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.

Reproducible image-based profiling with Pycytominer.

Technological advances in high-throughput microscopy have facilitated the acquisition of cell images at a rapid pace, and data pipelines can now extract and process thousands of image-based features from microscopy images. These features represent valuable single-cell phenotypes that contain information about cell state and biological processes. The use of these features for biological discovery is known as image-based or morphological profiling. However, these raw features need processing before use and image-based profiling lacks scalable and reproducible open-source software. Inconsistent processing across studies makes it difficult to compare datasets and processing steps, further delaying the development of optimal pipelines, methods, and analyses. To address these issues, we present Pycytominer, an open-source software package with a vibrant community that establishes an image-based profiling standard. Pycytominer has a simple, user-friendly Application Programming Interface (API) that implements image-based profiling functions for processing high-dimensional morphological features extracted from microscopy images of cells. Establishing Pycytominer as a standard image-based profiling toolkit ensures consistent data processing pipelines with data provenance, therefore minimizing potential inconsistencies and enabling researchers to confidently derive accurate conclusions and discover novel insights from their data, thus driving progress in our field.

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.

Nasointestinal tube placement: Techniques that increase success.

Background: Delayed gastric emptying (DGE) is a major cause of undernutrition that can be overcome using nasointestinal (NI) feeding, but tube placement often fails. We analyse which techniques enable successful NI tube placement. Methods: Efficacy of tube technique was determined at each of six anatomical points: Nose, nasopharynx-oesophagus, stomach-upper and -lower, duodenum part-1 and intestine. Results: In 913 first NI tube placements, significant associations with tube advancement were found in the pharynx (head tilt, jaw thrust, laryngoscopy), stomach_upper (air insufflation, 10 cm or 20-30 cm flexible tube tip ± reverse Seldinger manoeuvre), stomach_lower (air insufflation, possibly flexible tip and wire stiffener) and duodenum part-1 and beyond part-2 (flexible tip and combinations of micro-advance, slack removal, wire stiffener or prokinetic drugs). Conclusion: This is the first study to show what techniques are associated with tube advancement and the alimentary tract level they are specific to.

Intrapulmonary Feeding Tube Placements While Using an Electromagnetic Placement Device: A Review (2019-2021).

BACKGROUND: Intrapulmonary placements of feeding tubes inserted with use of an electromagnetic placement device (EMPD) continue to occur. OBJECTIVE: To describe circumstances and outcomes associated with intrapulmonary feeding tube placements during use of an EMPD. METHODS: A retrospective review of reports to the US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database of intrapulmonary feeding tube placements during use of an EMPD from 2019 through 2021. Complications, outcomes, operator training, interference from anatomical variations and medical devices, and the use and accuracy of radiographs in identifying pulmonary placements were recorded. RESULTS: Sixty-two cases of intrapulmonary tube placement were identified; 10 were associated with a fatal outcome. Pneumothorax occurred in 35 cases and feedings were delivered into the lung in 11 cases. User error was cited in 6 cases and was implicit in most others. Little information was provided about operator training. Four intrapulmonary placements were associated with anatomical variations and 1 with a left ventricular assist device. Radiographic follow-up was described in 28 cases and correctly identified 23 of the intrapulmonary placements. CONCLUSIONS: User error was a significant factor, which highlights the need for empirical data to clarify the amount of training needed to safely credential EMPD operators. Clearer information is needed about anatomical variations that may contraindicate use of an EMPD, as well as medical devices that may interfere with an EMPD. Use of follow-up radiographs, interpreted by qualified personnel, is supported to increase the probability of identifying intrapulmonary tube placements.

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.

Tube placement using 'IRIS': A pilot assessment of its utility and safety.

INTRODUCTION: Most critically ill patients have a feeding tube placed blindly, but 0.5% result in a major lung complication because misplacement is only detected at the end of procedure. Real-time guided tube placement may pre-empt such complications. This clinical effectiveness study examined the ability to visualise anatomy using Kangaroo™ feeding tubes with IRIS technology ('IRIS' tube). METHODS: In a single centre, gastric or intestinal integrated real-time imaging system (IRIS) tubes were prospectively placed in critically ill patients noting the anatomical visualisation. RESULTS: Of 15 placements, 13 were successful gastric placements and used for feeding but one gastric and one intestinal placement failed because of signal loss and inability to find the pylorus, respectively; both tubes were removed. Air insufflation and fluid aspiration were possible with all tubes. Respiratory misplacement was clearly differentiated, prior to reaching the main carina, from gastrointestinal (GI) anatomical markers, permitting removal before causing trauma. Furthermore, non-traumatic placement was visualised in high-risk cases including during advancement through a nostril with a base of skull fracture and into a stomach with a recently haemorrhaging gastric polyp. Individually assessed, direct vision may offer greater safety. X-ray or pH of aspirated fluid confirmed the position of GI tube placements. One adverse event occurred during placement, reversible bradycardia, in a patient previously having bradycardia. Vision was intermittently obscured by bile, mucus or impaction with mucosa. CONCLUSION: 'IRIS' tubes offer real-time guidance regarding anatomical position. Larger studies are needed to establish the best techniques of deploying this equipment and over-coming the difficulties observed.

Cortrak feeding tube placement: interpretation agreement of the 'GI flexure' system versus X-ray.

BACKGROUND: Blind (unguided) feeding tube placement results in 0.5% of patients suffering major complications mainly due to lung misplacement detected prior to feeding. Electromagnet-guided (Cortrak) tube placement could pre-empt such complications but undetected misplacements still occur due to incorrect trace interpretation. By identifying gastrointestinal (GI) flexures from the trace, 'the GI flexure system', it has been proposed that tube position can be interpreted. AIMS: To audit agreement between standards of interpreting tube position: the Cortrak 'GI flexure' system versus X-ray. METHODS: In 185 primary nasointestinal tube placements tube position determined by Cortrak trace interpretation (GI flexure) was retrospectively compared with radiological position in a blinded study. FINDINGS: Radiological and Cortrak interpretation agreed in 92.2-98.3% of placements at different GI flexures. Discrepancy mainly occurred because some radiological images were unclear or did not cover all anatomical points. CONCLUSION: The GI flexure method of Cortrak interpretation appears safe but would necessitate prospective radiological investigation to definitively test equivalence.

Methods of Estimating Nasogastric Tube Length: All, Including "NEX," Are Unsafe.

BACKGROUND: Predominance of blind feeding tube placement makes esophageal tube misplacement and aspiration risk commonplace. Accurate estimation of nose-to-stomach length could reduce this risk. Standards for estimating this length were audited against the length measured from guided tube placement. METHODS: This prospective, single-center observational study used electromagnet-guided tube placement to measure the length from nose to gastric body flexure as part of routine care. This measurement was used to audit standard equations used to estimate this length from external measures: xiphisternum-ear-nose + 10 cm (XEN+10), nose-ear-xiphisternum (NEX), and Hanson_A and Hanson_B. RESULTS: From April 23, 2015, to March 2, 2020, measurements were obtained from 200 primary tube placements. Median length to the gastric body flexure (61 cm) was significantly different from that to the pre-gastroesophageal junction flexure (48 cm) or lengths predicted by NEX (51 cm) or Hanson_A (50.5 cm) and Hanson_B (56.1 cm) (all P < .00001) but similar to XEN+10 (61 cm). Esophageal placement was a potential risk for all methods (NEX: 96.3%, Hanson_A: 99.5%, Hanson_B: 86.9%, XEN+10: 43.2%) and a definite risk for most (NEX and Hanson_A: 14.9%, Hanson_B: 1%, XEN+10: 0%). CONCLUSIONS: NEX and Hanson methods of predicting the length from nose to gastric body flexure are too short and risk esophageal misplacement. XEN+10 reduces but does not eliminate this risk. External measurement predictions are clinically unsafe as a guide blind tube placement. Guided placement is recommended.

Undetected Cortrak tube misplacements in the United Kingdom 2010-17: An audit of trace interpretation.

OBJECTIVES: Determine why Cortrak-guided, undetected tube misplacement may occur in relation to the system of trace interpretation used. METHODOLOGY: From 2010 to 2017 we obtained seven of the eight Cortrak traces from the United Kingdom where misplacement was undetected and the patient received feed. Seven suffered serious harm. Each misplacement was interpreted by three systems: screen position, manufacturer guidance and gastrointestinal (GI) flexures. SETTING: National and local records. MAIN OUTCOME MEASURES: Ability to identify misplacement. RESULTS: Traces that were later identified as misplacements, could not be differentiated from GI position when they wholly or partially: a) overlapped with the GI screen area plotted from historical records (57-71%) or b) met both manufacturer guidance criteria or were confused with receiver misplacement or unusual anatomy and reached the lower left quadrant (14-71%). Conversely, all lung misplacements were identified as unsafe using the GI flexure system. All three systems failed to detect the intra-peritoneal trace. Traces were inconsistently stored by healthcare centres. CONCLUSION: Trace file storage should be mandated by and accessible to relevant health authorisation bodies to improve safety research. Screen position alone and manufacturer guidance fail to consistently differentiate the shape of safe from unsafe traces. GI flexure interpretation appears safer but requires testing in larger studies.

Feeding tube securement in critical illness: implications for safety.

Over 50 % of tape-secured feeding tubes are inadvertently lost. The impact of nasal bridle securement on nasogastric (NG) and nasointestinal (NI) tube loss, outcome and duration of use was determined from 1 October 2014 (NG) and 1 January 2010 respectively to 31 December 2017. From this and published data, the potential impact of nasal bridles on major complications was determined. Use of nasal bridles was independently associated with: an 80% reduction in inadvertent NI tube loss (odds ratio (OR): 95% confidence interval (CI): 0.2: 0.12-0.33, p<0.0001); increased duration of tube use (2.2 days, 95% CI: 0.7-3.7, p= 0.004); and an almost threefold likelihood of tubes being used until no longer needed (OR: 2.8, 95%CI: 1.9-4.3, p<0.0001). In a single-room intensive care unit, inadvertent tube loss dropped from 53% to 9% and tube redundancy (tube no longer required) rose from 20% to 64%. UK-wide bridle securement, by reducing premature tube loss and the need for replacement by 40%, could be associated with 1422 fewer pneumonias or pneumothoraces and 768 fewer deaths.

Cortrak tube placement part 2: guidance to avoid misplacement is inadequate.

Electromagnetic (EM)-guided tube placement has been successfully used to pre-empt lung misplacement, but undetected misplacements continue to occur. The authors conducted an audit to investigate whether official Cortrak or local guidance enabled differentiation of gastrointestinal (GI) from lung traces. X-ray, pH or an EM trace beyond the gastric body were used to independently confirm gastric position. The authors undertook 596 nasointestinal (NI) tube placements, of which 361 were primary GI placements and 41 lung misplacements. Official guidance that in GI traces a midline deviation is absent cannot differentiate GI from lung traces because deviation is common in both. However, when comparing a trace in the same patient, midline deviation during lung misplacement always occurred >18 cm above the horizontal line compared with only 33% of the subsequent GI deviation (p<0.0001). Official guidance could lead to aborted GI placements or undetected lung placements. EM-guided placement must have an expert-led understanding of the 3D trace pattern, artefact correction and appraised practical experience differentiating GI from lung placement. The authors invite Halyard Health to update guidance in view of these findings.

Cortrak tube placement part 1: confirming by quadrant may be unsafe.

Gastric confirmation by pH is only achievable in approximately 50% of placements and X-rays are expensive and may be misinterpreted. Bedside electromagnetic (EM) guidance offers real-time confirmation. The authors determined the accuracy of guidance in predicting gastric body position from the EM trace using official Cortrak guidance (the EM trace reaches the bottom left quadrant of the anterior screen) compared with local guidance (detailed anterior-depth description of the GI flexures). X-ray, pH or an EM trace beyond the gastric body were used to independently confirm gastric position. Of 496 EM traces, 49% of tubes were in the oesophagus on entry to the lower left quadrant whereas 12% had already reached the gastric body in the upper left quadrant. Overall, predicting position by quadrant was 70% accurate whereas differentiating the pre-gastro-oesophageal junction (pre-GOJ) from the gastric body flexure was 100% accurate. Confirming gastric position by the anterior trace quadrant appears to be unsafe whereas expert differentiation of the pre-GOJ and gastric body flexures was reliable. The authors invite Corpak Medsystems (now owned by Halyard Health) to update its guidance in view of these findings.

Stroke: ineffective tube securement reduces nutrition and drug treatment.

Stroke patients with dysphagia often depend on nutrition, hydration and medication via nasogastric (NG) feeding tubes. Securing tubes using tape is associated with repeated tube loss. In this study, the authors determined cause and effect by auditing tube placement methods, delays incurred, duration and costs. Of 202 NG tube placements in 75 patients, 67 placements occurred in 17 patients over a full course of enteral nutrition (EN) and 40 of these placements were tracked. Tubes were secured by tape in 100%, mittens 31% and special observation 5.4%. However, over an EN course, inadvertent tube loss occurred in 82% of patients and was associated with age (p=0.049) and mitten use (p<0.001): 64% of tubes were lost due to patients and 9% slipped. Average 'tube life' was 2 days, less than 25% of the EN episode (p<0.001). While tube placement occurred within 2.55 hours of request, X-ray confirmation led to a delay in feed and drugs of 8-9 hours per tube placement and loss of 18.8% of feeding time per EN episode. Delays exceeded the 1-hour and 4-hour limits for antibiotics and other medicines in 20% and 80%, respectively. In the 17 tracked patients, it was estimated that 55% of the £5979 direct costs could be saved by nasal bridle use. In conclusion, most tubes studied were lost to inadvertent tube removal, leading to clinically significant delays to nutrition, hydration and drug treatments; this may impair recovery. Reducing tube loss is likely to reduce patient distress, treatment cost and enhance recovery.

Sensewheel: an adjunct to wheelchair skills training.

The purpose of this Letter was to investigate the influence of real-time verbal feedback to optimise push arc during over ground manual wheelchair propulsion. Ten healthy non-wheelchair users pushed a manual wheelchair for a distance of 25 m on level paving, initially with no feedback and then with real-time verbal feedback aimed at controlling push arc within a range of 85°-100°. The real-time feedback was provided by a physiotherapist walking behind the wheelchair, viewing real-time data on a tablet personal computer received from the Sensewheel, a lightweight instrumented wheelchair wheel. The real-time verbal feedback enabled the participants to significantly increase their push arc. This increase in push arc resulted in a non-significant reduction in push rate and a significant increase in peak force application. The intervention enabled participants to complete the task at a higher mean velocity using significantly fewer pushes. This was achieved via a significant increase in the power generated during the push phase. This Letter identifies that a lightweight instrumented wheelchair wheel such as the Sensewheel is a useful adjunct to wheelchair skills training. Targeting the optimisation of push arc resulted in beneficial changes in propulsion technique.

A randomised controlled feasibility and proof-of-concept trial in delayed gastric emptying when metoclopramide fails: We should revisit nasointestinal feeding versus dual prokinetic treatment: Achieving goal nutrition in critical illness and delayed gastric emptying: Trial of nasointestinal feeding versus nasogastric feeding plus prokinetics.

BACKGROUND & AIMS: Delayed gastric emptying (DGE) commonly limits the use of enteral nutrition (EN) and may increase ventilator-associated pneumonia. Nasointestinal feeding has not been tested against dual prokinetic treatment (Metoclopramide and Erythromycin) in DGE refractory to metoclopramide. This trial tests the feasibility of recruiting this 'treatment-failed' population and the proof of concept that nasointestinal (NI) feeding can increase the amount of feed tolerated (% goal) when compared to nasogastric (NG) feeding plus metoclopramide and erythromycin treatment. METHODS: Eligible patients were those who were mechanically ventilated and over 20 years old, with delayed gastric emptying (DGE), defined as a gastric residual volume ≥250 ml or vomiting, and who failed to respond to first-line prokinetic treatment of 3 doses of 10 mg IV metoclopramide over 24 h. When assent was obtained, patients were randomised to receive immediate nasointestinal tube placement and feeding or nasogastric feeding plus metoclopramide and erythromycin (prokinetic) treatment. RESULTS: Of 208 patients with DGE, 77 were eligible, 2 refused assent, 25 had contraindications to intervention, almost exclusively prokinetic treatment, and it was feasible to recruit 50. Compared to patients receiving prokinetics (n = 25) those randomised to nasointestinal feeding (n = 25) tolerated more of their feed goal over 5 days (87-95% vs 50-89%) and had a greater area under the curve (median [IQR] 432 [253-464]% vs 350 [213-381]%, p = 0.026) demonstrating proof of concept. However, nasointestinally fed patients also had a larger gastric loss (not feed) associated with the NI route but not with the fluid volume or energy delivered. CONCLUSIONS: This is first study showing that in DGE refractory to metoclopramide NI feeding can increase the feed goal tolerated when compared to dual prokinetic treatment. Future studies should investigate the effect on clinical outcomes. EU CLINICAL TRIALS REGISTER: EudraCT number: 2012-001374-29.

The efficacy of feeding tubes: confirmation and loss.

Around 5% of hospital patients require enteral tube feeding, yet its efficacy and costs are poorly understood. The authors examined radio-opacity, reason for repeat X-ray and overall cost in consecutive patients having tubes confirmed by X-ray when using polyvinylchloride (PVC) Ryles tubes versus CORFLO® (CORTRAK Medsystems) polyurethane tubes (PUTs); and confirmation method and reason for tube loss over an enteral episode. Despite higher PUT cost, because more Ryles tubes required re-X-ray ± radio-contrast injection (0% compared with 26%, p=0.029), overall cost was almost identical (Corflo: £54.2 vs Ryles: £54.6). Confirmation of tube position by X-ray remains more common than pH (51% compared with 45%) and tube loss is mostly as a result of inadvertent patient removal (54%). These studies show that: a) when using X-ray confirmation, PUTs and PVC Ryles tube cost is similar; b) despite pH being taught as first-line confirmation, X-ray remains the most common method therefore PUT use may further reduce cost when staff and outcome costs are included. In addition, more reliable and repeatable bedside confirmation methods are required; c) most tube loss is potentially preventable by use of nasal bridles. Larger studies are required to establish baseline data on problems and cost-effectiveness of enteral tube feeding before intervention trials.