Evidence Outcome Summary
Synthesis Topic/PICO Question: In hospitalized patients with feeding tubes (nasogastric/orogastric) with initial x-ray verification of placement, does ongoing placement verification prior to feeding/medication administration using pH testing of gastric aspirate as compared to current practice (audible air injection, distal tube length) impact the occurrence of adverse outcomes/events (e.g. delay in feeding/med admin, aspiration, etc.)
| Sources of Evidence
LOE: Quality: |
One sentence summary of what the study is about
Population: Setting: |
List the findings in bullet format | Reason(s) you wouldn’t use this evidence | Author’s conclusions and the bottom line result(s)? | Do the results answer your question?
(Use of pH as on-going confirmation method?)
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Additional comments
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| 1. Perry, A., Kaiser, J., Krueger, K., and the 2022 ENA CPG Committee (2023). Gastric Tube Placement Verification [Clinical practice guideline]. Emergency Nurses Association.
LOE: Level II Quality: High
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ENA CPG, updated from its 2014, 2017 and 2019 version
Lit search 2016-2226, total of 5980 items found, full review 211, 25 included in evidence analysis, 9 as background information |
-The use of auscultation is no longer recommended nor reliable
-Reliability of the use of PH ranges from 84%-97% _Adding lipase increases sensitivity to 97.2% with 100% specificity (no bedside test for lipase currently available) -**PPIs may reduce ability for PH confirmation -In pts over 4 weeks old, PH less than 5 is acceptable, if 5 or greater, XRay is required
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n/a | -XRAY remains the gold standard-
-PH testing when part of a mixed-method confirmation i.e. auscultation, tube marking, PH etc is an acceptable means to confirm NGT/OGT -Ph less than 5 appears to be a reasonable cut off |
yes |
Confirmation accuracy is greater when aspirate and non-aspirate methods used, recommend auscultate, aspirate for pH with visual inspection
There is moderate evidence to support the use of PH testing as a component of a multiple-method bedside verification
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| 2. Northington, et al (2022)
LOE: V Quality: Weak
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Survey completed by 205 nurses in 166 institutions (pediatric) to determine how NG/OG placement is verified: 42% use pH, 24% use Xray | Reporting a combination of radiograph and pH measurement , 88% of pediatric nurses selected evidence-based methods for NGT placement verification placement. | Weak-survey | While progress has been made toward using the EBP methods of pH measurement and/or abdominal x-ray to verify NGT placement, further education is needed to establish this as a standard of care among nursing organizations | no | An EBP standard of care needs to be established |
| 3. Lin (2020)
LOE: Level V (Systematic Review & Meta-Analysis of observational studies) Quality: Moderate
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To evaluate diagnostic performance of methods used to assess gastric tube placement verification in neonates, infants and children. | – 8 studies, 911 participants, evaluated 9 index tests
– pH testing with cutoff values ≤6 for gastric tube position confirmation was the only index test subjected to meta-analysis, with the summary sensitivity and specificity being 0.77 (95% confidence interval [CI] 0.56–0.90) and 0.42 (95% CI 0.16–0.73). – Other methods (color of aspirate, auscultation, carbon dioxide testing, ultrasound, bilirubin, pepsin, trypsin, separately or in combination with the above methods) showed great variations in sensitivities and specificities. |
– 6 out of 8 studies used for meta-analysis showed a high degree of heterogeneity for diagnostic estimates.
– Revealed a moderate summary sensitivity and a low summary specificity for pH cutoffs ≤6. This finding suggests that pH ≤ 6 may not be sufficiently accurate to detect the gastric tube position, which does not support recommendations from multiple guidelines. |
– The conclusion of the inability of pH ≤ 6 for detection of gastric tube position in the studied population can only be drawn with caution because of the heterogeneity of studies.
– Paucity of data and methodological variations in studies make it difficult to arrive at any conclusions regarding the diagnostic test accuracy of pH ≤ 4 or 5 and other index tests in detection of gastric tube placement. – Well-designed studies to strengthen current evidence are recommended. |
Yes/no-paucity of data | The studies included in the meta-analysis had heterogeneity (3 different cutoff values, 2 types of instruments of pH meter and pH paper, different populations of fasting and fed) so the conclusion needs to be considered with caution (p. 658).
pH testing with cutoff values ≤6 for gastric tube position confirmation was the only index test subjected to meta-analysis, with the summary sensitivity and specificity being 0.77 (95% confidence interval [CI] 0.56–0.90) and 0.42 (95% CI 0.16–0.73).
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| 4. Metheny (2019)
LOE: Level V Quality: High
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This is a review of worldwide guidelines for placement verification of NG tubes.
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-All indicate radiographic confirmation as the gold-standard verification of initial placement.
-11 guidelines discuss pH as an adjunct method of placement verification; 9 guidelines discuss specific safe cutoff values; 4 discuss pH ranges between 1 and 4 as safe |
-Wide geographical variety of guidelines advocating for significantly varied methods of confirming placement.
-Unable to confirm primary data of each contributing guideline author |
-Radiographic confirmation of initial placement cannot be replaced by other available methods
-pH safe cutoff not established firmly, wide disagreement among guidelines. |
yes | Helpful as an investigational look into global best-practice
: pH is vetted as a method and ranked highly in terms of safety; does not advise against radiologic confirmation as default. |
| 5. Dias et al., 2019
LOE: IV Quality: High |
Cross-sectional, double-blinded diagnostic test study. Sample: n = 162 neonates, average age 32.92 gestational weeks. | -No relationship between pH values with age or diet. -Aspirate: No relationship between aspirate color and placement -Use of gastric secretion inhibitor drug: pH was higher (>5.5), but only in small sample
-Radiographic placement verification: 98.77% correct placement. -Comparison of pH test and radiographs: 96.25% sensitivity. -Accuracy of pH test with cutoff of 5.5 showed high sensitivity compared to x-ray verification. |
Population | Accuracy of pH test with cutoff of 5.5 showed high sensitivity compared to x-ray verification. | yes | Neonates |
| 6. Irving (2018)
LOE: Level V Quality: High
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Presents the challenges of bedside NG-EAD (Nasogastric-enteral access device) placement and ongoing location verification.
Review the current state of the science for verification of bedside placement of nasogastric tubes and ongoing assessment of tube location in children. |
Abdominal radiograph is the gold standard.
In lieu of or when abdominal x-ray is not available, accurate measurement of enteral tube insertion length, gastric pH testing, and visual observation of gastric aspirate are acceptable non radiologic methods for assessing tube placement.
Specificies children who are high risk (neonates, children with neurological impairment, children in an obtuded state, children who are encephalopathic, have a decreased gag reflex, or are sedated or critically ill) recommends an x-ray. |
Auscultation as a means of verifying NG-EAD placement is discouraged in the literature and is no longer supported by clinical practice organizations.
Yes, speaks to our current practice.
Despite the accuracy of pH and enzyme testing, if NG-EAD placement or location is uncertain, an abdominal radiograph is warranted, as it is accepted as the confirmatory method to verify NGEAD placement. |
X-Ray is goldstandard
pH is reliable method of verifying NG-EAD location in children
radiograph recommended to confirm location when no aspirate is obtained |
Yes (children) | Ph and noting distal tube length are acceptable for placement verification |
| 7. Boullata (2017)
LOE: Level V Quality: High
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Aspen Guidelines | Do not rely on the auscultatory method alone to differentiate between gastric and respiratory placement or between gastric and small bowel placement.”; “Healthcare professionals cannot rely on auscultatory methods to differentiate between gastric and bronchopulmonary tube placement because auscultatory methods cannot distinguish tubes improperly placed in the lung or coiled in the esophagus from properly positioned tubes.”
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Mark the exit site of a feeding tube at the time of the initial placement and document either the incremental marking on the tube or the external length of the tube in the medical record.” [does not give frequency]
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Gastric fluid typically is clear and colorless or grassy green or brown with a pH of 5 or less. Several studies demonstrating the use of pH testing indicate a pH of ≤5.5 from tube aspirate is adequate to check the position of the tube in the stomach.” | Although observing for respiratory symptoms is warranted during EAD insertion, malpositioning may occur without any apparent symptoms.
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| 8. Ni (2017)
LOE: Level IV Quality: Moderate
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Using a decision analytical modelling approach to compare the relative safety of different methods used to verify the placement of NG tubes in the stomach.
Population: 104 cases with documented feeding tube misplacement. Total of 2368 adverse event reports submitted to NRLS (National Reporting and Learning System) Setting: UK |
-UK already follows safety guideline that uses pH testing of NG tube aspirate as a method of initial placement verification followed by chest xrays but US does NOT
-cost analysis not done -only focused on patients with successful aspirations -analysis assumed chest xrays were 100% accurate -excluded pediatric cases |
-before use of tube, using pH test cut-off of 5 is the safest way to verify enteral tube location | Yes-adults | Uses pH as method of initial verification.
Yes, could provide guidance for using pH as a method of ongoing verification. |
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| 9. Clifford (2015)
LOE: Level V (integrative review) Quality: Moderate
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Integrative review and synthesis of literature on the most accurate methods of enteral tube placement and placement verification along with recommendations for practice.
Lit Search bet May-August 2014 (CINAHL, MEDLINE, PubMEd: studies published Jan 2009-June 2014 in English only, limited to 0-18 year old patients). 56 pediatric & adult articles 7 national guidelines dating from 1993-2014 |
-only xray gold standard verification method
PH: -AACN recommends PH 5 or less for ongoing placement verification -feeding/meds can alter gastric pH, but evidence suggests there was no major difference in pH with patients on acid-blocking meds (p. 157) Gastric aspirate appearance: -most helpful to determine stomach vs intestine placement, but use with other methods Tube marking: -marking does not confirm that tube has not moved/coiled so only use in conjunction with other methods Auscultation: -proven unreliable, suggest use of this method be discontinued
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Limitations:
-lack of neonatal evidence -mostly low levels of evidence -outdated evidence (dating from 1993-2014) -UK sources of data included, but they have different practices (e.g. UK uses pH as first-line verification, xray as second-line) |
-place enteral tube via NEMU method
-xray is gold standard but not practical for verification prior to each use of tube -no other verification method on its own is as accurate as xray -consider using combo of 2 or more methods of verification -use analysis of gastric aspirate color and pH along with assessment of tube marking to confirm there has been no migration -algorithm may help as decision making tool with follow up quality improvement studies and data collection |
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| 10. Boeykens (2014)
LOE: Level IV Quality: High
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Prospective observational study to determine the reliability of pH measurement compared to auscultatory method (N 241) | -98.9% accuracy compared to x-ray with pH ≤ 5
-auscultation method elicited 94.2-72.1% accuracy -A pH of ≤ 5.5 aspirate reading is adequate to check the tube placement -Auscultatory method is unreliable |
A point of care testing for pH testing is cumbersome due to many regulatory requirements.
However, with a new testing technology available this method could be used at bedside by clinical nurses |
pH testing is the 2nd best method compared to the gold standard of x-ray method for tube verification.
Rather than using the auscultation method, bedside verification of feeding tube should be based on pH testing along with the tube length during insertion |
Using a cut off of ≤5.5 for gastric pH was reliable indicator of stomach placement even if patient was on antacids. Auscultation-only method is not as reliable as gastric pH testing or x-ray ** There is insufficient evidence supporting the use of auscultation to confirm accurate gastric tube placement in the emergency department With the possibility of RightSpot technology/products availability, pH testing should be adopted as a safe practice for feeding tube bedside confirmation |
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| 11. Ellett et al., 2014
LOE: II Quality: High |
Prospective comparative design, secondary analysis. Data originally from single blind randomized controlled trial. Sample: N = 276 children, 24 weeks to 212 months of age requiring .nasogastric/orogastric tube placemen | -pH meter vs paper had ICC agreement 0.76.
-pH as a tool to verify GT placement in the stomach has specificity of 87-92.2% but cannot identify placement errors (esophagus or gastroesophageal junction). – Optimal method to determine correct tube placement in the stomach: lack of aspirate from tube (sensitivity 34.9%, PPV 66.7). -Aspirate alone led to multiple misidentified placement locations. |
Aspirate alone led to multiple misidentified placement locations | |||
| 12. Stock et al., 2008
LOE: 6 Quality: Weak |
Design: prospective, observational study Sample: n=404 children | -No difference in pH for gastroenteritis vs. non-gastroenteritis
. -Tube placement confirmed by pH alone in > 84%. pH higher than 4 was associated with incorrect placement; however, all pts. did not receive radiograph for confirmation |
pH testing only useful if aspirate can be obtained | Children, single ED | ||
| 13. Northwell System policy (adult/peds) June 2023
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An X-ray verification is required to confirm placement prior to initiations of feedings/medication administration.
For non-high risk pediatric patients, pH testing may be used to confirm placement -Ng/Og bedside confirmation prior to Xray may consist of pH with a value between 1-5.5
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| 14. Northwell Nursing Clinical Competency, “Nasogastric Tube Maintenance” 12/19 | Attaches a syringe with 10-20 mL of air to the end of the tub.
– Injects air while auscultating the abdomen with a stethoscope. – Listens for “whooshing” sound – Aspirates stomach contents and notes amount, color, consistency, and odor – If unsure of placement obtains order for x-ray to confirm placement. |