Diagnostic accuracy of end-tidal carbon dioxide detection in determining correct placement of nasogastric tube: An updated systematic review with meta-analysis

A prospective observational study of pH testing to confirm ongoing nasogastric tube position

AIMS AND OBJECTIVES

To measure the reliability of pH testing to confirm ongoing nasogastric tube (NGT) position and to document associated complications.

BACKGROUND

Confirming NGT position is essential, as use of an incorrectly positioned tube can cause harm. Substantial evidence examines initial confirmation of NGT position, yet limited evidence exists considers NGT displacement which is identified via ongoing NGT position tests. In the NHS, pH testing is recommended to confirm ongoing NGT position; however, there may be an association with excess X-rays and missed enteral nutrition and/or medications.

DESIGN

Prospective observational study using STROBE checklist.

METHODS

Data collected from medical records of 136 patients with NGTs in a London NHS Trust included pH tests, test results and complications related to ongoing pH tests which failed to confirm the tube was positioned in the stomach, that is, X-rays, and disruptions to enteral nutrition and medication. Cohen's Kappa determined pH test reliability.

RESULTS

Of 1381 pH tests conducted to confirm NGT position, five (0.3%) correctly identified an NGT displacement, and one (0.07%) failed to identify displacement before use. The reliability of ongoing pH tests using Cohen's Kappa was minimal (0.29). Ongoing pH tests that failed to confirm a correctly positioned NGT led to 31 (22.8%) patients having X-rays, 24 (17.6%) missing >10% of prescribed enteral nutrition and 25 (18.4%) missing a critical medication.

CONCLUSION

Ongoing NGT position testing using pH tests did not prevent the use of a displaced tube, and more than one-fifth of patients required X-rays to confirm a correctly position NGT, contributing to missed medications and enteral nutrition.

RELEVANCE TO CLINICAL PRACTICE

Caution should be used when confirming ongoing NGT position with a pH test. Future guidelines should balance the risk of using a displaced tube with potential delays to nutrition and/or medication. More research is needed to explore alternative methods of ongoing NGT position testing.

Use of Tumguide® in the Insertion of a Nasogastric Tube Into the Stomach of a Patient With Creutzfeldt-Jakob Disease in a Nursing Home: A Case Report

A 77-year-old woman exhibited a rapid progression of dementia and declining physical function and, over a period of about four months, reached a state of akinetic mutism. A final diagnosis of Creutzfeldt-Jakob disease (CJD) was made. A nasogastric tube was inserted into the stomach, and then it was confirmed on X-ray that the end of the tube was in the correct position. She was discharged to a nursing home, where she received home medical care after discharge. One month after the nasogastric tube insertion, Tumguide® was used to assist in replacing the tube at this home. In home care settings where an X-ray machine may not be available, Tumguide® may assist with nasogastric tube insertion.

Diagnostic accuracy of using capnography in verification of nasogastric tube placement among adult patients in hospital settings: Protocol of a diagnostic study

OBJECTIVE

To determine the diagnostic accuracy of end-tidal carbon dioxide (ETCO2) detection using capnography for verifying the correct placement of nasogastric tubes (NGTs) among adult patients in hospital settings.

MATERIALS AND METHODS

A prospective observational diagnostic study will be conducted. Patients ≥ 18-year-old and requiring the insertion of an NGT will be recruited using a convenience sampling method from 39 general medical and geriatric wards, intensive care units, accident and emergency departments, and subacute/rehabilitation/infirmary wards in 21 acute or subacute/convalescent/extended care hospitals. ETCO2 detection by sidestream capnography, which indicates an airway intubation of an NGT when a capnogram waveform or an ETCO2 level > 10mmHg (1.33 kPa) occurs, will serve as the index test. The reference standards will be the X-ray performed and pH value of gastric aspiration (pH ≤ 5.5) after the index test. Each participant will be included only once. Sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve of capnography will be calculated to assess the diagnostic performance of capnography. The variability in diagnostic accuracy in participants with different characteristics will be explored by using chi-squared or Fisher's exact tests. The time spent and the cost of the tests will be compared using the paired t-test. All statistical tests will be two-sided with a level of significance set at 0.05.

DISCUSSION

This study will provide evidence on the diagnostic accuracy of capnography in verifying NGT placement and its applicability to patients in hospitals settings, since this evidence is limited in the current literature. In addition, it will help identify the optimal combination of tests in verifying the correct placement of NGTs and inform the update of clinical practice guidelines and stakeholders' decisions on the adoption of ETCO2 detection as a routine method for verifying NGT placement.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT05817864.

Nasogastric tube insertion length measurement and tip verification in adults: a narrative review

Nasogastric feeding tube insertion is a common but invasive procedure most often blindly placed by nurses in acute and chronic care settings. Although usually not harmful, serious and fatal complications with misplacement still occur and variation in practice still exists. These tubes can be used for drainage or administration of fluids, drugs and/or enteral feeding. During blind insertion, it is important to achieve correct tip position of the tube ideally reaching the body of the stomach. If the insertion length is too short, the tip and/or distal side-openings at the end of the tube can be located in the esophagus increasing the risk of aspiration (pneumonia). Conversely, when the insertion length is too long, the tube might kink in the stomach, curl upwards into the esophagus or enter the duodenum. Studies have demonstrated that the most frequently used technique to determine insertion length (the nose-earlobe-xiphoid method) is too short a distance; new safer methods should be used and further more robust evidence is needed. After blind placement, verifying correct gastric tip positioning is of major importance to avoid serious and sometimes lethal complications.