Stephen J Taylor

Confirming nasogastric feeding tube position versus the need to feed

OBJECTIVE To review current methods for confirming nasogastric tube position and their efficacy in relation to the need to feed. DESIGN AND METHODS This paper reviews current guidelines and techniques to safely confirm tube position balanced against the need to provide nutrition quickly. All new information was incorporated from electronic database searches up to 7.4.2012. FINDINGS Tube misplacement per se, feeding through undetected misplaced tubes and the potentially fatal complications that arise from both appear to be underestimated. Misplacement occurs due to failure to confirm tube position, lack of expertise in interpretation or inability of the confirmation method to differentiate safe placement from misplacement. Inability to confirm tube position is a major cause of delay to feeding and risks malnutrition. DISCUSSION Theoretically, X-ray is the gold standard for confirming tube position. However, because X-ray is associated with misinterpretation and delays feeding, it should in most cases be the second-line confirmation technique after other methods fail. Currently, pH offers the most practical first-line confirmation method with a threshold of ≤5.0 indicating gastric position. A pH threshold ≤4.0 increases false negatives, excess X-ray use and misinterpretation and delay to feeding whereas a threshold >5.0 can fail to detect lung, oesophageal or intestinal placement. Traumatic injury on misplacement can be pre-empted by use of capnography/capnometry or X-ray at a 35 cm tube depth or an electromagnetic (EM) trace. The EM trace guides real-time placement and re-positioning until gastric position is attained but a larger evidence-base is required to confirm this potential. CONCLUSIONS AND RECOMMENDATIONS Research is urgently required on how to avoid tube misplacement. This must be balanced against risk of delayed feeding and cumulative nutritional deficit leading to subsequent complications and mortality.

Treating Delayed Gastric Emptying in Critical Illness Metoclopramide, Erythromycin, and Bedside (Cortrak) Nasointestinal Tube Placement

BACKGROUND We describe experience using the Cortrak nasointestinal feeding tube and prokinetics in critically ill patients with delayed gastric emptying. METHODS Patient cohorts fed via a Cortrak electromagnetically guided nasointestinal tube (EGNT) or 14 French-gauge nasogastric tube plus prokinetics were retrospectively compared. RESULTS Of 69 EGNT placements in 62 patients, 87% reached the small intestine. The median percentage of the enteral nutrition goal increased from 19% pre-EGNT to 80%-100% between days 1 and 10 post-insertion and was greater than in 58 patients prescribed metoclopramide (40%-87%: days 1-2, 5-7, P < or = .018) or 38 patients prescribed erythromycin (48%-98%; days 1 and 5, P < .0084). Up to day 10, the cumulative feeding days lost were lower for EGNT (1.06) than for metoclopramide (2.6, P < .02) or erythromycin (3.1, P < .02). The EGNT group had a lower use of prokinetics and lower treatment cost. CONCLUSION Most bedside EGNT placements succeed and, compared to nasogastric feeding plus prokinetics, increase enteral nutrition delivery and reduce both cumulative feeding days lost and prokinetic use.

Microendoscopic nasointestinal feeding tube placement in mechanically ventilated patients with gastroparesis.

Gastroparesis often precludes gastric enteral nutrition (EN) in critically ill patients. Our aim was to determine the feasibility of bedside microendoscopic placement of nasointestinal feeding tubes to facilitate enteral nutrition in critically ill patients with poor gastric emptying. Nine mechanically ventilated patients with proven gastroparesis underwent 10 nasointestinal intubations using a microendoscope. These were compared with 35 patients who underwent pH sensor-guided intubation. Blind pH-guided intubation was faster than microendoscopic placement (21.4 ± 10.7 v 32 ± 11.6 min, P = 0.016) and cheaper in terms of disposables [£87 (

Nasogastric tube depth: the ‘NEX’ guideline is incorrect

132) vs £222 (

The efficacy of feeding tubes: confirmation and loss

337) per intubation, P < 0.0001]. Depth of placement (postpyloric: 64% vs 50% including 32% vs 50% reaching duodenum part 3, 4, or jejunum, both NS) was similar. We conclude that microendoscopy failed to improve transpyloric intubation due to poor visualization of gastrointestinal anatomy and difficulty maneuvering the tube–endoscope ensemble. However, when successful, transpyloric placement was always deep, permitting immediate and full EN. To date, the technique and equipment is not superior to pH-guided placement and is not suitable for use by personnel with minimal training.

Does the 5.5 threshold for pH sticks leave a safe margin for error

Misplacing 17-23% of nasogastric (NG) tubes above the stomach ( Rollins et al, 2012 ; Rayner, 2013 ) represents a serious risk in terms of aspiration, further invasive (tube) procedures, irradiation from failed X-ray confirmation, delay to feed and medication. One causal factor is that in the National Patient Safety Agency (NPSA) guidance to place a tube, length is measured from nose to ear to xiphisternum (NEX) ( NSPA, 2011 ); NEX is incorrect because it only approximates the nose to gastro-oesophageal junction (GOJ) distance and is therefore too short. To overcome this and because the xiphisternum is more difficult to locate, local policy is to measure in the opposite direction; xiphisternum to ear to nose (XEN), then add 10 cm. The authors determined whether external body measurements can be used to estimate the NG tube length to safely reach the gastric body. This involved testing the statistical association of body length, age, sex and XEN in consecutive critically ill patients against internal anatomical landmarks determined from an electromagnetic (EM) trace of the tube path. XEN averaged 50 cm in 71 critically ill patients aged 53±20 years. Tube marking and the EM trace were used to determine mean insertion distances at pre-gastro-oesophageal junction (GOJ) (48 cm), where the tube first turns left towards the stomach and becomes shallow on the trace; gastric body (62 cm), where the tube reaches the left-most part of the stomach; and gastric antrum (73 cm) at the midline on the EM trace. Using body length, age, sex and XEN in a linear regression model, only 25% of variability was predicted, showing that external measurements cannot reliably predict the length of tube required to reach the stomach. A tube length of XEN (or NEX) is too short to guarantee gastric placement and is unsafe. XEN+10 cm or more complex measurements will reach the gastric body (mid-stomach) in most patients, but because of wide variation, external measurements often fail to predict a safe distance. Only the EM trace or possibly direct vision can show in real time whether the tip has safely reached the gastric body.

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

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.

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

Rowan Clemente, Specialised Dietitian, and Stephen Taylor, Research Dietitian, North Bristol NHS Trust, consider the current UK pH stick threshold and whether it might be putting vulnerable patients at risk

Undetected oesophageal perforation and feeding-tube misplacement

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.

Confirming nasogastric tube position with electromagnetic tracking versus pH or X-ray and tube radio-opacity

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.