A controlled comparison of traditional feeding tube verification methods to a bedside, electromagnetic technique

Ultrasound to Verify Gastric Tube Position in Infants and Children: A Systematic Review

BACKGROUND

Placement of gastric tubes is commonly performed in infants and children but malpositioning is common and is associated with significant complications.

OBJECTIVE

The aim of this systematic review is to identify the evidence on the use of ultrasound to verify correct gastric tube placement in infants and children and gaps in the research.

METHODS

This review was performed using CINAHL, PUBMED, EMBASE and Web of Science databases. Studies were included if they used an empirical study design, were published in English, included infants or children, and evaluated the use of ultrasound to verify correct gastric tube placement compared to radiograph. Sensitivity, specificity, positive and negative predictive values were evaluated.

RESULTS

Four articles were included in the review. Sensitivity estimates were 0.88 to 1.00 and a positive predictive value of 0.99 was reported in one study. Specificity was not reported in any of the included studies. Ultrasound may be an important method to correctly identify gastric tube placement in infants and children with less radiation exposure and cost.

IMPLICATIONS FOR PRACTICE

Ultrasound could be a used to verify gastric tube positioning in infants and children for both initial placement and continued verification leading to reduced radiation exposure and cost.

IMPLICATIONS FOR RESEARCH

Research should focus on evaluating ultrasound specificity and the clinical feasibility of using ultrasound as a standard practice, including cost and time required to complete the exam, as well as the ability of ultrasound to verify gastric tube placement in infants weighing less than 1500 grams.

Accuracy of the combined method (auscultation and pH measurement) and ultrasonography for confirmation of gastric tube placement: a study protocol for a prospective study

INTRODUCTION

Patients using a nasogastric tube (NGT) are vulnerable to adverse events, therefore proper assessment of these patients, verification of the correct tube placement and constant monitoring by the nursing staff are strategies that can reduce adverse events and risks associated with the care. The aim of this study will be to assess the accuracy of the combined method (auscultation and pH measurement) and ultrasonography for confirmation of gastric tube placement compared with the X-ray method. A further aim will be to measure and provide evidence for the direct costs of each method of confirming NGT placement and to evaluate the impact of each method on the mean direct cost of the patient.

METHODS AND ANALYSIS

This is a prospective, single-centre study of diagnostic accuracy. Data will be collected in the clinical and surgical wards, intensive care unit and coronary care unit of a Brazilian teaching hospital. The sample will consist of 385 assessments, performed in adult patients that agree to participate in the study and that receive an NGT. The combined method and the ultrasound will be the index tests and will be performed on all study participants for later comparison with an X-ray examination, considered the reference standard and the gold standard to distinguish between gastric and pulmonary placement. Sensitivity, specificity, positive predictive value and negative predictive value will be calculated to assess the diagnostic accuracy of the methods investigated in this study, with Cohen's kappa analysis used to evaluate the degree of concordance.

ETHICS AND DISSEMINATION

The study was approved by the Research Ethics Committee of the University of São Paulo at Ribeirão Preto College of Nursing, registration number: 83087318.4.0000.5393. The findings will be reported through academic journals, seminars and conference presentations, social media, print media, the internet and community/stakeholder engagement activities.

Devices and Techniques for Bedside Enteral Feeding Tube Placement

Enteral feedings are an integral part of care for many hospitalized patients. Accessing the gastrointestinal (GI) tract safely and in a timely manner can be challenging. Various techniques and devices to enhance the safety of bedside feeding tube placement are available for clinicians. Three specific devices are highlighted, including the colorimetric CO(2) detector (CCD), a magnetically guided feeding tube (MGFT), and the electromagnetic tube placement device (ETPD). The CO(2) detector is applied to detect the presence or absence of CO(2), thus assisting in correct placement of the feeding tube tip into the GI tract vs the lung. The MGFT uses a magnetic device to manipulate the feeding tube through the GI tract into the small intestine. The ETPD provides real-time visualization of the feeding tube as it progresses into the small intestine. Training and repetition are essential for safe and successful feeding tube placement, and the highlighted devices can contribute to both of these goals.

Monitoring Feeding Tube Placement

The purpose of this literature review is to describe currently available bedside methods to determine feeding tube placement. Described first are methods used at the time of blind insertion to distinguish between gastric and respiratory placement and gastric and small-bowel placement. Discussed next are methods used after feedings are initiated to determine if the tube has remained in the desired position in the gastrointestinal tract. Some of the methods are research-based, whereas others are opinion-based. The level of accuracy of the methods discussed in the review varies widely. No sure non-radiographic method exists to differentiate between respiratory, esophageal, gastric, and small bowel placement of blindly inserted feeding tubes in the fed or unfed state. However, a combination of some of the simpler and more accurate methods may be used to guide feeding tube placement during insertion and help identify the point at which an abdominal radiograph is most likely to confirm the desired location. In addition, methods described in this review can help determine when a radiograph is needed to confirm that a feeding tube has remained in the correct position after the initiation of feedings. Minimizing the number of radiographs taken to assure correct tube placement is important, especially in young children and in the critical care setting where the need for radiographs for other reasons is common.

Noninvasive Verification of Nasogastric Tube Placement Using a Magnet-Tracking System: A Pilot Study in Healthy Subjects

BACKGROUND

Fluoroscopic verification of nasogastric (NG) feeding tube placement is inconvenient and involves radiation exposure. We tested whether the position of an NG tube can be assessed reliably by a recently introduced magnet-tracking system.

METHODS

A small permanent magnet was attached at the end of an NG tube and its position was monitored using an external sensor array connected to a computer. NG tube trajectory, spontaneous movements of the magnet, and its position relative to the lower esophageal sphincter (LES) and xiphisternum were assessed in 22 healthy subjects and compared with esophageal manometry. In 12 subjects, localization of the magnet was also compared with fluoroscopy.

RESULTS

Magnet-tracking displayed NG tube tip movement reproducibly as it moved vertically in the esophagus and then laterally into the stomach. Compared with manometry, the accuracy and sensitivity of magnet tracking for localization of the NG tube tip, above or below the diaphragm, were 100%. Compared with fluoroscopy, the accuracy of NG tube localization by magnet tracking was 100%. With the magnet in the stomach, but not in the esophagus or LES, low amplitude displacements at a frequency of 3 per minute, consistent with gastric slow wave activity, were observed.

CONCLUSIONS

Magnet tracking allows accurate, real-time, 3-dimensional localization of an NG tube with respect to anatomic landmarks. Recorded motor patterns are indicative of the position of the NG tube. Magnet tracking may be a useful tool for bedside placement of nasogastric and enteral feeding tubes.

Does Bedside Sonography Effectively Identify Nasogastric Tube Placements in Pediatric Critical Care Patients?

BACKGROUND

A nasogastric tube (NGT) insertion is a common procedure in intensive care units, with some serious complications that result from the malposition of the NGT tip. This pilot study was designed to investigate the efficiency of ultrasound in verifying correct NGT placement and to compare these results with radiographic findings.

MATERIALS AND METHODS

This was a single-center, double-blind prospective study of patients who had received an NGT in the pediatric critical care unit. Twenty-one patients aged 1 month to 18 years were included in this study. All NGTs were inserted by the same critical care physician. After insertion, the physician first confirmed NGT placement by the auscultation of the epigastrium following the insufflation of air. Confirmation was supplemented with an abdominal radiograph. A radiologist who was unaware of the radiographic findings performed bedside sonography on all patients and verified the location of the NGTs. The findings from these 2 physicians were then compared.

RESULTS

NGTs were inserted without any complications, and none of the NGTs were positioned in the respiratory tract in any of the patients. All NGT tips were visualized by radiography and sonography with a sensitivity of 100%.

CONCLUSION

Bedside sonography performed by a radiologist is an effective and sensitive diagnostic procedure for confirming the correct NGT position in patients in the pediatric critical care unit.

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.

Electromagnetic Guided Postpyloric Tube Placement in Children: A Feasible and Promising Technique

OBJECTIVES

Postpyloric feeding tube (PPFT) placement can be cumbersome. Fluoroscopic and endoscopic placements are required when unguided placement fails. We aimed to evaluate the feasibility and safety of PPFT placement in children, using an electromagnetic (EM) guided system as a rescue strategy in case unguided tube insertion fails.

METHODS

In a single-center prospective study, we included all the children (weight >2.5 kg) in whom unguided PPFT placement failed between 2009 and 2012. EM guided PPFT placement was attempted before regular fluoroscopic and endoscopic placement was attempted, respectively.

RESULTS

Forty-nine children were included (mean age 3.5 years). EM guided PPFT placement was successful in 82% of the children. No adverse events occurred. Age or indication for the PPFT did not influence the success rate of the procedure. A trend of a learning curve of 25 patients was noticed. Costs of EM placement were slightly higher than those of fluoroscopic placement in our hospital setting.

CONCLUSION

With enough expertise, EM guided PPFT placement seems safe and can prevent fluoroscopic or endoscopic tube placement in 82% of children.

A Non-invasive Real-time Localization System for Enhanced Efficacy in Nasogastric Intubation

Nasogastric (NG) intubation is one of the most commonly performed clinical procedures. Real-time localization and tracking of the NG tube passage at the larynx region into the esophagus is crucial for safety, but is lacking in current practice. In this paper, we present the design, analysis and evaluation of a non-invasive real-time localization system using passive magnetic tracking techniques to improve efficacy of the clinical NG intubation process. By embedding a small permanent magnet at the insertion tip of the NG tube, a wearable system containing embedded sensors around the neck can determine the absolute position of the NG tube inside the body in real-time to assist in insertion. In order to validate the feasibility of the proposed system in detecting erroneous tube placement, typical reference intubation trajectories are first analyzed using anatomically correct models and localization accuracy of the system are evaluated using a precise robotic platform. It is found that the root-mean-squared tracking accuracy is within 5.3 mm for both the esophagus and trachea intubation pathways. Experiments were also designed and performed to demonstrate that the system is capable of tracking the NG tube accurately in biological environments even in presence of stationary ferromagnetic objects (such as clinical instruments). With minimal physical modification to the NG tube and clinical process, this system allows accurate and efficient localization and confirmation of correct NG tube placement without supplemental radiographic methods which is considered the current clinical standard.

Use of an Electromagnetic Device Compared With Chest X-ray to Confirm Nasogastric Feeding Tube Position in Critical Care

BACKGROUND

Insertion of nasogastric feeding tubes (NGTs) is common in critical care. However, misplacement is frequent and can carry a significant morbidity. Current methods to confirm position of NGTs are not reliable in this setting. We retrospectively compared the position of NGTs using an electromagnetically guided nasogastric tube (e-NGT) with that demonstrated by chest x-ray (CXR), the proportion of lung placements avoided, and the time taken to establish enteral feeding.

METHODS

This was a retrospective, observational study undertaken in a tertiary referral, adult intensive care unit between February 2006 and November 2013. Patients were included if they had a radiologically confirmed NGT. All CXRs were independently reviewed by an intensivist to determine position, and a subset of patients had their e-NGT image independently reviewed for quality control. Statistical analysis was in the form of sensitivity and specificity and descriptive where indicated.

RESULTS

In total, 121 NGT placements in 113 patients were analyzed. We found a sensitivity of 98% (95% confidence interval [CI], 93.9%-99.7%) and a specificity of 100% (95% CI, 48.0%-100.0%) when using the e-NGT compared with CXR. In the subset of 51 independently reviewed e-NGT images, 9 lung placements were avoided. The mean (SD) time from e-NGT placement to CXR was 185 (264.4) minutes and to feeding was 404 (77.8) minutes.

CONCLUSION

When placed by a dedicated team, e-NGT allowed immediate detection of tube misplacement. As such, if used as the sole method for determining NGT position, e-NGTs minimize feeding delay and the need for multiple CXRs with subsequent cost savings.

Capnography: An Accurate Method to Assess the Position of the Feeding Tube in a Porcine Model

Objective

To test the accuracy of capnography in the differential placement of feeding tubes into the trachea versus the oesophagus.

Method

Nineteen pigs were anesthetised, and feeding tubes were placed into their tracheas and oesophagi. A naïve examiner attached a capnography to the tube and evaluated the presence or absence of flow waveforms on the capnography. In the next step experiment, we gave 20 intentional oesophageal ventilations to the animals to create a distended stomach. The feeding tubes were reinserted, and examined by a naïve examiner by capnography.

Results

Capnography demonstrated continuous flow waveforms for the feeding tubes placed in the tracheas, but no waveforms were observed for those placed in the oesophagi. In the next step experiment, we found the same results.

Conclusion

Capnography can be used to accurately determine the placement of tracheal versus oesophageal feeding tubes based on the presence or absence of flow waveforms.

Feeding tube placement: errors and complications

Feeding tube placement for enteral nutrition (EN) support is widely used in both critically ill and stable chronically ill patients who are unable to meet their nutrition needs orally. Nasal or oral feeding tubes can be performed blindly at the bedside or with fluoroscopic or endoscopic guidance into the stomach or small bowel. Percutaneous feeding tubes are used when EN support is required for longer periods (>4-6 weeks) and are most commonly placed endoscopically or radiographically. Although generally safe and effective, there is a wide spectrum of known complications associated with feeding tube placement. Errors made at the time of feeding tube placement can result in a number of these procedural and postprocedural complications. In many cases, a single error at the time of placement can result in numerous complications. A thorough knowledge of these errors and avoiding them in practice will decrease iatrogenic complications in a vulnerable population. In addition, early recognition and management of complications will further minimize morbidity and even mortality in enteral feeding tube placement. This article reviews the common errors leading to complications of enteral feeding tube placement and their prevention and management.

Dietitians and small bowel feeding tube placement

Some advanced practice nutrition support dietitians have added small bowel feeding tube placement to their scope of responsibility. This is due, in part, to the challenges of gaining early enteral access in patients with functioning GI tracts. Emerging literature supports the practice of skilled practitioners placing feeding tubes at bedside. A variety of methods can be used to place tubes at the bedside. The nutrition support dietitian must understand licensure and liability considerations to perform this invasive procedure. This article will review literature reports of dietitians placing feeding tubes and provide information on the methods used, training and competencies required, and legal issues involved.

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.

A review of the nursing care of enteral feeding tubes in critically ill adults: part II

Enteral tubes are frequently used in critically ill patients for feeding and gastric decompression. Many of the nursing guidelines to facilitate the care of patients with enteral tubes have not been based on current research, but on ritual and opinion. Using a computerised literature search and an evidence-based classification system as described by the Joanna Briggs Institute for Evidence Based Nursing and Midwifery (JBI), a comprehensive review was undertaken of enteral tube management. Several nursing practices related to enteral tube management are described. Evidence to support alternate methods of tube placement assessment other than abdominal X-ray was inconclusive. Enteral feeding should continue if gastric residual volumes are not considered excessive, as feeding is often withheld unnecessarily. Frequency of checking gastric residual volumes is largely opinion based and varies considerably, but prokinetics that aid gastric emptying should be used if absorption of feeds is problematic. Other recommendations include continuous rather than intermittent feeding, semi-recumbent positioning to reduce the risk of airway aspiration and diligent artificial airway cuff management. Contamination of feeds can be minimised by minimal, meticulous handling and the use of closed rather than open systems. Generally, there was little high quality evidence to support practice recommendations leaving significant scope for further research by nurses in the management of patients with enteral tubes.