Cortrak feeding tube placement: accuracy of the 'GI flexure system' versus manufacturer guidance

Feeding tube safety: National guidance ignores the 'elephant in the room'

BackgroundNational guidance attempts to prevent tubes remaining undetected and being used when misplaced in the respiratory tract. The 'elephant in the room' is that this guidance detects misplacement too late to prevent most pneumothoraces and pneumonias.ObjectiveReview risks of undetected and detected respiratory or oesophageal tube misplacements and how 'in-procedure' methods of determining tube position might reduce them.MethodsTube misplacement risk was compared for different methods of checking tube position. Data were obtained from UK NHS England (NHSE), a literature search between 1986 and 12/07/2024 using CINAHL, Embase, Medline and Emcare and from a local database.ResultsPost-procedure pH or X-ray checks on tube position have failed to prevent a rising incidence of undetected respiratory misplacements (NEVER events) (0.013%). Worse, current checks cannot prevent the 0.52% of placements that lead to in-procedure pneumothorax, constituting 97% of lung complications. In addition, pH may fail to prevent aspiration risk from oesophageal misplacement. Conversely, pneumothorax-risk would be reduced to 0.021% by using a supplementary mid-procedure CO2 check or to 0.005% with expert guided tube placement (both p < 0.0001). Guided tube placement can additionally pre-empt oesophageal-related complications, but its safety is expert-dependent, with higher rates of undetected misplacement and pneumothorax in low-use Cortrak centres (0.10%) than expert centres (0%, p < 0.009).ConclusionThe high health burden from feeding tube-related complications could be almost eliminated if regulatory authorities recommended a mid-procedure CO2 check for respiratory placement or expert guided tube placement, alongside mandates for the necessary training.

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.

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.

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.

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.

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.