X-ray checks of NG tube position: a case for guided tube placement

Comment on Miyamoto et al. Laryngopharyngeal Mucosal Injury Due to Nasogastric Tube Insertion during Cardiopulmonary Resuscitation: A Retrospective Cohort Study. J. Clin. Med. 2024, 13, 261

I read with great interest the study from Miyamoto et al [...].

Effect of modified gastrointestinal decompression under abdominal CT in patients with intestinal obstruction

INTRODUCTION

We aimed to evaluate the effect of continuous quality improvement on modified gastrointestinal decompression under abdominal computed tomography (CT) in patients with intestinal obstruction.

METHODS

The CT images of 74 patients with intestinal obstruction who underwent gastrointestinal decompression in our hospital from 1 January 2018 to 31 December 2019 were analysed retrospectively (Control group). Factors influencing unsatisfactory decompression effects were analysed, and corresponding improvement measures were formulated and implemented. A total of 77 patients from 1 January 2020 to 31 March 2022 were enrolled prospectively (Study group). The position of the nasogastric tube end, the amount of gastric drainage within 24h and the degree of abdominal distension relief were compared before and after the improvement.

RESULTS

After implementation of continuous quality improvement, the proportion of the end of the nasogastric tube reaching the antrum, the amount of gastric fluid drainage within 24h and the degree of abdominal distension relief were better than those before improvement (p<0.001, respectively). The execution rate and accuracy rate of CT interpretations by nurses reached 100% and 82%, respectively.

CONCLUSIONS

Modified gastrointestinal decompression based on abdominal CT scans can increase the success of gastrointestinal decompression and effectively reduce the discomfort of patients.

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.

Mal-positioned nasogastric feeding tubes: are medical students safe to identify them?

OBJECTIVES

Nasogastric tube (NGT) placement is listed against Clinical Imaging in the upcoming Medical Licensing Assessment-compulsory for every graduating UK medical student from 2025. This study aims to establish the ability of medical students to correctly identify the position of an NGT on Chest X-ray (CXR) and to evaluate a learning tool to improve student outcome in this area.

METHODS

Fourth-year (MB4) and fifth-year (MB5) medical students were invited to view 20 CXRs with 14 correctly sited and 6 mal-positioned NGT. MB5 students (Intervention) were exposed to an online interactive learning tool, with MB4 students kept as control. One week later, both groups of students were invited to view 20 more CXRs for NGT placement.

RESULTS

Only 12 (4.8%) of 249 MB5 students and 5 (3.1%) of 161 MB4 students correctly identified all the NGTs on CXRs. The number of students misidentifying 1 or more mal-positioned NGT as "safe to feed" was 129 (51.8%) for MB5 and 76 (47.2%) for MB4 students. This improved significantly (P < .001) following exposure to the learning tool with 58% scoring all CXRs correctly, while 28% scored 1 or more mal-positioned NGT incorrectly. Students struggled to determine if the NGT tip had adequately passed into the stomach. However, they failed to identify an NG tube in the lung ("never event") in just one out of 1,108 opportunities.

CONCLUSION

Medical students' ability to determine if the NGT was in the stomach remains suboptimal despite exposure to over 60 CXRs. Feeding NGT should be formally reported before use.

ADVANCES IN KNOWLEDGE

This is the first attempt at quantifying graduating medical students', and by inference junior doctors', competence in safely identifying misplaced nasogastric feeding tubes. An online, experiential learning resource significantly improved their ability.

Development and clinical feasibility of a reduced-dose radiograph in children for feeding tube placement

BACKGROUND

Temporary feeding tubes are commonly used but may lead to complications if malpositioned. Radiographs are the gold standard for assessing tube position, but clinician concern over radiation risks may curtail their use.

OBJECTIVE

We describe development and use of a reduced dose feeding tube radiograph (RDFTR) targeted for evaluation of feeding tube position.

MATERIALS AND METHODS

Age-based abdominal radiograph was adapted to use the lowest mAs setting of 0.32 mAs with field of view between carina and iliac crests. The protocol was tested in DIGI-13 line-pair plates and anthropomorphic phantoms. Retrospective review of initial clinical use compared dose area product (DAP) for RDFTR and routine abdomen, chest, or infant chest and abdomen. Review of RDFTR reports assessed tube visibility, malpositioning, and incidental critical findings.

RESULTS

Testing through a line-pair phantom showed loss of spatial resolution from 2.2 line pairs to 0.6 line pairs but preserved visibility of feeding tube tip in RDFTR protocol. DAP comparisons across 23,789 exams showed RDFTR reduced median DAP 72-93% compared to abdomen, 55-78% compared to chest, and 76-79% compared to infant chest and abdomen (p<0.001). Review of 3286 reports showed tube was visible in 3256 (99.1%), malpositioned in airway 8 times (0.2%) and in the esophagus 74 times (2.3%). The tip was not visualized in 30 (0.9%). Pneumothorax or pneumoperitoneum was noted seven times (0.2%) but was expected or spurious in five of these cases.

CONCLUSION

RDFTR significantly reduces radiation dose in children with temporary feeding tubes while maintaining visibility of tube tip.

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.

Nasogastric tube insertion length measurement and tip verification in adults: a narrative review

Nasogastric feeding tube insertion is a common but invasive procedure most often blindly placed by nurses in acute and chronic care settings. Although usually not harmful, serious and fatal complications with misplacement still occur and variation in practice still exists. These tubes can be used for drainage or administration of fluids, drugs and/or enteral feeding. During blind insertion, it is important to achieve correct tip position of the tube ideally reaching the body of the stomach. If the insertion length is too short, the tip and/or distal side-openings at the end of the tube can be located in the esophagus increasing the risk of aspiration (pneumonia). Conversely, when the insertion length is too long, the tube might kink in the stomach, curl upwards into the esophagus or enter the duodenum. Studies have demonstrated that the most frequently used technique to determine insertion length (the nose-earlobe-xiphoid method) is too short a distance; new safer methods should be used and further more robust evidence is needed. After blind placement, verifying correct gastric tip positioning is of major importance to avoid serious and sometimes lethal complications.

Performance of Point-of-Care Ultrasonography in Confirming Feeding Tube Placement in Mechanically Ventilated Patients

BACKGROUND

A feeding tube (FT) is routinely placed in critically ill patients, and its correct placement is confirmed with a chest X-ray (CXR), which is considered the gold standard. This study evaluated the diagnostic accuracy of ultrasonography (USG) in verifying FT placement compared to a CXR in an intensive care unit (ICU).

METHOD

This was a prospective single-blind study conducted on patients admitted to the ICU of a tertiary hospital in Malaysia. The FT placements were verified through a fogging test and USG at the neck and subxiphoid points. The results of confirmation of FT placement through USG were compared with those obtained using CXRs.

RESULTS

A total of 80 patients were included in this study. The FT positions were accurately confirmed by overall USG assessments in 71 patients. The percentage of FT placements correctly identified by neck USG was 97.5%, while the percentage of those identified by epigastric USG was 75%. The corresponding patients' CXRs confirmed correct FT placement in 76 patients. The overall USG assessment had a sensitivity of 92.11% and specificity of 75%, a positive predictive value of 98.59%, and a negative predictive value of 33.33%. The USG findings also showed a significant association between FT size and BMI. FTs with a size of 14Fr were better visualized (p = 0.008), and negative USG findings had a significantly higher BMI (p < 0.001).

CONCLUSION

USG is a simple, safe, and reliable bedside assessment that offers relatively high sensitivity in confirming correct FT placement in critically ill patients.

Safety of blind versus guided feeding tube placement: Misplacement and pneumothorax risk

Most intensive care unit patients require a feeding tube, but misplacement risk is high due to the presence of artificial airways and because unconsciousness reduces clinical warnings. Predominantly, tubes are placed 'blindly', where position is not known throughout placement. The result is that 1.6% enter the lung, 0.5% cause pneumothorax and potentially 5% are left in the oesophagus. Guided placement, by identifying tube position in real time, may prevent these problems, but undetected misplacements still occur. We review the safety of guided methods of confirming tube position, including rates of pneumothorax, in the context of current unguided methods. During blind tube placement, tube position can only be tracked intermittently. Excepting X-ray and ultra-sound, most methods of checking position are simple. Conversely, guided tube placement can track tube position from the nose to small intestine (IRIS®), or oesophagus to jejunum (Cortrak™, ENvue®). However, this requires expertise. Overall, guided placement is associated with lower rates of pneumothorax. Unfortunately, for Cortrak, low-use centres have higher rates of undetected misplacement compared with blind placement whereas Cortrak use in high-use centres had lower risk compared with blind placement and low use centres. Because guided placement requires high-level expertise manufacturer training packages have been developed but currently appear insufficient. Specifically, Cortrak's package is less accurate in determining tube position compared to the 'gastrointestinal flexure' system. Validation of an evidence-based guide for IRIS placement is underway. Recommendations are made regarding the training of new operators, including minimum numbers of placements required to achieve expertise.

Considering the role of medical radiation technologists to mitigate the care delivery problems associated with nasogastric tube verification and improve patient care

INTRODUCTION

Misplaced nasogastric (NG) tubes can have deleterious consequences for patients, including death. Medical radiation technologists (MRTs) may be well-positioned to improve the NG tube verification process. The objective of this study was to identify the care delivery problems (CDPs) associated with verifying NG tube placement and to consider where MRTs may mitigate current challenges.

METHODS

This study involved three sources of data; a data audit of NG tube chest x-rays (CXRs), a review of related incident reports, and a staff survey, all conducted in the general radiography departments at two large, affiliated teaching hospitals in Toronto, Ontario.

RESULTS

Over a 36-month period, 9,655 NG tube examinations were performed. Just over half of all exams (55.5%) required a single image for verification, while 10.1% required four or more images. The median time an MRT spent for an NG tube examination was 13.5 minutes, with 45.4% of exams completed in 10 minutes or less, while 4.5% required over 30 minutes. 118 incident reports and 57 survey submissions suggested five key CDPs; delayed verification, lack of verification, incorrect verification, increased radiation exposure, and inefficient workflow.

CONCLUSIONS

CDPs associated with verifying NG tube placement can lead to poor patient care and inefficient workflows. The results of this study suggest that there may be value in future exploration of additional responsibility for MRTs as a potential solution for improving the NG tube process and thus patient care.

Chest X-ray Interpretation: Detecting Devices and Device-Related Complications

This short review has the aim of helping the radiologist to identify medical devices when interpreting a chest X-ray, as well as looking for their most commonly detectable complications. Nowadays, many different medical devices are used, often together, especially in critical patients. It is important for the radiologist to know what to look for and to remember the technical factors that need to be considered when checking each device's positioning.

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.