Cortrak feeding tube safety: Criteria for interpreting lung misplacement

BACKGROUND

Pneumothorax occurs in 0.52% of blind tube placements, with 97% occurring in-procedure. Post-procedure pH or x-ray checks cannot prevent these, but CO2 checks or guided tube placement can. Cortrak guided tube placement is widespread, but manufacturer guidance to interpret lung placement is subjective.

AIM

Develop objective criteria to differentiate lung from oesophageal tube placement from measurements and patterns in Cortrak traces.

STUDY DESIGN

Paired comparison of lung and oesophageal Cortrak traces using a retrospective analysis of prospectively collected data in critically ill patients.

RESULTS

From 126 paired traces, lung position, versus oesophageal, was indicated by deviation from the sagittal midline further from the receiver and by a greater angle and distance. No lung trace moved deep to shallow and returned to the midline then turned left compared with 99.2% of oesophageal traces; 56.3% of traces had some degree of artefact caused by receiver misalignment and required interpretation to account for this.

CONCLUSIONS

Differences in trace measurements give early warning of lung placement, and absence of an oesophageal pattern is definitive. Manufacturer guidance describing Cortrak trace is subjective, lacking advice on how to interpret or correct for artefacts. This could fail to prompt a 'lung warning' and/or lead to unnecessary withdrawal of oesophageal placements; both risk trauma.

RELEVANCE TO CLINICAL PRACTICE

The objective criteria developed enable detection of lung placement. If regulatory authorities mandate their use in independently accredited training, Cortrak would be a safe method to confirm tube position.

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.

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.

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.

The feasibility of electromagnetic sensing aided post pyloric feeding tube placement (CORTRAK) in patients with thrombocytopenia with or without anticoagulation on the intensive care unit

BACKGROUND

The successful initiation of enteral nutrition is frequently hampered by various complications occurring in patients treated in the intensive care unit (ICU). Successful placement of a nasojejunal tube by CORTRAK enteral access system (CEAS) has been reported to be a simple bedside tool for placing the postpyloric (PP) feeding tube.

METHODS

We evaluated the efficacy and side effects using CEAS to establish EN in patients with critical illness, thrombocytopenia, and/or anticoagulation.

RESULTS

Fifty-six mechanically ventilated patients were analyzed. Twenty-four of them underwent prior hematopoietic stem cell transplantation (SCT). Sixteen patients received extracorporeal membrane oxygenation treatment because of acute respiratory distress syndrome. The median platelet count at PP placement was 26 g/L (range, 4-106 g/L); 16 patients received therapeutic anticoagulation (activated partial thromboplastin time, 50-70 s). CEAS-assisted placement of a PP nasojejunal tube was performed successfully in all patients. The most frequent adverse event was epistaxis in 27 patients (48.2%), which was mostly mild (Common Terminology Criteria for Adverse Events grade 1, n = 21 [77.8%], and grade 2, n = 6). A significant association between a low platelet count and bleeding complications was observed (P < 0.001).

CONCLUSION

Performed by an experienced operator, CEAS is a simple, rapidly available, and effective bedside tool for safely placing PP feeding tubes for EN in patients with thrombocytopenia, even when showing an otherwise-caused coagulopathy in the ICU. Higher-grade bleeding complications were not observed despite their obvious correlation to thrombocytopenia. A prospective study is in preparation.

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

OBJECTIVES

Checking nasogastric (NG) tube position by X-ray is too late to prevent 1.5% of blind tube placements entering the lung and results in delays to feeding and drugs. We audit the safety of the tube position and delay incurred by X-ray.

METHODS

From Radiology reports, we determined whether tube position was safe for feeding, factors associated with an X-ray request and the time delay from X-ray request to that report. For tubes misplaced into the lung, the distance from the carina to tube tip was measured and compared with that from published records of guided tube placement.

RESULTS

From 1 July 2019 to 30 June 2020, 1934 X-rays were done to check NG tube position in 891 patients. Gastric placement was confirmed in 85% but, because of tube proximity to the oesophagus, only 73% were deemed safe to feed. The 2.2% of tubes reported to be in the lung were a median of 18 cm beyond the carina compared to 12 cm and 0 cm for electromagnetic and direct vision methods of guided placement. X-ray checks delayed feed and drug treatment by >2 h in 51% of placements and 33% of patients required >3 X-rays during their enteral episode.

CONCLUSION

X-ray checks are common and detect a high percentage of unsafe tube placements, leading to repeated X-ray and delayed delivery of drugs and nutrition. Interpretation can be difficult even when following standard national criteria and post-placement X-ray cannot prevent deep lung placement. Guided or combined methods of confirming tube placement should be investigated.

ADVANCES IN KNOWLEDGE

Reports included 27.5% of placements as unsafe, 2.2% in the lung at a median depth of 18 cm beyond the carina and too late to prevent 7 pneumothoraces. X-rays were repeated >3 times in 33% of patients over their enteral course and we are associated with clinically significant delays to drug treatment (and nutrition) in 51%; combined methods of tube confirmation or guided placement may be safer and more efficient.

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: accuracy of the 'GI flexure system' versus manufacturer guidance

Electromagnetic (EM) guided enteral tube placement may reduce lung misplacement to almost zero in expert centres, but more than 60 undetected misplacements had occurred by 2016 resulting in major morbidity or death.

AIM

Determine the accuracy of manufacturer guidance in trace interpretation against what is referred to as the 'GI flexure system'.

METHODS

The authors prospectively observed the accuracy of the 'GI flexure system' of trace interpretation against manufacturer guidance in primary nasointestinal (NI) tube placements.

FINDINGS

Contrary to manufacturer guidance, 33% of traces deviated >5 cm from the sagittal midline and 26.5% were oesophageal when entering the lower left quadrant, incorrectly indicating lung and gastric placement, respectively. Conversely, the GI flexure system identified ≥99.4% of GI traces when they reached the gastric body flexure; 100% at the superior duodenal flexure. All lung misplacements were identified by the absence of GI flexures.

CONCLUSION

Current manufacturer guidance should be updated to the GI flexure system of interpretation.

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.

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.

Pneumothoraces Prevented With Use of Electromagnetic Device to Place Feeding Tubes

BACKGROUND

A US Food and Drug Administration safety letter warned about the risk for pneumothoraces during feeding tube insertion despite the use of electromagnetic placement devices that provide real-time visualization of feeding tube position.

OBJECTIVES

To systematically assess pulmonary placement and pneumothoraces in CORTRAK-assisted feeding tube insertions.

METHODS

CINAHL, MEDLINE, and Cochrane databases were searched for studies of CORTRAK-assisted feeding tube insertion. Thirty-two studies documenting pulmonary placement and/or complications of feeding tube insertion were found.

RESULTS

Operators recognized pulmonary placement on insertion tracings during 202 CORTRAK-assisted feeding tube insertion procedures, resulting in the immediate withdrawal of 199 feeding tubes. One pneumothorax was identified later by radiography. Seven pulmonary placements were not recognized by CORTRAK operators at the time of feeding tube insertion, resulting in 2 pneumothoraces. The incidence of pneumothorax for CORTRAK-assisted feeding tube insertions was 0.02% (3 of 17039). Of the feeding tubes inserted into the pulmonary system - either found during or after the procedure -1.4% (3 of 209) resulted in pneumothoraces (as opposed to the 19% to 28% incidence of pneumothorax for blind feeding tube insertions. Operators recognizing pulmonary placement on CORTRAK insertion tracings may have prevented 97% (202 of 209) of feeding tubes from being inserted farther into the respiratory tract.

CONCLUSIONS

Feeding tube insertion with an electromagnetic placement device is advantageous over blind feeding tube insertion because the operator can recognize pulmonary placement early and withdraw the feeding tube, thus decreasing the risk of pulmonary complications.

Feasibility and safety of a novel electromagnetic device for small-bore feeding tube placement

BACKGROUND

Misplacement of enteral feeding tubes (EFT) in the lungs is a serious and potentially fatal event. A recent Food and Drug Administration Patient Safety Alert emphasized the need for improved technology for the safe and effective delivery of EFTs.

OBJECTIVE

We investigated the feasibility and safety of ENvue, a novel electromagnetic tracking system (EMTS) to aid qualified operators in the placement of EFT.

METHODS

This is a prospective, single-arm study of patients in intensive care units at two US hospitals who required EFTs. The primary outcome was appropriate placement of EFTs without occurrence of guidance-related adverse events (AEs), as confirmed by both EMTS and radiography. Secondary outcomes were reconfirmation of the EFT tip location at a follow-up visit using the EMTS compared with radiography, tube retrograde migration from initial location and AEs.

RESULTS

Sixty-five patients were included in the intent-to-treat analysis. EFTs were successfully placed in 57 patients. In eight patients, placement was unsuccessful due to anatomic abnormalities. According to both the EMTS and radiography, no lung placements occurred. No pneumothoraces were reported, nor any guidance-related AEs. Precise agreement of tube tip location was achieved between the EMTS evaluations and radiographs for 56 of the 58 (96.5%) successful placements (one patient had two placements). Tube tip location was re-confirmed 12-49 hours after EFT insertion by the EMTS and radiographs in 48 patients (84%). For 43/48 patients (89.5%), full agreement between the EMTS and radiography evaluations was observed. For the five remaining patients, the misalignment between the evaluations was within the gastrointestinal tract. Retrograde migration from the initial location was observed in 4/49 patients (8%).

CONCLUSION

A novel electromagnetic system demonstrated feasibility and safety of real-time and follow-up tracking of EFT placement into the stomach and small intestine, as confirmed by radiographs. No inadvertent placements into the lungs were documented.

LEVEL OF EVIDENCE

Level V (large case series).

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.

CORTRAK Superuser Competency Assessment and Training Recommendations

BACKGROUND

Blind insertion of feeding tubes remains unsafe. Electromagnetic placement devices such as the CORTRAK Enteral Access System allow operators to interpret placement of feeding tubes in real time. However, pneumothoraces have been reported and inadequate user expertise is a concern.

OBJECTIVE

To explore factors influencing competency of CORTRAK-assisted feeding tube insertion.

METHODS

A prospective, observational pilot study was conducted. Data collection included demographics, self-confidence, clinical judgment regarding CORTRAK-assisted feeding tube insertion, and general self-efficacy. CORTRAK-assisted feeding tube insertions were performed with the Anatomical Box and CORMAN task trainers.

RESULTS

Twenty nurses who had inserted a mean of 53 CORTRAK feeding tubes participated. Participants inserted a mean of 2 CORTRAK feeding tubes weekly; each had inserted a feeding tube in the past 7 days. All superusers were competent; 1 required remediation for improper receiver unit placement. Mean (SD) scores were 35 (3.68) on a 40-point scale for self-efficacy, 4.6 (0.68) on a 5-point scale for self-reported feeding tube insertion confidence, and 4.85 (0.49) on a 5-point scale for demonstrated confidence. Participants estimated that 8 CORTRAK-assisted insertions were needed before they felt competent as super users. Confidence with the CORTRAK tracing was estimated to require 10 feeding tube insertions. Six participants continued to assess placement by auscultation, suggesting low confidence in their interpretation of the tracing.

CONCLUSIONS

At least 3 observations should be performed to assess initial competency; the number should be individualized to the operator. Interpretation of the insertion tracing is complex and requires multiple performance opportunities to gain competency and confidence for this high-risk skill.

Bedside electromagnetic-guided placement of nasoenteral feeding tubes among critically Ill patients: A single-centre randomized controlled trial

PURPOSE

We aimed to compare the effectiveness of EM-guided and endoscopic nasoenteral feeding tube placement among critically ill patients.

MATERIALS AND METHODS

We performed a single-center, randomized controlled trial among 161 adult patients admitted to intensive care units (ICUs) requiring nasoenteral feeding. Patients were randomly assigned to EM-guided or endoscopic nasoenteral feeding tube placement (1:1). The primary end point was the total success rate of correct jejunal placement.

RESULTS

This was achieved in 74/81 and 76/80 patients who underwent EM-guided and endoscopic jejunal tube placements, respectively (91.4% vs. 95%; relative risk, 0.556; [CI], 0.156-1.980; P = 0.360). The EM-guided group had more placement attempts, longer placement time, and shorter inserted nasal intestinal tube length. However, they had shorter total placement procedure duration and physician's order-tube placement and order-start of feeding intervals. The EM-guided group had higher discomfort level and recommendation scores and lesser patient costs. This trial is registered at Chinese Clinical Trials Registry (ChiCTR-IOR-17011737).

CONCLUSION

Bedside EM-guided placement is as fast, safe, and successful as endoscopic placement and may be considered the preferred technique in critically ill patients.

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.