obtained from 10-Fr tubes. Large GRVs occur in at least 5% of patients receiving postpyloric feedings.     

Enhancing interpretation of gastric residual volume by refractometry.

The traditional practice of gastric residual volumes (GRVs) is flawed in its design and conception, is poorly standardized in its technique, is an inaccurate measure of gastric emptying, and serves as an insensitive marker for regurgitation and aspiration. The refractive index of a solution (like an enteral formula) is a physical property of that solution, which is remarkably constant and reproducible under varying conditions of concentration, pH, and temperature. Refractometry may be performed quickly and easily at the bedside, requires only a small representative sample of aspirated solution, and provides valuable measurements that can be used to calculate both the true total volume of contents and the specific volume of formula remaining in the stomach. Refractometry complements the use of GRVs as a monitor for patients receiving enteral feeding and should improve the accuracy with which patients at risk for aspiration may be identified.     

The paracetamol absorption test: a useful addition to the enteral nutrition algorithm?

BACKGROUND: Enteral nutrition in critically ill patients given via the nasogastric route is often decreased or stopped because of large gastric residual volumes. AIM: To assess the effect of continuing enteral nutrition in patients with an elevated gastric residual volume but normal gastric emptying by the paracetamol absorption test. METHODS: The paracetamol absorption test was performed on all patients receiving enteral nutrition via a nasogastric tube who had a residual volume (assessed every 8 hours) of >150 ml or more than twice the hourly infusion rate. Patients were then divided into 2 groups according to the result of the test: Group 1 (n=8), normal gastric emptying; and Group II (n=24), abnormal gastric emptying. Group I continued to receive enteral nutrition. In Group II feeding was interrupted in 18 patients and prokinetic agents administered, while a subgroup of six patients continued to receive enteral nutrition without prokinetic agents. All patients were followed for evidence of delayed gastric emptying and aspiration. RESULTS: Residual volumes were similarly elevated in both groups (p=0.25). Enteral nutrition was continued in Group I with no adverse effects. Prokinetic agents allowed enteral nutrition to be resumed in 88% of the 18 Group II patients. Enteral nutrition in the subgroup had to be stopped because of persistently elevated residual volumes. CONCLUSION: The paracetamol absorption test may be normal in patients with relatively high gastric residual volumes. These patients may continue to receive enteral nutrition.     

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.     

Gastric Emptying in Critically Ill Children

Background: Delayed gastric emptying (GE) impedes enteral nutrient (EN) delivery in critically ill children. We examined the correlation between (a) bedside EN intolerance assessments, including gastric residual volume (GRV); (b) delayed GE; and (c) delayed EN advancement. Materials and Methods: We prospectively enrolled patients ≥1 year of age, eligible for gastric EN and without contraindications to acetaminophen. Gastric emptying was determined by the acetaminophen absorption test, specifically the area under the curve at 60 minutes (AUC₆₀). Slow EN advancement was defined as delivery of <50% of the prescribed EN 48 hours after study initiation. EN intolerance assessments (GRV, abdominal distension, emesis, loose stools, abdominal discomfort) were recorded. Results: We enrolled 20 patients, median 11 years (4.4–15.5), 50% male. Sixteen (80%) patients had delayed GE (AUC₆₀ <600 mcg·min/mL) and 7 (35%) had slow EN advancement. Median GRV (mL/kg) for patients with delayed vs normal GE was 0.43 (0.113–2.188) vs 0.89 (0.06–1.91), P = .9635. Patients with slow vs rapid EN advancement had median GRV (mL/kg) of 1.02 mL/kg (0.20–3.20) vs 0.27 mL/kg (0.06–1.62), P = .3114, and frequency of altered EN intolerance assessments of 3/7 (42.9%) vs 5/13 (38.5%), P = 1. Median AUC₆₀ for patients with slow vs rapid EN advancement was 91.74 mcg·min/mL (53.52–143.1) vs 449.5 mcg·min/mL (173.2–786.5), P = .0012. Conclusions: A majority of our study cohort had delayed GE. Bedside EN intolerance assessments, particularly GRV, did not predict delayed GE or rate of EN advancement. Delayed gastric emptying predicted slow EN advancement. Novel tests for delayed GE and EN intolerance are needed.     

Oropharyngeal Dysphagia and Impaired Motility of the Upper Gastrointestinal Tract—Is There a Clinical Link in Neurocritical Care?

Patients in the neurological ICU are at risk of suffering from disorders of the upper gastrointestinal tract. Oropharyngeal dysphagia (OD) can be caused by the underlying neurological disease and/or ICU treatment itself. The latter was also identified as a risk factor for gastrointestinal dysmotility. However, its association with OD and the impact of the neurological condition is unclear. Here, we investigated a possible link between OD and gastric residual volume (GRV) in patients in the neurological ICU. In this retrospective single-center study, patients with an episode of mechanical ventilation (MV) admitted to the neurological ICU due to an acute neurological disease or acute deterioration of a chronic neurological condition from 2011–2017 were included. The patients were submitted to an endoscopic swallowing evaluation within 72 h of the completion of MV. Their GRV was assessed daily. Patients with ≥1 d of GRV ≥500 mL were compared to all the other patients. Regression analysis was performed to identify the predictors of GRV ≥500 mL/d. With respect to GRV, the groups were compared depending on their FEES scores (0–3). A total of 976 patients were included in this study. A total of 35% demonstrated a GRV of ≥500 mL/d at least once. The significant predictors of relevant GRV were age, male gender, infratentorial or hemorrhagic stroke, prolonged MV and poor swallowing function. The patients with the poorest swallowing function presented a GRV of ≥500 mL/d significantly more often than the patients who scored the best. Conclusions: Our findings indicate an association between dysphagia severity and delayed gastric emptying in critically ill neurologic patients. This may partly be due to lesions in the swallowing and gastric network.     

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.     

莫沙必利和多潘立酮对卧床鼻饲的急性脑卒中患者肺部感染的影响

目的 观察莫沙必利和多潘立酮对卧床、鼻饲的急性脑卒中患者医院内肺部感染发生率的影响.方法 89例卧床、鼻饲的急性脑卒中患者,采用随机数字表法分为研究组(47例)和对照组(42例),两组均给予脑卒中常规治疗,研究组在此基础上服用莫沙必利5 mg,多潘立酮20 mg,每日3次,连续4周.观察住院4周内两组患者肺部感染发生率及鼻饲后3 h胃内容物残留例次及残留量,并进行统计学分析.结果 住院4周内,研究组肺部感染13例,对照组25例,发生率分别为27.66%(13/47)和59.52%(25/42),两组比较差异有统计学意义(P<0.01).鼻饲后3 h鼻胃管中可抽出食物的患者共26l例次,其中对照组237例次,残留量(112.17±32.54)ml;研究组24例次,残留量(50.80±15.38)ml,两组患者鼻饲后3 h有胃内容物残留的例次及残留量比较差异均有统计学意义(P<0.01).结论 对于卧床、鼻饲的急性脑卒中患者,在常规治疗基础上服用莫沙必利和多潘立酮,可显著降低患者医院内肺部感染发生率.     

Gastric motility function in critically ill patients tolerant vs intolerant to gastric nutrition

BACKGROUND: Administration of gastric enteral nutrition (EN) in the intensive care unit (ICU) is commonly impeded by high gastric residual volumes (GRV). This study evaluated gastric emptying in patients with limited GRV (tolerant group) vs volumes > or =150 mL (intolerant group) and whether prokinetic therapy improves gastric motility in intolerant patients. METHODS: To assess gastric motility, mechanically ventilated patients received acetaminophen 975 mg, and peak plasma concentration (Cmax), concentration at 60 minutes (C(60)), time to Cmax (Tmax), and area under the concentration-time curve from 0 to 60 minutes (AUC(0-60)) were determined. This evaluation was repeated in intolerant patients after 24 hours of either erythromycin 250 mg or metoclopramide 10 mg therapy, both administered intravenously every 6 hours. RESULTS: Ten tolerant and 20 intolerant patients were studied. Tolerant patients had significantly greater Cmax (14.12 +/- 7.25 vs 9.28 +/- 5.22 mg/L; p < .05), C(60) (9.62 +/- 4.65 vs 6.08 +/- 4.00 mg/L; p < .001), and AUC(0-60) (10.01 +/- 5.97 vs 3.93 +/- 2.84 mg/h/L; p < .01) and shortened Tmax (0.81 +/- 0.61 vs 1.98 +/- 1.26 hours; p < .001) compared with intolerant patients. After prokinetic therapy, Cmax (15.26 +/- 8.85 mg/L), C(60) (11.96 +/- 5.99 mg/L), and AUC(0-60) (10.90 +/- 6.57 mg/h/L) increased and Tmax (1.07 +/- 1.01 hours) decreased in the intolerant group to values similar to the tolerant group. CONCLUSIONS: ICU patients with elevated GRV during gastric EN have delayed gastric motility. Initiating prokinetic therapy accelerates gastric emptying to resemble that of ICU patients tolerating EN.     

ICU病人胃残留量临界值设置的研究进展

监测胃残留量(GRV)是ICU护士对行肠内营养(EN)病人进行安全管理的一项常规操作,但GRV临界值的设置一直缺乏统一标准。近年来,多项临床研究表明,提高GRV临界值并不影响EN的安全性。以下就GRV监测的影响因素、提高GRV临界值的可行性与必要性以及部分国家对GRV监测新的管理意见作一综述。     

Gastric emptying of two whey-based formulas of different energy density and its clinical implication in children with volume intolerance

OBJECTIVE: Whey-based formulas have faster gastric emptying than casein-based formulas. Isoenergetic, isovolumic, whey-based formulas of different osmolarity and fat content empty in a similar manner. Will the gastric emptying of high and low energy density whey-based formulas be similar? DESIGN: We studied the gastric emptying rate of equal volumes of two whey-based formulas of different energy density (4.18 kJ/ml and 6.27 kJ/ml) and osmolality (270 and 450 mOsm/kg, respectively) in 10 children (4.5-12 y) with volume intolerance and resultant inability to gain weight. RESULTS: The two formulas had comparable gastric emptying rates at 30, 60, 90 and 120 min. Over a one month clinical trial, substitution of the lower energy density whey-based formula (no weight gain over 2 months) with an equal volume of the high energy density formula produced a mean weight gain of 1.17+/-0.5 kg per patient without change in tolerance. CONCLUSION: The higher density whey-based formula can safely substitute an equal volume of a lower energy density formula to produce weight gain without affecting tolerance. IMPLICATION: This provides an important intervention for increasing energy intake in children with volume intolerance or fluid restriction.     

Energy‐Dense Formulae May Slow Gastric Emptying in the Critically Ill

Background: Enteral feed intolerance occurs frequently in critically ill patients and can be associated with adverse outcomes. “Energy‐dense formulae” (ie, >1 kcal/mL) are often prescribed to critically ill patients to reduce administered volume and are presumed to maintain or increase calorie delivery. The aim of this study was to compare gastric emptying of standard and energy‐dense formulae in critically ill patients. Methods: In a retrospective comparison of 2 studies, data were analyzed from 2 groups of patients that received a radiolabeled 100‐mL “meal” containing either standard calories (1 kcal/mL) or concentrated calories (energy‐dense formulae; 2 kcal/mL). Gastric emptying was measured using a scintigraphic technique. Radioisotope data were collected for 4 hours and gastric emptying quantified. Data are presented as mean ± SE or median [interquartile range] as appropriate. Results: Forty patients were studied (n = 18, energy‐dense formulae; n = 22, standard). Groups were well matched in terms of demographics. However, patients in the energy‐dense formula group were studied earlier in their intensive care unit admission (P = .02) and had a greater proportion requiring inotropes (P = .002). A similar amount of calories emptied out of the stomach per unit time (P = .57), but in patients receiving energy‐dense formulae, a greater volume of meal was retained in the stomach (P = .045), consistent with slower gastric emptying. Conclusions: In critically ill patients, the administration of the same volume of a concentrated enteral nutrition formula may not result in the delivery of more calories to the small intestine over time because gastric emptying is slowed.     

Frequent feeding delays the gastric emptying of a subsequent meal

To assess the suitability of the 13C-octanoic acid breath test for measuring gastric emptying in circumstances other than the post-absorptive state, a preliminary study was performed where 6 hourly spaced isoenergetic meals preceded the determination of gastric emptying of a subsequent 2 MJ meal. Emptying was measured in three individuals on four separate occasions, with a reproducibility of 8%. A crossover study was then conducted to test the hypothesis that meal frequency can modulate the gastric emptying of a subsequent meal, with the potential to influence appetite regulation. Sixteen subjects were fed to energy balance, receiving food either as 2 isoenergetic meals 3 h apart or 6 isoenergetic meals fed hourly. Gastric emptying of a subsequent 2 MJ meal was investigated. Visual analogue scales were used throughout to assess appetite. The maximum rate of gastric emptying was unchanged but the onset of emptying was delayed by the more frequent feeding pattern. There was no significant difference in subjective appetite before or after the test meal. In conclusion, short-term increases in feeding frequency delayed the gastric emptying of a subsequent meal, but significant effects on post-meal appetite could not be demonstrated.     

Dietary protein precipitation properties have effects on gastric emptying in healthy volunteers

BACKGROUND & AIMS: Strategies that reduce the size of particles in the stomach accelerate gastric emptying. Partial dephosphorylation of casein reduces the size of protein precipitates (curds) in acid conditions and facilitates peptic digestion. We hypothesized that changing the precipitation properties of casein by partial dephosphorylation would accelerate gastric emptying. METHODS: Eight healthy male volunteers entered a prospective, double blind, randomized study with crossover design. Gastric emptying of milk based formula containing either unmodified or dephosphorylated casein was assessed by scintigraphy. Gastric pH measurements were acquired concurrently. RESULTS: A trend to faster gastric emptying was observed for the unmodified preparation, with lower median half time (unmodified 133; dephosphorylated 214 min, P = 0.09) and area under the curve (unmodified 8425 min%; dephosphorylated 9135 min%, P = 0.08). A positive correlation was found between half time for the dephosphorylated preparation and the treatment effect (r2 = 0.81, P < 0.02). Gastric pH was unaffected. CONCLUSIONS: The study hypothesis was rejected; indeed gastric emptying tended to be faster for the unmodified than the dephosphorylated protein. This effect was more pronounced in subjects with slow gastric emptying on the dephosphorylated preparation. Properties other than the size of protein precipitates determine the rate of gastric emptying for milk based formula.     

Bedside placement of nasojejunal tubes: a randomised-controlled trial of spiral- vs straight-ended tubes

BACKGROUND AND AIMS: The success rate of unguided nasojejunal feeding tube insertion is low, thus often requiring endoscopic or radiological assistance. The spiral end of the Bengmark nasojejunal tube is supposed to aid post-pyloric placement, but no comparative trial has been performed. METHODS: Patients requiring nasojejunal feeding were randomised to have either Medicina (straight) or Bengmark (spiral) nasojejunal tube placed after stratification into those with normal gastric emptying or clinical evidence of delayed gastric emptying. Nasojejunal tubes were placed at the bedside in a standard fashion without radiological guidance by the same person for pre- and/or post-operative feeding. Bolus intravenous metaclopromide (10mg) was given prior to insertion in the abnormal gastric emptying group. Abdominal radiographs were obtained at 4 and 24h, and the primary end-point was jejunal placement at 24h. RESULTS: Forty-seven patients were randomised of which 17 (11 straight, 6 spiral) could not tolerate the nasojejunal tube. Of the 30 remaining patients, 16 had normal gastric emptying. In patients with normal gastric emptying, successful placement at 24h was achieved in 78% (spiral tube), vs 14% (straight tube) (P=0.041). In the abnormal gastric emptying group, success rates were 57% and 0%, respectively (P=0.07). CONCLUSION: Spiral nasojejunal tubes are preferable to straight tubes for bedside unguided post-pyloric feeding in patients with normal gastric emptying.     

Early enteral nutrition in the cardiothoracic intensive care unit

BACKGROUND AND AIMS: Early enteral nutrition (EN) improves intestinal integrity, motility and immunocompetence. However, technical problems such as diarrhoea and gastric residual volumes are said to be associated with the method and have prevented its implementation. We have prospectively assessed clinical problems connected to early EN. PATIENTS AND METHODS: Seventy-three consecutive patients eligible for EN were assessed and observed until discharge from the intensive care unit (ICU) or until they resumed oral nutrition. They had surgery for coronary artery bypass grafting and/or valvular disease, thoracic or thoracoabdominal aortic aneurysms or other combined procedures. Two cardiac patients were not subjected to surgery. RESULTS: In 59/73 patients, EN was started within 3 days. EN was discontinued in half of the patients when they were able to feed themselves. Twelve patients vomited, one of them severely. Dislocation of the nasogastric tube occurred in 28 patients. The 15 patients with diarrhoea were treated with 2-6 broad-spectrum antibiotics during their ICU-stay. Out of 73, 40 patients did not show any gastric residual volume (GRV). GRV decreased during EN in 50% of the patients with fairly large or large residual volumes. The incidence of aspiration pneumonia was 10%. CONCLUSION: In the cardiothoracic ICU, individually adjusted early EN is feasible with few problems.     

The addition of soybean phosphatidylcholine to triglyceride increases suppressive effects on food intake and gastric emptying in rats

The physiologic roles of dietary lecithin have not yet been clearly defined. We examined the effects of soybean lecithin on gastric emptying (Experiments 1 and 2) and food intake (Experiment 3) in rats. Male Wistar rats were fed 2 g of a 20 g lipid/100 g diet containing various levels of lecithin after 24 h of food deprivation; gastric contents were collected 3 h after feeding (Experiment 1). In Experiment 2, the effects of lecithin and a CCK-A receptor antagonist on gastric emptying were examined using a modified phenol red recovery technique. In Experiment 3, their effects on food intake were examined after an intraduodenal infusion of an oil emulsion containing 50 mg soybean oil (SO) or SO partially replaced by lecithin (14-50%). Gastric emptying rates of the lipid and protein in the test diet (Experiment 1) or of phenol red (Experiment 2) were lower in the groups administered lecithin. Food intake for 60 min was lower in rats infused with the oil emulsion containing lecithin (25, 50%) than in rats not administered lecithin. The suppressive effects of lecithin on gastric emptying and food intake were largely reduced by devazepide. These results demonstrate that oil containing lecithin inhibits gastric emptying and food intake, and the effects are associated in part with CCK release.