Determining Feeding Tube Location by Gastric and Intestinal pH Values

Enteral Access Devices: Types, Function, Care, and Challenges

Enteral access feeding devices are placed in patients who have a functional and accessible gastrointestinal (GI) tract but are not able to consume or absorb enough nutrients to sustain adequate nutrition and hydration. For many individuals, enteral nutrition support is a lifesaving modality to prevent or treat a depleted nutrient state that can lead to tissue breakdown, compromised immune function, and poor wound healing. Psychological well-being is also affected with malnutrition and dehydration, triggering feelings of apathy, depression, fatigue, and loss of morale, negatively impacting a patient's ability for self-care. A variety of existing devices can be placed through the nares, mouth, stomach or small intestine to provide liquid nutrition, fluids, and medications directly to the GI tract. If indicated, some of the larger-bore devices may be used for gastric decompression and drainage. These enteral access devices need to be cared for properly to avert patient discomfort, mechanical device-related complications, and interruptions in the delivery of needed nutrients, hydration, and medications. Clinicians who seek knowledge about enteral access devices and actively participate in the selection and care of these devices will be an invaluable resource to any healthcare team. This article will review the types, care, proper positioning, and replacement schedules of the various enteral access devices, along with the prevention and troubleshooting of potential problems.

Naso-enteric Tube Placement: A Review of Methods to Confirm Tip Location, Global Applicability and Requirements

BACKGROUND

The insertion of a tube through the nose and into the stomach or beyond is a common clinical procedure for feeding and decompression. The safety, accuracy and reliability of tube insertion and methods used to confirm the location of the naso-enteric tube (NET) tip have not been systematically reviewed. The aim of this study is to review and compare these methods and determine their global applicability by end-user engagement.

METHODS

A systematic literature review of four major databases was performed to identify all relevant studies. The methods for NET tip localization were then compared for their accuracy with reference to a gold standard method (radiography or endoscopy). The global applicability of the different methods was analysed using a house of quality matrix.

RESULTS

After applying the inclusion and exclusion criteria, 76 articles were selected. Limitations were found to be associated with the 20 different methods described for NET tip localization. The method with the best combined sensitivity and specificity (where n > 1) was ultrasound/sonography, followed by external magnetic guidance, electromagnetic methods and then capnography/capnometry. The top three performance criteria that were considered most important for global applicability were cost per tube/disposable, success rate and cost for non-disposable components.

CONCLUSION

There is no ideal method for confirming NET tip localisation. While radiography (the gold standard used for comparison) and ultrasound were the most accurate methods, they are costly and not universally available. There remains the need to develop a low-cost, easy-use, accurate and reliable method for NET tip localization.

Examining the evidence to guide practice: challenging practice habits

Nurses are the largest segment of the nation's health care workforce, which makes nurses vital to the translation of evidence-based practice as a practice norm. Critical care nurses are in a position to critically appraise and apply best evidence in daily practice to improve patients' outcomes. It is important for critical care nurses to continually evaluate their current practice to ensure that they are applying the current best evidence rather than practicing on the basis of tradition. This article is based on a presentation at the 2013 National Teaching Institute of the American Association of Critical-Care Nurses. Four practice interventions that are within the realm of nursing are critiqued on the basis of current best evidence: (1) turning critically ill patients, (2) sleep promotion in the intensive care unit, (3) feeding tube management in infants and children, and (4) prevention of venothromboembolism…again. The related beliefs, current evidence, and implications for practice associated with each topic are described.

Best evidence: nasogastric tube placement verification

Further research on cost-effective techniques to verify enteral tube placement is warranted using a variety of pediatric populations with differing conditions that may impact gastric pH. It is imperative that clinical facilities review current policies and procedures to ensure that evidence-based findings are guiding nursing practice. Many nurses continue to rely on auscultation to verify NGT placement. Education and competency validation can assist with current practices for NGT placement being consistently incorporated by all personnel in the health care setting. Continuing to search for evidence related to nursing care will guide the direct care RN in providing best practice.

Overcoming the barriers in micellar drug delivery: loading efficiency, in vivo stability, and micelle-cell interaction

IMPORTANCE OF THE FIELD

Spontaneously constructed from block copolymers in aqueous media, the polymer micelle has been extensively studied as a potential carrier of poorly water-soluble drugs, but cellular uptake pathways and stability of micelles in blood have not yet been clearly understood. An in-depth insight into the physical and biological behaviors of polymer micelles is necessitated for designing next-generation micelles.

AREAS COVERED IN THIS REVIEW

This review suggests possible solutions to improve micellar drug loading capacity, scrutinizes the parameters influencing the micelle stability in blood, and also discusses the fate of micelles in cellular and in vivo environment, respectively. Direct and indirect evidences from the literatures mostly published after 90's were collected, analyzed and summarized.

WHAT THE READER WILL GAIN

A critical analysis of micelle's stability in vivo and micelle-cell interaction is provided to highlight the key issues to be addressed to affirm that micelle can properly work as a drug carrier in clinical settings.

TAKE HOME MESSAGE

With a clear understanding of its behaviors in biological environment, the polymer micelle is a promising nanocarrier for chemotherapy.

Bedside postpyloric feeding tube placement: a pilot series to validate this novel technique

OBJECTIVE

Postpyloric feeding may facilitate tolerance to enteral nutrition (EN) and offers an alternative route of feed administration when prepyloric EN fails. However, this is constrained by the difficulty of establishing nasojejunal (NJ) tube placement, which may necessitate endoscopy or radiology with the inevitable delay in the instigation of treatment. A bedside technique of NJ tube insertion has, therefore, been developed to permit blind postpyloric intubation. The primary aim of this audit was to validate the success of bedside NJ tube placement using the described technique. Secondary end points included the time taken to establish EN and the value of aspirate pH as an indicator of tube tip placement.

DESIGN

Observational.

SETTING

District general hospital.

PATIENTS

Consecutive patients requiring EN.

MEASUREMENTS AND MAIN RESULTS

The time taken to insert the tubes, the success rates in achieving the required position, and the time between the decision to feed and commencement of EN were recorded. The pH of any aspirate obtained was related to tube tip placement. Tube position was confirmed radiologically before starting EN. A total of 43 NJ tubes were inserted in 32 patients. Successful postpyloric intubation was achieved in 35 of 43 patients (81%). The median time for tube insertion was 18 (14-30) minutes. Time from the decision to feed to commencement of EN was 6 (5-18) hours. Aspirates were obtained from 26 of 43 (60%) intubations. Gastric aspirate pH readings were obtained for 19 of 43 (44%) of these intubations. Radiology reliably demonstrated the position of the tube tip in all cases.

CONCLUSIONS

By-the-bedside NJ tube placement is possible in more than 80% of patients. This may overcome delays in the commencement of feeds resulting from other methods of postpyloric tube placement. The use of aspirate pH on its own is not a reliable indicator of tube tip position.

Engineered polymers for advanced drug delivery

Engineered polymers have been utilized for developing advanced drug delivery systems. The development of such polymers has caused advances in polymer chemistry, which, in turn, has resulted in smart polymers that can respond to changes in environmental condition such as temperature, pH, and biomolecules. The responses vary widely from swelling/deswelling to degradation. Drug-polymer conjugates and drug-containing nano/micro-particles have been used for drug targeting. Engineered polymers and polymeric systems have also been used in new areas, such as molecular imaging as well as in nanotechnology. This review examines the engineered polymers that have been used as traditional drug delivery systems and as more recent applications in nanotechnology.

Methods for determining the correct nasogastric tube placement after insertion: a meta-analysis

BACKGROUND

Nasogastric tubes are frequently used in the clinical setting for the management of patients who require decompression of the gastrointestinal tract, diagnosis and assessment, nutritional support and medication administration. A variety of bedside methods have been used either individually or in combination to assess NG tube placement.

OBJECTIVES

The objective of this review is to present the best available evidence to support decisions pertaining to methods for determining the correct nasogastric tube placement after insertion.

SEARCH STRATEGY

A literature search was performed using the following databases MEDLINE (1950 to Sept 2008), CINAHL (1982 to Sept 2008), EMBASE (1980 to Sept 2008) and All EBM Reviews (up to 3rd Quarter 2008). Chinese databases searched included WanFang Data (1998 to Sept 2008), China Journal Net (1994 to Sept 2008), Chinese Medical Current Contents (1994 to Sept 2008), Index to Chinese Periodical Literature (1970 to Sept 2008), and the Chinese Biomedical Literature Database (1980 to Sept 2008). In addition the reference lists of relevant trials and conference proceedings were also scrutinised. Investigators were contacted to elicit further information.

SELECTION CRITERIA

Clinical trials, prospective studies, observational studies, case reports, and evaluation studies assessing the diagnostic accuracy of methods for determining the correct placement of nasogastric tube after insertion were considered for inclusion in the meta-analysis.

DATA COLLECTION AND ANALYSIS

Eligibility of the trials for inclusion in the review, details of eligible trials and the methodological quality of the trials were assessed independently by two reviewers. Since not all trials reported true positive, true negative, false positive and false negative rates, these rates were calculated based on the data in the published papers. The two by two tables were reconstructed for each study, and sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio were calculated for each study. Diagnostic studies presenting insufficient data for construction of a two by two table were excluded from statistical analysis, but were included in the narrative part of the review.

MAIN RESULTS

Twenty-six trials were included in this meta-analysis: three trials investigated the effectiveness of colorimetric capnometry in detecting inadvertent airway intubation; three trials reported the use of capnography to verify tube placement in airway and to differentiate between respiratory and GI tube placement; one trial compared the use of a portable capnograph with a disposable colorimetric CO2 indicator in detecting inadvertent respiratory intubation. There were nine trials made use of a variety of cut-off points based on the biochemical measurement parameters of feeding tube aspirates (pH, bilirubin, pepsin and trypsin) in differentiating gastric from respiratory and intestinal placement of feeding tubes; one trial evaluated the accuracy of six pH test-strips. There were nine trials investigated the effectiveness of using various methods to differentiate between respiratory and GI feeding tube placement which included the use of: spring gauge pressure manometer, magnetic detection, sonography, auscultation and visual inspection of aspirates.

AUTHORS' CONCLUSION

The limited evidence obtained from the meta-analysis does not provide a substantial base for the development of practice guidelines. However, based on the trials undertaken to date, there is strong evidence to support the use of capnography or colorimetric capnometry for identification of feeding tube placement in mechanically ventilated patients. Until stronger evidence becomes available practice related to the diagnostic tests used within the clinical setting will continue to be dictated by local preferences and cost factors.

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.