Systemic absorption of food dye in patients with sepsis

Discovering Novel Bioactivities of Controversial Food Additives by Means of Simple Zebrafish Embryotoxicity (ZET) Assays

The rising concerns about controversial food additives' potential hazardous properties require extensive yet animal-minimized testing strategies. Zebrafish embryos are the ideal in vivo model representing both human and environmental health. In this study, we exposed zebrafish embryos to eight controversial food additives. Our results indicate that Sodium Benzoate is a Cat.3 aquatic toxicant, while Quinoline Yellow is a strong teratogen. At high concentrations, non-toxic chemicals induced similar phenotypes, suggesting the impact of ionic strength and the applicability of the darkened yolk phenotype as an indicator of nephrotoxicity. Three food additives showed unpredicted bioactivities on the zebrafish embryos: Brilliant Blue could weaken the embryonic yolk, Quinoline Yellow may interfere with nutrient metabolism, and Azorubine induced precocious zebrafish hatching. In conclusion, the zebrafish embryo is ideal for high throughput chemical safety and toxicity screening, allowing systematic detection of biological effects-especially those unexpected by targeted in vitro and in silico models. Additionally, our data suggest the need to reconsider the safety status of food additives Quinoline Yellow, Brilliant Blue, Sodium Benzoate, and other controversial food additives in further studies, as well as pave the way to further applications based on the newly found properties of Brilliant Blue and Azorubine.

Enhanced pigment content estimation using the Gauss-peak spectra method with thin-layer chromatography for a novel source of natural colorants

Alternative pigment sources that are harmless to human health and can be produced in an eco-responsible way are of great research interest. The experiments undertaken in this study were conducted using autumn leaves of Aesculus hippocastanum as potential novel colorant sources. This study focused on improving the Gauss-peak spectra method (a less expensive alternative to high-pressure liquid chromatography) in combination with thin-layer chromatography, leading to the development of a new methodology. The collected leaves were stored at two different temperatures: 20°C and −20°C. The data obtained by spectrophotometric scanning of the samples were analyzed using the Gauss-peak spectra method in the R program with three wavelength ranges: 350–750 nm, 390–710 nm, and 400–700 nm. The results were then assessed for statistically significant differences in the estimated concentrations for the different wavelength ranges regarding (1) total pigment, carotenoid, and chlorophyll concentration (two-sample t-test) and (2) concentration of each indicated pigment (two-way analysis of variance). The results were also tested for differences between the estimated concentrations of samples stored under the different conditions. The Gauss-peak spectra results with and without thin-layer chromatography were statistically compared using a paired t-test. The results showed that thin-layer chromatography greatly enhanced the efficiency of the Gauss-peak spectra method for estimating the major and minor pigment composition without generating high additional costs. A wavelength range of 400–700 nm was optimal for all Gauss-peak spectra methods. In conclusion, the proposed method is a more successful, inexpensive alternative to high-pressure liquid chromatography.

The color of skin: blue diseases of the skin, nails, and mucosa

Diseases of the skin, hair, nails and mucosa can appear as flesh-colored lesions or may present as any of the colors of the visual spectrum. Diseases associated with blue (or shades of blue) discoloration represent a unique group of conditions that occur de novo or as a reaction to either a topical or a systemic agent to which the individual has been exposed. Blue diseases can affect the skin, the nails or the mucosal membranes of the mouth (buccal mucosa, gingiva, lips, palate or tongue) or eyes (sclera). In addition to appearing blue, they can also appear as blue-black, blue-brown, blue-gray, blue-green, blue-purple, blue-red, and blue-silver. The conditions range from those secondary to exogenous agents (systemic or tattoo or topical) to syndromes to systemic diseases to tumors (adnexal, melanocytic, vascular, or miscellaneous). A comprehensive attempt to include all conditions that have been described as blue (or a shade of blue) has been performed by evaluating the following terms using the medical search engine PubMed: blue and either gingiva, lips, lunula, mucosa, nails, oral, palate, sclera, skin, or tongue. Subsequently, the conditions were organized by color (blue and shades of blue) and within each color by location (skin, nails, oral mucosa and sclera). The results are presented in organized tables; in addition, there is discussion of some of the conditions that are unique to one or more specific locations. In conclusion, 'preserve and cherish the pale blue dot' and remember that a big red rock eater with chrysiasis is the answer to the riddle, "What is big and blue and eats rocks?"

Quantitative Measure of Intestinal Permeability Using Blue Food Coloring

BACKGROUND

Loss of intestinal barrier integrity plays a fundamental role in the pathogenesis of various gastrointestinal diseases and is implicated in the onset of sepsis and multiple organ failure. An array of methods to assess different aspects of intestinal barrier function suffers from lack of sensitivity, prolonged periods of specimen collection, or high expense. We have developed a technique to measure the concentration of the food dye FD&C Blue #1 from blood and sought to assess its utility in measuring intestinal barrier function in humans.

MATERIALS AND METHODS

Four healthy volunteers and 10 critically ill subjects in the intensive care unit were recruited in accordance with an institutional review board approved protocol. Subjects were given 0.5 mg/kg Blue #1 enterally as an aqueous solution of diluted food coloring. Five blood specimens were drawn per subject: 0 h (before dose), 1, 2, 4, and 8 h. After plasma isolation, organic extracts were analyzed by high-performance liquid chromatography/mass spectrometry detecting the presence of unmodified dye.

RESULTS

We found no baseline detectable absorption in healthy volunteers. After including the subjects in the intensive care unit, we compared dye absorption in the six subjects who met criteria for septic shock with the eight who did not. Septic patients demonstrated significantly greater absorption of Blue #1 after 2 h.

CONCLUSIONS

We have developed a novel, easy-to-use method to measure intestinal barrier integrity using a food grade dye detectable by mass spectrometry analysis of patient blood following oral administration.

Aspiration and the Risk of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a major concern in the intensive care unit. It is estimated that the risk of developing VAP may be as high as 1% per ventilated day, and the attributable mortality approaches 50% in some series. A growing body of evidence implicates the role of microaspiration of contaminated oropharyngeal and perhaps gastroesophageal secretions into the airways as an integral step in the pathogenesis of VAP. In patients who have been intubated and mechanically ventilated for >72 hours, the majority of VAP is caused by enteric gram-negative organisms, presumably of gastrointestinal origin. As a result, strategies designed to minimize the risk of these contaminated secretions into the normally sterile airways are of paramount importance in terms of VAP prevention. This review highlights the important etiological role of the gut in the development of VAP and also discusses the evidence behind interventions that may modulate the risk of both aspiration and subsequent VAP.

Brilliant Blue Dyes in Daily Food: How Could Purinergic System Be Affected?

Dyes were first obtained from the extraction of plant sources in the Neolithic period to produce dyed clothes. At the beginning of the 19th century, synthetic dyes were produced to color clothes on a large scale. Other applications for synthetic dyes include the pharmaceutical and food industries, which are important interference factors in our lives and health. Herein, we analyzed the possible implications of some dyes that are already described as antagonists of purinergic receptors, including special Brilliant Blue G and its derivative FD&C Blue No. 1. Purinergic receptor family is widely expressed in the body and is critical to relate to much cellular homeostasis maintenance as well as inflammation and cell death. In this review, we discuss previous studies and show purinergic signaling as an important issue to be aware of in food additives development and their correlations with the physiological functions.

Confirmation of gastric tube bedside placement with the sky blue method

BACKGROUND

The purpose was to review our experiences and determine if applying the sky blue method is reliable in confirming gastric tube (GT) placement in neonates.

METHODS

The study population consisted of 44 infants (55 placements) who were admitted to the Takeda General Hospital between April 2012 and March 2013 and who required GT exchange. The sky blue method using indigo carmine (IC) was indicated for planned tube exchange only. Diluted IC was injected into the gastric space via the old GT just before the tube exchange. The tube was exchanged using a standard method. Then, we checked whether the diluted IC could be collected through the new GT or not.

RESULTS

The reasons for GT placement were a gestational age of < 35 weeks in 31 (56.4%), poor sucking or swallowing disorders in 17 (30.4%), and respiratory disorders in 7 (12.7%) of the 55 placements. GT placement using the sky blue method was considered successful in 52 placements (94.4%), with the remaining 3 placements (5.6%) considered to be failures due to the inability to obtain IC from the gastric space. No adverse events were observed during the tube exchange period.

CONCLUSION

Based on the results, the sky blue method can be considered to be reliable method for the confirmation of GT placement. These results also suggest that the number of radiologic evaluations performed to confirm correct replacement of the GT in infants can be reduced in the future.

Preparation of dye waste-barium sulfate hybrid adsorbent and application in organic wastewater treatment

A new hybrid material was developed by the template-free hybridization of weak acidic pink red B (APRB, C.I. 18073) with BaSO(4). The composition and structure of the material were determined and characterized. In contrast to conventional sorbents, the hybrid material has a specific surface area of 0.89 m(2)/g, but it contains lots of negative charges and lipophilic groups as the basis of specific adsorption. The efficient removal of cationic dyes and persistent organic pollutants (POPs) indicates that it has an improved adsorption capacity and selectivity with a short removal time less than 2 min; while the hybrid sorbents fit the Langmuir isotherm model, and follow the octanol-water partition law. Instead of using APRB reagent, an APRB-producing wastewater was reused to prepare the cost-effective sorbent, and the equilibrium adsorption capacities of which reached 222 and 160 mg/g for EV and BPR, respectively. The sorbents was then used to treat three wastewater samples with satisfactory results of over 97% decolonization and 88% COD-decreasing. In addition, the hybrid sorbent was regenerated from sludge over five cycles, and its adsorption capacity was not appreciably changed. This work has developed a simple and eco-friendly method for synthesizing a practical and efficient sorbent.

Preparation, Characterization and Application of Silver Chloride-Eosin Y Inclusion Material

From the adsorptive precipitation of Cl–, eosin Y (EY) and Ag+, we developed in-situ inclusion of EY into growing silver chloride particles to form ternary electronegative micro-conductors. The composition of the particles was determined by inductively coupled plasma atomic emission spectrometry (ICP-OES), ion chromatography (IC) and spectrophotometry and the size and pattern of the particles characterized by the particle size analysis, X-ray diffractometer (XRD), scanning electron microscopy (SEM), and thermogravimetry. The results showed that the in-situ inclusion of EY into AgCl crystal particles in layer-by-layer and the supermolecular complex {[(AgCl)50EY]n}2n– was formed in cubic and globe-like shape. The ternary inclusion particles adsorbed cationic dyes selectively, rapidly and with high efficiency. A representative cationic dye, victoria blue B (VBB), was used to investigate the performance of the ternary particles as adsorbents and the mechanism involved. The equilibrium adsorption capacity of the ternary particles is 353 mg/g VBB, over 10 times higher than absorption to the silver chloride–only particles and over 3 times to activated carbon. Moreover, the adsorption approached the equilibrium in 10 min, which is much less than that with activated carbon in about 2 h. This work advanced a sample method for preparation of the supramolecular inclusion materials as dye adsorbent and it provided a simple, efficient and practical approach for the recovery or removal of organic substances from aqueous.

Preparation of calcium oxalate-bromopyrogallol red inclusion sorbent and application to treatment of cationic dye and heavy metal wastewaters

BACKGROUND, AIM, AND SCOPE

Dye pollutants are a major class of environmental contaminants. Over 100,000 dyes have been synthesized worldwide and more than 700,000 tons are produced annually and over 5% are discharged into aquatic environments. The adsorption or sorption is one of the most efficient methods to remove dye and heavy metal pollutants from wastewater. However, most of the present sorbents often bear some disadvantages, e.g. low sorption capacity, difficult separation of spoil, complex reproduction, or secondary pollution. Development of novel sorbents that can overcome these limitations is desirable.

MATERIALS AND METHODS

On the basis of the chemical coprecipitation of calcium oxalate (CaC(2)O(4)), bromopyrogallol red (BPR) was embedded during the growing of CaC(2)O(4) particles. The ternary C(2)O(4) (2-)-BPR-Ca(2+) sorbent was yielded by the centrifugation. Its composition was determined by spectrophotometry and AAS, and its structure and morphology were characterized by powder X-ray diffraction (XRD), laser particle-size analysis, and scanning electron microscopy (SEM). The adsorption of ethyl violet (EV) and heavy metals, e.g. Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) were carried out and their removal rate determined by spectrophotometry and ICP-OES. The adsorption performance of the sorbent was compared with powder activated carbon. The Langmuir isothermal model was applied to fit the embedment of BPR and adsorption of EV.

RESULTS

The saturation number of BPR binding to CaC(2)O(4) reached 0.0105 mol/mol and the adsorption constant of the complex was 4.70 x 10(5) M(-1). Over 80% of the sorbent particles are between 0.7 and 1.02 microm, formed by the aggregation of the global CaC(2)O(4)/BPR inclusion grains of 30-50 nm size. Such a material was found to adsorb cationic dyes selectively and sensitively. Ethyl violet (EV) was used to investigate the adsorption mechanism of the material. One BPR molecule may just bind with one EV molecule. The CaC(2)O(4)/BPR inclusion material adsorbed EV over two times more efficiently than the activated carbon. The adsorption of EV on the CaC(2)O(4)/BPR inclusion sorbent was complete in only 5 min and the sedimentation complete in 1 h. However, those of EV onto activated carbon took more than 1.5 and 5 h, respectively. The treatment of methylene blue and malachite green dye wastewaters indicated that only 0.4% of the sorbent adsorbed over 80% of color substances. Besides, the material can also adsorb heavy metals by complexation with BPR. Over 90% of Pb(2+), and approximately 50% of Cd(2+) and Cu(2+), were removed in a high Zn(2+)-electroplating wastewater when 3% of the material was added. Eighty-six percent of Cu(2+), and 60% of Ni(2+) and Cd(2+), were removed in a high Cd(2+)-electroplating wastewater.

DISCUSSION

The embedment of BPR into CaC(2)O(4) particles responded to the Langmuir isothermal adsorption. As the affinity ligand of Ca(2+), BPR with sulfonic groups may be adsorbed into the temporary electric double layer during the growing of CaC(2)O(4) particles. Immediately, C(2)O(4) (2-) captured the Ca(2+) to form the CaC(2)O(4) outer enclosed sphere. Thus, BPR may be released and embedded as a sandwich between CaC(2)O(4) layers. The adsorption of EV on the sorbent obeyed the Langmuir isothermal equation and adsorption is mainly due to the ion-pair attraction between EV and BPR. Different from the inclusion sorbent, the activated carbon depended on the specific surface area to adsorb organic substances. Therefore, the adsorption capacity, equilibrium, and sedimentation time of the sorbent are much better than activated carbon. The interaction of heavy metals with the inclusion sorbent responded to their coordination.

CONCLUSIONS

By characterizing the C(2)O(4) (2-)-BPR-Ca(2+) inclusion material using various modern instruments, the ternary in situ embedment particle, [(CaC(2)O(4))(95)(BPR)]( n ) (2n-), an electronegative, micron-sized adsorbent was synthesized. It is selective, rapid, and highly effective for adsorbing cationic dyes and heavy metals. Moreover, the adsorption is hardly subject to the impact of electrolytes.

RECOMMENDATIONS AND PERSPECTIVES

The present work provides a simple and valuable method for preparing the highly effective adsorbent. If a concentrated BPR wastewater was reused as the inclusion reactant, the sorbent will be low cost. By selecting the inclusion ligand with a special structure, we may prepare some particular functional materials to recover the valuable substances from seriously polluted wastewaters. The recommended method will play a significant role in development of advanced adsorption materials.

Complications related to feeding tube placement

PURPOSE OF REVIEW

Blind placement of a feeding tube can result in serious complications. Given the widespread use of tube feedings, even a small percentage of such problems can affect a significant number of people. The purpose of this review is to describe recent reports of feeding tube placement problems and to examine possible solutions.

RECENT FINDINGS

Multiple case reports of complications of malpositioned feeding tubes continue to surface; most are due to inadvertent placement in the respiratory tract. A tube with feeding ports in the esophagus significantly increases risk for aspiration, as does the displacement of a small bowel tube into the stomach of a patient with significantly slowed gastric motility. Isolated reports of a nasally placed tube entering the brain following head injury continue to occur, as do reports of esophageal and gastric perforation in neonates. A recent study showed that malpositioned tubes are not routinely recorded in risk management databases; it further demonstrated that a comprehensive intervention to reduce complications from small-bore nasogastric feeding tubes was effective.

SUMMARY

Complications related to malpositioned feeding tubes are usually preventable. Poor reporting of feeding tube placement errors hinders the adoption of effective protocols to prevent such errors.

Acute complications associated with bedside placement of feeding tubes

Several types of feeding tubes can be placed at a patient's bedside; examples include nasogastric, nasointestinal, gastrostomy, and jejunostomy tubes. Nasoenteral tubes can be placed blindly at bedside or with the assistance of placement devices. Nasoenteric tubes can also be placed via fluoroscopy and endoscopy. Gastrostomy and jejunostomy tubes can be placed using endoscopic techniques. This paper will describe the indications and contraindications for different types of tubes that can be placed at the bedside and complications associated with tube placement. Complications associated with nasoenteral tubes include inadvertent malpositioning of the tube, epistaxis, sinusitis, inadvertent tube removal, tube clogging, tube-feeding-associated diarrhea, and aspiration pneumonia. Complications from percutaneous gastrostomy and jejunostomy tube placements include procedure-related mishaps, site infection, leakage, buried bumper syndrome, tube malfunction, and inadvertent removal. These complications will be reviewed, along with a discussion of incidence, cause, treatment, and prevention approaches.

Fiberoptic endoscopic evaluation of swallowing (FEES) with and without blue-dyed food

The purpose of this prospective study was to determine if fiberoptic endoscopic evaluation of swallowing (FEES) maintains high intra- and interrater reliability in detecting pharyngeal dysphagia and aspiration without the addition of FD&C Blue No. 1 to food. Twenty consecutive adults referred for a swallow evaluation participated. Nine subjects received blue-dyed food and 11 subjects received regular nondyed food, i.e., yellow pudding and white skim milk. Four variables were rated: (1) the stage transition characterized by depth of bolus flow to at least the vallecula prior to the pharyngeal swallow; (2) evidence of bolus retention in the vallecula or pyriform sinuses after the pharyngeal swallow; (3) laryngeal penetration defined as material in the laryngeal vestibule but not passing below the level of the true vocal folds either before or after the pharyngeal swallow; and (4) tracheal aspiration defined as material below the level of the true vocal folds either before or after the pharyngeal swallow. Three speech-language pathologists experienced in interpreting FEES results independently and blindly reviewed the digitized videotape three times. Intrarater agreements for the four variables with blue-dyed and non-blue-dyed food trials were 100% and monochrome trials ranged from 95% to 100%. Average kappa values for interrater reliability ranged from moderate to excellent agreement (0.61-1.00) for all viewing conditions. Kappa values for blue-dyed trials versus monochrome trials were 0.83 and for non-blue-dyed trials versus monochrome trials were 0.88, indicative of excellent reliability under both viewing conditions. FEES maintains both high intra- and interrater reliability in detecting the critical features of pharyngeal dysphagia and aspiration using either blue-dyed or non-blue-dyed foods. The endoscopist, therefore, can be assured of reliable FEES results using regular, non-dyed food trials.

Adsorption treatment and recovery of the hazardous dye, Brilliant Blue FCF, over bottom ash and de-oiled soya

Two waste materials-bottom ash, a power plant waste, and de-oiled soya, an agricultural waste-are meticulously and successfully used as adsorbent for the removal and recovery of a hazardous triphenylmethane dye, Brilliant Blue FCF. Both the materials were characterized by chemical analysis, IR, DTA, SEM and XRD studies. Their physical characteristics like surface area, porosity, density and loss on ignition were also determined. The adsorption of the dye over both materials was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature, etc. conditions. For both the systems Langmuir and Freundlich adsorption isotherm models were applied and, based on these models, useful thermodynamic parameters were calculated. For both the adsorbents, the kinetic measurements indicate that the adsorption process follows first order kinetics and film diffusion and particle diffusion mechanisms are operative at lower and higher concentrations, respectively, in each case. By percolating the dye solution through fixed-bed columns the bulk removal of the Brilliant Blue FCF was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of Brilliant Blue FCF was made by eluting dilute NaOH of pH 11 through each column.

Toxicity of Food Drug and Cosmetic Blue No. 1 dye in critically ill patients

Food Drug and Cosmetic Blue No. 1 dye (FD&C Blue No. 1) is commonly added to enteral nutrition formulations in order to facilitate the detection of gastric aspirate in tracheal secretions of critically ill patients. However, reports of systemic blue dye absorption and associated adverse outcomes are emerging. We report two cases of abnormal systemic absorption of FD&C Blue No. 1 in critically ill patients who subsequently died of refractory shock and metabolic acidosis. Risk factors and mechanisms of FD&C Blue No. 1 toxicity are discussed, and alternate approaches to gastric aspiration detection in critically ill patients are considered.

Sepsis from Pseudomonas aeruginosa pneumonia decreases intestinal proliferation and induces gut epithelial cell cycle arrest

OBJECTIVES

To evaluate whether the up-regulation in sepsis-induced gut epithelial apoptosis is balanced by an increase in intestinal proliferation and to assess mechanisms affecting the gut's regenerative response to overwhelming infection.

DESIGN

Prospective, randomized, controlled study.

SETTING

Animal laboratory in a university medical center.

INTERVENTIONS

Mice were subjected to intratracheal injection of Pseudomonas aeruginosa and killed between 1.5 and 24 hrs after induction of pneumonia-induced sepsis to assess for gut epithelial proliferation and cell division and for apoptosis. Animals were compared with sham-operation controls, septic transgenic mice that overexpress Bcl-2 throughout their small intestinal epithelium, and septic p53-/- mice.

MEASUREMENTS AND MAIN RESULTS

Proliferation and cell division were assessed by measuring S-phase and M-phase cells in intestinal crypts. The number of S-phase cells showed a progressive decline at all time points measured, with a 5-fold decrease in proliferation between control animals and septic mice 24 hrs after intratracheal injection of pathogenic bacteria (p <.0001). In contrast, cells in M-phase remained constant for the first 12 hrs after the onset of sepsis, but increased nearly 50% at 24 hrs after instillation of P. aeruginosa (p <.005). Both the decrease in S-phase cells and the increase in M-phase cells were partially suppressible in Bcl-2 overexpressors, but cellular proliferation and division were similar between septic p53-/- and p53+/+ mice. Crypt apoptosis was increased at all time points, with maximal death occurring between 12 and 24 hrs.

CONCLUSIONS

Sepsis from P. aeruginosa pneumonia induces a p53-independent decrease in gut epithelial proliferation. Despite an increase in sepsis-induced intestinal apoptosis, there is no compensatory increase in intestinal epithelial proliferation, and there is evidence of a cell cycle block with an accumulation of cells in M-phase. Decreasing gut apoptosis by overexpression of Bcl-2 is associated with a partial reversal of the effect of sepsis on the cell cycle.

The incidence and immediate respiratory consequences of pulmonary aspiration of enteral feed as detected using a modified glucose oxidase test

Pulmonary micro-aspiration of enteral feed in intubated critically ill patients has been reported to occur commonly. In this prospective observational study the incidence of micro-aspiration, diagnosed by a modified glucose oxidase test, is reported in 25 enterally fed critically ill and tracheally intubated patients on a general intensive care unit. Episodes of microaspiration were correlated with changes in PaO2/FiO2 ratio as an index of changes in degree of lung injury. The modified glucose oxidase test differs from the traditional glucose oxidase test because of the enrichment of the feed with glucose (10 g glucose added to 500 ml enteral feed resulting in a tenfold increase in glucose concentration). Pulmonary aspiration of feed was detected by exposing a glucose oxidase strip to tracheal secretions. The feed was enriched with glucose to improve the ability of the reagent strip to detect the feed. The incidence of aspiration of feed was 44% with a prevalence of 6.9% per day of intubation. Only 43% of these episodes of aspiration were detected by the feed being seen in the tracheal secretions. Aspiration was associated with a mean fall in the PaO2/FiO2 ratio of 5.6 kPa from 27.1 kPa to 21.5 kPa (P = 0.002). Aspiration of enteral feed is common and causes a demonstrable morbidity. Detection using this simple bedside test may alert the clinician to institute measures to minimize further aspiration.

Detection of aspiration in enterally fed patients: a requiem for bedside monitors of aspiration

BACKGROUND

Pulmonary aspiration of gastric and oropharyngeal contents is common in enterally fed patients. Detection of early aspiration in these patients has relied on clinical impression, the coloring of enteral feedings with dyes, and less commonly the detection of elevated glucose in tracheal aspirates. The potential benefits, risks, and clinical use of bedside monitors of aspiration are under increasing scrutiny.

METHODS

Literature review. Although this review reflects the opinions of the authors, recommendations of an expert consensus panel (North American Summit on Aspiration, which included one author, J. P. Maloney) were also used to guide recommendations. The specific recommendations of that panel are presented elsewhere.

RESULTS

No large prospective clinical trials have been done to evaluate the use and safety of bedside monitors for aspiration. Clinical impression remains a poor "gold standard" of aspiration diagnosis in enterally fed patients. The coloring of enteral feedings with blue dyes (chiefly FD&C Blue No.1) is ubiquitous in hospitals despite evidence that it is not sensitive and potentially harmful. Cases of absorption of blue dye from enteral feedings in patients with critical illness have raised concern about the safety of the blue dye method, particularly in light of apparent toxic effects of these dyes on mitochondria. The glucose detection method has not been embraced; it too has little use and is labor intensive.

CONCLUSIONS

Use of colored dyes in enteral feedings and glucose detection methods should be abandoned. Nonrecumbent positioning is an evidenced-based method for aspiration prevention that needs to be re-emphasized. Novel bedside methods of detecting early aspiration are needed to supplement preventative strategies.

Future considerations in aspiration pneumonia in the critically ill patient: what is not known, areas for future research, and experimental methods

The medical literature supports the use of enteral feeding to provide nutrition and improve patient outcomes. A major complication of enteral feeding is aspiration and associated morbidity and mortality. Many knowledge gaps exist that inhibit our ability to define and diagnose aspiration, identify patients at risk, and develop prevention techniques. Several areas of inquiry should be explored to help us define and prevent the disorder--for instance, standardized criteria should be developed for diagnosing aspiration pneumonia and for differentiating it from other types of pneumonia, and accurate tests should be devised for detecting it. Research also is needed to evaluate the influence of (1) various enteral feeding sites on aspiration risk, (2) the effects of risk reduction techniques such as selective decontamination and use of promotility agents, and (3) potential benefits of immunonutrition. Current parameters used in decisions about when to initiate enteral feeding in critically ill patients are defined.

Efficacy of dye-stained enteral formula in detecting pulmonary aspiration

STUDY OBJECTIVE

To determine the extent to which a mixture of human gastric juice and enteral formula stained with two concentrations of FD&C Blue No. 1 food dye (0.8 and 1.5 mL/L) is visible in suctioned tracheobronchial secretions following three forced small-volume pulmonary aspirations over a 6-h period in an animal model.

DESIGN

Experimental 2 x 3 repeated measures.

SETTING

Animal laboratory and an acute care hospital.

PARTICIPANTS

Ninety New Zealand white rabbits weighing approximately 3 kg each, and 90 acutely ill adults who furnished gastric juice.

INTERVENTIONS

A mixture of human gastric juice and enteral formula stained with 0.8 or 1.5 mL of dye per liter was instilled intratracheally over a 30-min period into anesthetized intubated animals at baseline, 2 h, and 4 h. A total of 0.4 mL/kg of the mixture was instilled at each session. Ninety minutes after each instillation, suctioned secretions were examined for visible dye and blood.

MEASUREMENTS AND RESULTS

Dye was visible in 46.3% of the secretions (125 of 270). The concentration of dye had no significant effect on dye visibility. Blood that was present in 114 of 270 of the secretions (42.2%) interfered with dye visibility in all but two secretions. For reasons unknown, even in the absence of blood, dye visibility decreased from 90.2% (55 of 61 secretions) after the first aspiration event to only 61% (25 of 41 secretions) after the third aspiration event.

CONCLUSIONS

Findings from this animal model study do not support the use of the dye method to detect repeated small-volume aspirations. For clinicians who choose to use the dye method in selected situations, it appears that a dye concentration of 0.8 mL/L may be as effective in detecting aspiration as a 1.5 mL/L concentration.

Green urine in a critically ill patient

The development of discolored urine in the critically ill patient, although uncommon, may have many possible causes, with the most likely source related to medication administration. Studies were undertaken in a 39-year-old man who developed dark green urine while in the intensive care unit for neutropenic sepsis. Although the patient had developed prior nonoliguric renal failure stemming from his sepsis, his renal function at the time of presentation of urine discoloration was considered normal. Review of his medications and intravenous infusions suggested the most likely cause was the food dye placed in his enteral tube feedings. Spectrophotometric evaluation of the urine confirmed the presence of Food Dye and Color Blue Number 1 (FD&C Blue No. 1). This case shows that significant gastrointestinal absorption of FD&C Blue No. 1 can occur. FD&C Blue No. 1 should be considered in the differential diagnosis of dark green discolored urine.

Green skin discoloration associated with multiple organ failure

OBJECTIVE

To report intense green hyperpigmentation related to FD & C Blue No. 1.

DESIGN

Retrospective case review.

SETTING

Surgical intensive care unit.

PATIENT

A 67-yr-old woman with unstable angina, electrocardiographic S-T segment elevation, and a left ventricle thrombus requiring emergent coronary revascularization surgery.

INTERVENTIONS

Postoperative monitoring and treatment for multiple organ dysfunction that included small-bowel tube feeding and propofol sedation.

MEASUREMENTS AND MAIN RESULTS

The patient developed an intense green skin color.

CONCLUSION

Patients with multiple organ failure may be at risk for unusual pigmentation effects from tube feeding dyes.

Pepsin as a Marker for Pulmonary Aspiration

• Background Although assessment for aspiration of small volumes of gastric contents in tube-fed patients receiving mechanical ventilation is important, available methods for this purpose are not wholly satisfactory. A potential method is immunoassay of tracheal secretions for the gastric enzyme pepsin.

• Objectives To determine the frequency with which pepsin in suctioned tracheal secretions from acutely ill, tube-fed patients receiving mechanical ventilation could be detected via an immunoassay.

• Methods A convenience sample of 136 specimens of suctioned tracheal secretions was collected from 30 acutely ill, tube-fed adults receiving mechanical ventilation. Multiple samples were obtained from 26 of the 30 patients (range, 2–11 per subject). An immunoassay with rooster polyclonal antibodies to purified human pepsin was used to detect pepsin in the secretions.

• Results Fourteen specimens tested positive for pepsin. Secretions from 5 patients accounted for the 14 pepsin-positive results. A significant relationship was found between the position of the head of the bed and the presence of pepsin in tracheal secretions (P&lt; .001). Of the 14 pepsin-positive specimens, 13 (92.9%) were obtained from subjects in a flat position.

• Conclusions A pepsin immunoassay can be used to detect pepsin in human tracheal secretions. If pepsin in tracheal secretions is considered an indicator of aspiration of gastric contents, aspiration occurred in 5 of the 30 subjects. A flat position is strongly associated with the presence of pepsin in tracheal secretions.

Overexpression of Bcl-2 in the intestinal epithelium improves survival in septic mice

OBJECTIVES

The aim of this study was to determine whether decreasing intestinal epithelial apoptosis in sepsis would alter mortality rates. The roles of the antiapoptotic protein Bcl-2 and the "executioner" protease caspase-3 in sepsis-induced gut cell death also were evaluated.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Animal laboratory in an academic medical center.

INTERVENTIONS

Transgenic mice that overexpress Bcl-2 throughout the small intestinal epithelium (n = 23) and littermate controls (n = 27) were subjected to cecal ligation and puncture (CLP) and followed for 8 days to assess survival. A second group of transgenic (n = 15) and littermate animals (n = 15) were subjected to CLP and were killed between 16 and 48 hrs postoperatively to assess for intestinal apoptosis and active caspase-3 staining.

MEASUREMENTS AND MAIN RESULTS

Survival of transgenic animals was 83% 8 days after CLP compared with 44% for littermate controls (p < .005). Survival curves between the two groups of animals began diverging within 24 hrs. Overexpression of Bcl-2 was associated with a significant decrease in apoptosis between 16 and 24 hrs post-CLP (p < .05) as well as decreased staining for active caspase-3.

CONCLUSIONS

Decreasing intestinal epithelial cell death via overexpression of Bcl-2 improves survival in septic mice. The gut may play a central role in the pathophysiology of sepsis.

Detection of pepsin and glucose in tracheal secretions as indicators of aspiration in mechanically ventilated children

OBJECTIVES

The detection of glucose in tracheal secretions has been used as an indicator of aspiration in mechanically ventilated, tube-fed children. Pepsin detection may be a more specific indicator. We determined the frequency of pepsin and glucose detection in tracheal secretions of mechanically ventilated children and studied the relationships between tracheal secretion pepsin and glucose and clinical evidence of gastroesophageal reflux.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

PATIENTS

A convenience sample of mechanically ventilated children.

INTERVENTIONS

Tracheal secretions were collected at the time of routine endotracheal tube suctioning. Tracheal aspirate glucose concentrations were assessed by using glucose oxidase reagent strips. Tracheal aspirate pepsin was detected by laboratory immunoassay.

MEASUREMENTS AND MAIN RESULTS

One hundred tracheal aspirates were collected from 37 children. Pepsin (>or=1 microg/mL) was detected in nine aspirates, and glucose (>or=20 mg/dL) was detected in 59 aspirates. Overall, five (13.5%) patients had at least one pepsin-positive aspirate, and 33 (89%) had at least one glucose-positive aspirate. Patients with at least one pepsin-positive aspirate were more likely to have clinical evidence of gastroesophageal reflux than patients with pepsin-negative aspirates (5 of 5 vs. 9 of 32, p <.01, Fisher's exact test). Tracheal aspirate glucose positivity was unrelated to the administration of tube feedings and gastroesophageal reflux. No relationship between pepsin and glucose positivity was observed.

CONCLUSIONS

Pepsin is detectable in tracheal secretions of mechanically ventilated children at risk for aspiration. Elevated glucose concentrations in tracheal secretions can occur by mechanisms other than aspiration of glucose-rich formula. Pepsin may be a more specific marker for aspiration than glucose.