An externally validated guide to anatomical interpretation using a direct-vision ('IRIS') feeding tube

BACKGROUND & AIMS

Most of the 11.5 million feeding tubes placed annually in Europe and the USA are placed 'blind'. This carries a 1.6% risk that these tubes will enter the lung and 0.5% cause pneumothorax or pneumonia regardless of whether misplacement is identified prior to feeding. Tube placement by direct vision may reduce the risk of respiratory or oesophageal misplacement. This study externally validated whether an 'operator guide' would enable novice operators to differentiate the respiratory and alimentary tracts.

METHODS

One IRIS tube was placed in each of 40 patients. Novice operators interpreted anatomical position using the built-in tube camera. Interpretation was checked from recorded images by consultant gastroenterologists and end-of-procedure checks using pH or X-ray checked by Radiologists and a consultant intensivist.

RESULTS

The 40 patients were a median of 68y (IQR: 56-75), 70% male, mostly medical (65%), conscious (67.5%) and 70% had no artificial airway. Three tubes were removed due to failed placement. In the remaining 37 placements, novice operators identified the airway in 17 (45.9%) and airway + respiratory tract in 19 (51.4%), but redirected all these tubes into the oesophagus. By using direct vision to reduce the proportion of tubes near the airway or in respiratory tract from 0.514 to 0, operator discrimination between the respiratory and alimentary tracts was highly significant (0.514 vs 0: p < 0.0001, power >99.9% when significance = 0.05). In addition, organ boundaries (respiratory tract vs oesophagus, oesophagus vs stomach, stomach vs intestine) were identified in 100%.

CONCLUSIONS

Novice operators, trained using the guide, identified all respiratory misplacements and accurately interpreted IRIS tube position. Guide-based training could enable widespread use of direct vision as a means to prevent tube-related complications.

Validation of image interpretation for direct vision-guided feeding tube placement

BACKGROUND

Unguided (blind) tube placement commonly results in lung (1.6%) and oesophageal (5%) misplacement, which can lead to pneumothorax, aspiration pneumonia, death, feeding delays, and increased cost. Use of real-time direct vision may reduce risk. We validated the accuracy of a guide to train new operators in the use of direct vision-guided tube placement.

METHODS

Using direct vision, operators matched anatomy viewed to anatomical markers in a preliminary operator guide. We examined how accurately the guide predicted tube position, specifically whether respiratory and gastrointestinal placement could be differentiated.

RESULTS

A total of 100 patients each had one tube placement. Placement was aborted in 6% because of inability to enter or move beyond the oesophagus. In 15 of 20 placements in which the glottic opening was identified, the tube was maneuvered to avoid entry into the respiratory tract. Of 96 tubes that reached the oesophagus, 17 had entered the trachea; all were withdrawn pre-carina. One or more specific characteristics identified each organ, differentiating the trachea-oesophagus (P < 0.0001), oesophagus-stomach, and stomach-intestine in 100%. End-of-procedure tube position was ascertained by pH ≤4.0 (gastric) of aspirated fluid and/or x-ray (gastric or intestinal). In patients with a trauma risk (13%), it was avoided by identification that the tube remained within the nasal, oesophageal, or gastric lumen.

CONCLUSION

Operators successfully matched anatomy seen by direct vision to images and descriptions of anatomy in the "operator guide." This validated that the operator guide accurately facilitates interpretation of tube position and enabled avoidance of lung trauma and oesophageal misplacement.

Integrated real-time imaging system, 'IRIS', Kangaroo feeding tube: a guide to placement and image interpretation

Background

Lung complications occur in 0.5% of the millions of blind tube placements. This represents a major health burden. Use of a Kangaroo feeding tubes with an ‘integrated real-time imaging system’ (‘IRIS’ tube) may pre-empt such complications. We aimed to produce a preliminary operator guide to IRIS tube placement and interpretation of position.

Methods

In a single centre, IRIS tubes were prospectively placed in intensive care unit patients. Characteristics of tube placement and visualised anatomy were recorded in each organ to produce a guide.

Results

Of 45 patients having one tube placement, 3 were aborted due to refusal (n=1) or inability to enter the oesophagus (n=2). Of 43 tubes placed beyond 30 cm, 12 (28%) initially entered the respiratory tract but all were withdrawn before reaching the main carina. We identified anatomical markers for the nasal or oral cavity (97.8%), respiratory tract (100%), oesophagus (97.6%), stomach (100%) and intestine (100%). Organ differentiation was possible in 100%: trachea-oesophagus, oesophagus-stomach and stomach-intestine. Gastric tube position was confirmed by aspiration of fluid with a pH <4.0 and/ or X-ray. Trauma was avoided in 13.6% by identifying that the tube remained in the nasal lumen in the presence of a base of skull fracture (n=3) and in the stomach in the presence of recently bleeding polyps or mucosa (n=3). A systematic guide was produced from records of tube placement and interpretation of anatomical images.

Conclusion

By permitting real-time confirmation of tube position, direct vision may reduce risk of lung complications. The preliminary operator guide requires validation in larger studies.

Development of a Competency Model for Placement and Verification of Nasogastric and Nasoenteric Feeding Tubes for Adult Hospitalized Patients

Nasogastric/nasoenteric (NG/NE) feeding tube placements are associated with adverse events and, without proper training, can lead to devastating and significant patient harm related to misplacement. Safe feeding tube placement practices and verification are critical. There are many procedures and techniques for placement and verification; this paper provides an overview and update of techniques to guide practitioners in making clinical decisions. Regardless of placement technique and verification practices employed, it is essential that training and competency are maintained and documented for all clinicians placing NG/NE feeding tubes. This paper has been approved by the American Society for Parenteral and Enteral Nutrition (ASPEN) Board of Directors.

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.

Clinical usefulness of capnographic monitoring when inserting a feeding tube in critically ill patients: retrospective cohort study

BACKGROUND

It is not rare for a small-bore feeding tube to be inserted incorrectly into the respiratory system in critically ill patients. Thus, monitoring is necessary to prevent respiratory malplacement of the tube. We investigated the utility of capnographic monitoring to prevent respiratory complications due to feeding tube mispositioning in critically ill patients.

METHODS

This study was a pre and post-interventional study, including 445 feeding tube placements events studied retrospectively in the medical and surgical intensive care units of the Samsung Medical Center. We compared outcomes between time periods before and after capnographic monitoring and documented any respiratory complications.

RESULTS

Feeding tubes were inserted in 275 cases without capnographic monitoring. Capnographic monitoring was performed in 170 cases. Sixteen patients (4%) had respiratory complications of all tube placements. Feeding tube was inserted into the trachea in 11 (2%) patients and for a pneumothorax in five (1%) patients. Fourteen cases of respiratory complications were detected in the control group (14/275, 5%, 10 tracheal insertions and four pneumothoraxes). Two respiratory complications were detected in the capnographic monitoring group (2/170, 1%, one tracheal insertion and one pneumothorax). Respiratory complications were detected less frequently in the capnographic monitoring group than that in the control group (P = 0.035).

CONCLUSIONS

Capnographic monitoring is simple, easy to learn, and may be useful to prevent respiratory complications when placing a feeding tube in a critically ill patient.

ASPEN Safe Practices for Enteral Nutrition Therapy [Formula: see text]

Enteral nutrition (EN) is a valuable clinical intervention for patients of all ages in a variety of care settings. Along with its many outcome benefits come the potential for adverse effects. These safety issues are the result of clinical complications and of process-related errors. The latter can occur at any step from patient assessment, prescribing, and order review, to product selection, labeling, and administration. To maximize the benefits of EN while minimizing adverse events requires that a systematic approach of care be in place. This includes open communication, standardization, and incorporation of best practices into the EN process. This document provides recommendations based on the available evidence and expert consensus for safe practices, across each step of the process, for all those involved in caring for patients receiving EN.

Confirming nasogastric tube placement: Is the colorimeter as sensitive and specific as X-ray? A diagnostic accuracy study

BACKGROUND

The effect of delivering enteral nutrition or medications via a nasogastric tube that is inadvertently located in the tracheobronchial tract can cause respiratory complications. Although radiographic examination is accepted as the gold standard for confirming the position of patients' enteral tubes, it is costly, involves risks of radiation, and is not failsafe. Studies using carbon dioxide sensors to detect inadvertent nasogastric tube placements have been conducted in intensive care settings. However, none involved patients in general wards.

OBJECTIVE

The objective of this study was to ascertain the diagnostic measure of colorimeter, with radiographic examination as the reference standard, to confirm the location of nasogastric tubes in patients.

DESIGN

A prospective observational study of a diagnostic test.

SETTING

This study was conducted in the general wards of an approximately 1100-bed acute care tertiary hospital of an Academic Medical Center in Singapore.

PARTICIPANTS

Adult patients with nasogastric tubes admitted to the general wards were recruited into the study.

METHODS

The colorimeter was attached to the nasogastric tube to detect for the presence of carbon dioxide, suggestive of a tracheobronchial placement. The exact location of the nasogastric tube was subsequently confirmed by a radiographic examination.

RESULTS

A total of 192 tests were undertaken. The colorimeter detected carbon dioxide in 29 tested nasogastric tubes, of which radiographic examination confirmed that four tubes were located in the tracheobronchial tract. The colorimeter failed to detect carbon dioxide in one nasogastric tube that was located in the tracheobronchial tract, thus, demonstrating a sensitivity of 0.80 [95% CI (0.376, 0.964)]. The colorimeter detected absence of carbon dioxide in 163 tested nasogastric tubes in which radiographic examination confirmed 160 gastrointestinal and one tracheobronchial placements, demonstrating a specificity of 0.865 [95% CI (0.808, 0.907)]. The colorimeter detected one tracheobronchial nasogastric tube placement that the radiographic examination was misinterpreted.

CONCLUSION

The study found that the use of the colorimeter in the general ward setting was not 100% sensitive or specific in ascertaining the location of a nasogastric tube as previously reported by many studies undertaken in intensive care settings. This is the first study on the use of a colorimeter to confirm the placement of a nasogastric tube in adult patients in the general ward setting. More research on the use of a colorimeter in the general ward setting and its potential use in certain processes for confirming the placement of a nasogastric tube is warranted.

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.

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.

Blind insertion of feeding tubes in intensive care units: a national survey

BACKGROUND

Although most critically ill patients experience at least 1 blind insertion of a feeding tube during their stay in an intensive care unit, little is known about the types of health care personnel who perform these insertions or about methods used to determine proper positioning of the tubes.

OBJECTIVES

To describe results from a national survey of critical care nurses about feeding tube practices in their adult intensive care units. The questions asked included who performs blind insertions of feeding tubes and what methods are used to determine if the tubes are properly positioned.

METHODS

Data were collected from members of the American Association of Critical-Care Nurses via pencil-and-paper and online surveys. Results from both forms were combined for data analysis and were compared with practice recommendations of national-level organizations.

RESULTS

A total of 2298 responses were obtained. Physicians perform more blind insertions of styleted feeding tubes than do nurses; in contrast, nurses place more nonstyleted tubes. Radiographic confirmation of correct position is mandated more often for blindly inserted styleted tubes (92.3%) than for nonstyleted tubes (57.5%). The 3 most commonly used bedside methods to determine tube location are auscultation for air injected via the tube, appearance of feeding tube aspirate, and observation for indications of respiratory distress.

CONCLUSIONS

Recommendations from multiple national-level organizations to obtain radiographic confirmation that each blindly inserted feeding tube is correctly positioned before the first use of the tube are not adequately implemented. Auscultation is widely used despite recommendations to the contrary.

Case series: Tension pneumothorax complicating narrow-bore enteral feeding tube placement

Frequently, narrow-bore feeding tubes are placed in critically ill hospitalized patients without difficulty. However, due to the simplicity and relative ease of bedside placement of feeding tubes, complications, including life threatening, are often minimized. We report 3 cases of severe pleuropulmonary complications after routine bedside placement of a narrow-bore enteral feeding tubes and a review of the literature. These episodes have not only prompted our adoption of a new policy specifying the routine use of ultrasound to guide feeding tube placement in obtunded or mechanically ventilated patients but also offer recommendations post-removal of misplaced feeding tubes.