Measures to test placement of nasoenteral feeding tubes

Implementation of the evidence review on best practice for confirming the correct placement of nasogastric tube in patients in an acute care hospital

BACKGROUND

Nasogastric (NG) tube is a device passed through the gastrointestinal tract of patients for the purpose of feeding, gastric decompression and medication administration. However, a small risk involved in the process is that the tube may be misplaced into the trachea during insertion or may get displaced at a later stage, leading to disastrous results. Recent adverse incidences arising out of the misplacement of NG tube raised concerns among the nursing and medical community and the Patient Safety Officer of the hospital. The Evidence Based Nursing Unit, in collaboration with some of the key nursing leaders in nursing administration, was tasked to explore and institute the current best practice in confirming the correct placement of NG tube.

AIM

The aim of this project was to institute the best practice to confirm the correct placement of NG tube in patients in an acute care hospital setting.

METHOD

The project comprised of a few stages. The first stage involved reviewing the existing recommendations and guidelines on the methods for checking correct NG tube placement. The second stage involved incorporation of the change of practice into the clinical setting. The final stage was to monitor and evaluate the impact of the new practice on the patients, nurses and other healthcare professionals.

RESULTS

Evidence search from guidelines and journals supported the test that used pH indicator instead of the litmus test. There is no evidence that supports the method of auscultation and bubbling to confirm correct NG tube placement in the absence of aspirate. Radiology remains the 'gold standard' for checking correct NG tube placement. The revised method of NG tube placement and workflow was incorporated in the revised Standard Operating Procedures. A total of 17 roadshows were conducted to create awareness regarding the new method amongst the nurses, and the implementation of the revised method and workflow was commenced on 3 November 2008. The initial audit conducted 1 month after the practice change was implemented reported 26 (50%) observations of NG tube feeding in 26 audit wards. The key areas of practice change in feeding when tube placement was confirmed (84.6%) and proper testing of aspirate (76.9%) showed good compliance.

CONCLUSION

The implementation of the change in the practice of confirming the correct placement of the NG tube in patients requires good coordination and a multidisciplinary team approach.

Methods for determining the correct nasogastric tube placement after insertion: a meta-analysis

BACKGROUND

Nasogastric tubes are frequently used in the clinical setting for the management of patients who require decompression of the gastrointestinal tract, diagnosis and assessment, nutritional support and medication administration. A variety of bedside methods have been used either individually or in combination to assess NG tube placement.

OBJECTIVES

The objective of this review is to present the best available evidence to support decisions pertaining to methods for determining the correct nasogastric tube placement after insertion.

SEARCH STRATEGY

A literature search was performed using the following databases MEDLINE (1950 to Sept 2008), CINAHL (1982 to Sept 2008), EMBASE (1980 to Sept 2008) and All EBM Reviews (up to 3rd Quarter 2008). Chinese databases searched included WanFang Data (1998 to Sept 2008), China Journal Net (1994 to Sept 2008), Chinese Medical Current Contents (1994 to Sept 2008), Index to Chinese Periodical Literature (1970 to Sept 2008), and the Chinese Biomedical Literature Database (1980 to Sept 2008). In addition the reference lists of relevant trials and conference proceedings were also scrutinised. Investigators were contacted to elicit further information.

SELECTION CRITERIA

Clinical trials, prospective studies, observational studies, case reports, and evaluation studies assessing the diagnostic accuracy of methods for determining the correct placement of nasogastric tube after insertion were considered for inclusion in the meta-analysis.

DATA COLLECTION AND ANALYSIS

Eligibility of the trials for inclusion in the review, details of eligible trials and the methodological quality of the trials were assessed independently by two reviewers. Since not all trials reported true positive, true negative, false positive and false negative rates, these rates were calculated based on the data in the published papers. The two by two tables were reconstructed for each study, and sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio were calculated for each study. Diagnostic studies presenting insufficient data for construction of a two by two table were excluded from statistical analysis, but were included in the narrative part of the review.

MAIN RESULTS

Twenty-six trials were included in this meta-analysis: three trials investigated the effectiveness of colorimetric capnometry in detecting inadvertent airway intubation; three trials reported the use of capnography to verify tube placement in airway and to differentiate between respiratory and GI tube placement; one trial compared the use of a portable capnograph with a disposable colorimetric CO2 indicator in detecting inadvertent respiratory intubation. There were nine trials made use of a variety of cut-off points based on the biochemical measurement parameters of feeding tube aspirates (pH, bilirubin, pepsin and trypsin) in differentiating gastric from respiratory and intestinal placement of feeding tubes; one trial evaluated the accuracy of six pH test-strips. There were nine trials investigated the effectiveness of using various methods to differentiate between respiratory and GI feeding tube placement which included the use of: spring gauge pressure manometer, magnetic detection, sonography, auscultation and visual inspection of aspirates.

AUTHORS' CONCLUSION

The limited evidence obtained from the meta-analysis does not provide a substantial base for the development of practice guidelines. However, based on the trials undertaken to date, there is strong evidence to support the use of capnography or colorimetric capnometry for identification of feeding tube placement in mechanically ventilated patients. Until stronger evidence becomes available practice related to the diagnostic tests used within the clinical setting will continue to be dictated by local preferences and cost factors.

Detection of Inadvertent Airway Intubation During Gastric Tube Insertion: Capnography Versus a Colorimetric Carbon Dioxide Detector

• Background In the medical intensive care unit at the University of Virginia Health System, capnography is used to detect end-tidal carbon dioxide to protect patients from inadvertent airway cannulation during placement of gastric tubes.

• Objectives To compare the method in which capnography is used with a method in which a colorimetric carbon dioxide detector is used and to determine what variables affect accurate placement of gastric tubes.

• Methods A prospective convenience sample of 195 gastric tube insertions was studied in 130 adult patients in a medical intensive care unit. Standard insertions of gastric tubes (done with capnography) were simultaneously monitored by using a disposable colorimetric device, with a color change indicating the presence of carbon dioxide.

• ResultsInsertion variables included tube type (60% Salem sump tubes, 40% soft-bore feeding tubes), route of insertion (71% oral, 29% nasal), mechanical ventilation (81%), and decreased mental status (72%). Carbon dioxide was successfully detected with the colorimetric indicator (within seconds) in all insertions in which carbon dioxide was detected by capnography. When carbon dioxide was detected (27% of insertions), the tubes were withdrawn and reinserted. Carbon dioxide detection during tube placement was significantly associated with nasal insertions (P = .03) and spontaneously breathing/nonintubated status (P=.01) but not with mental status or tube type.

• Conclusions A colorimetric device is as accurate as capnography for detecting carbon dioxide during placement of gastric tubes.

What Is Known About Methods of Correctly Placing Gastric Tubes in Adults and Children

An abdominal radiograph is considered the "gold standard" for determining the position of flexible small-bore nasogastric/orogastric tubes. However, placement must be checked frequently while a tube is in place, and the summative radiation risk of multiple radiographs, as well as their expense, make the development of adequate bedside placement-locating methods imperative. Several methods of detecting tube placement have been investigated in adults, including: aspirating gastric contents and measuring the pH, bilirubin, pepsin, and trypsin levels; examining the visual characteristics of aspirate; placing the proximal end of the tube under water and observing for bubbles in synchrony with expirations; measuring the carbon dioxide level at the proximal end of the nasogastric/orogastric tube; auscultation for a gurgling sound over the epigastrium or left upper quadrant of the abdomen; and measuring the length from the nose/mouth to the proximal end of the tube. Many researchers have already concluded simple auscultation is not a reliable method to assess tube position because injection of air into the tracheobronchial tree or into the pleural space can produce a sound indistinguishable from that produced by injecting air into the gastrointestinal tract. In adults, only pH and bilirubin of aspirate have been shown both to reliably predict tube position and to have inexpensive simple bedside tests. In children, only pH of aspirate has been shown to be reliable. Research on gastric tube placement in children is relatively new because children are challenging to study in that they are considered a vulnerable population. This review of the literature includes results of both adult and pediatric studies. Tube placement error rates varied from 1.9% to 89.5% in adults and between 20.9% and 43.5% in children.

A controlled comparison of traditional feeding tube verification methods to a bedside, electromagnetic technique

BACKGROUND

Benefits of enteral feeding are diminished by aspiration pneumonia and mechanical complications of misplaced feeding tubes. To avoid complications, clinicians determine the location of the tip before feeding. This study compares diagnostic test characteristics of 4 techniques for tip localization.

METHODS

A prospective, blinded trial was conducted on the wards and critical care units of four acute-care hospitals. Patients requiring at least 3 days of enteral feeding were studied. Four observers at each institution used a randomly assigned technique to determine a tube's tip location. Methods included auscultation, aspiration with inspection or pH determination of aspirated material, and a recently developed electromagnetic technique. Results were compared with radiographic determination. Success rates were compared using sensitivity, specificity, and likelihood ratios.

RESULTS

The 4 methods agreed with the radiograph in (mean, 95% confidence interval): 84 (80 to 88)%, 50 (45 to 55)%, 56 (51 to 61)%, and 76 (72 to 81)% of observations, respectively. Only the electromagnetic method and aspiration identified all tubes located above the diaphragm (negative likelihood ratio 0 and sensitivity 100%). Aspiration was unsuccessful in making a determination in 53% of the observations, whereas the electromagnetic method was successful 90% of the time.

A validation study using the case-control method of the nursing diagnosis high risk for aspiration

PURPOSE

To develop further the nursing diagnosis risk for aspiration by determining risk factors present in patients who aspirated.

METHODS

The case-control design was used to compare cases (n = 131) and controls (n = 206) on past and present exposures thought to be risk factors for aspiration. Data were analyzed using univariate and multiple logistic regression.

FINDINGS

The following risk factors were statistically significant and comprise the final model: altered level of consciousness, metoclopramide (known to accelerate gastric emptying), vomiting, seizures, and unable to change own position.

CONCLUSIONS

The risk factors of altered level of consciousness and delayed gastric emptying are currently included in the NANDA taxonomy for the nursing diagnosis risk for aspiration. These risk factors are not included in the taxonomy: vomiting, seizures, and unable to change own position. Results of the study have been submitted to the Diagnosis Review Committee for consideration to further develop this diagnosis.

Gastric decompression in adult patients. Survey of nursing practice

Using a 62-item investigator-developed mailed questionnaire, this descriptive study of 350 randomly selected staff nurses sought to identify variations in practices in the care of patients with nasogastric tubes. Reported here are the results on the 15 questionnaire items related to the use of nasogastric tubes for gastric decompression. Results show that practice is not always consistent with published research; additionally, there are areas of practice for which no research was found. Subjects' responses by age, education, and amount of experience showed marked frequency variations on several items, as did employment in teaching versus community hospitals. Results have implications for nursing educators in clinical agencies and nursing schools.

Nasogastric tubes: insertion, placement, and removal in adult patients

Using a 62-item, investigator-developed, mailed questionnaire, this descriptive study of 350 randomly selected staff nurses sought to identify variations in the care of patients with nasogastric tubes (NGT). Reported here are the results of the 12 questionnaire items related to insertion, checking placement, and removal. Results showed that practices related to checking placement do not consistently reflect published research. Variations were noted by age and experience. Practices also varied between teaching and community hospitals. Findings have relevance for nurse educators in clinical agencies and nursing schools.

Nursing research and nursing practice--teaching the inseparable duo

This series of research courses provides (a) an initial emphasis on learning the content at the knowledge and comprehension levels; (b) sequential and continuous courses so that research is not seen as isolated, and therefore esoteric, knowledge; (c) an application component congruent with the clinical/practice needs and interests of students; and (d) low faculty-student ratios, at least some of the time. Teaching research so that it becomes a fundamental part of nursing practice is a goal that must be met. Reading and critiquing research provides an ideal avenue for stimulating and embellishing the critical-thinking abilities that are so basic to excellence in practice. The development of nursing science and the complexities involved in enhancing patient well-being depend on the promotion of nursing research and the clinical application of nursing research findings. Knowledge about nursing research must be taught; structuring teaching so that nursing research becomes a valued and inherent part of clinical practice from the beginning is the challenge for nursing educators.

Use of a pressure gauge to differentiate gastric from pulmonary placement of nasoenteral feeding tubes

This study was conducted to determine the reliability and validity of using a pressure gauge to differentiate gastric from pulmonary placement of nasoenteral tubes in nonmechanically ventilated patients. It was anticipated that on inhalation, tubes properly placed in the gastric region would yield positive readings owing to positive gastric pressures. Conversely, tubes that were inadvertently placed in the pulmonary system should yield negative pressure readings owing to the negative pulmonary pressures that exist on inhalation. Forty-six subjects were enrolled in the study. Of those, 44 had positive gauge readings, and x-ray results showed that these nasoenteral tubes were in the gastric region. Two patients had negative gauge readings, and the x-rays for both of these subjects demonstrated that the nasoenteral tubes were in the pulmonary system. Thus, the findings were consistent with what was anticipated. Despite the small sample size, the results of this study indicate that this method of assessing nasoenteral tube placement may be a safe, reliable, and cost-effective method of differentiating gastric from pulmonary tube placement in this patient population.

Intestinal placement of pH-sensing nasointestinal feeding tubes

Intestinal access for enteral nutrition can be achieved by spontaneous intestinal nasogastric tube passage or by endoscopic, fluoroscopic, or surgical placement methods. Each of these methods has limitations that may compromise clinical utility. pH-sensing nasointestinal feeding tubes allow active placement with minimal equipment and expertise; however, this method requires an acidic gastric pH. We sought to determine whether antiulcer regimens used at our institution would preclude intestinal pH-sensing tube placement. Twenty-five patients had 25 (81%) successful intestinal placements in 31 attempts. Observed pH values and calculated pH changes were compared within and between successful and unsuccessful groups by using a Student's t test. Initial, lowest, and final pH values did not differ significantly between groups. The pH change initial-to-lowest (4.7 +/- 0.18 vs 3.6 +/- 0.59, p < .03) and lowest-to-final (5.0 +/- 0.18 vs 3.0 +/- 0.47, p < .0001) differed significantly between groups, whereas the pH change initial-to-final did not. Cost analysis of endoscopic ($782), fluoroscopic ($341 to $382), spontaneous ($167 to $212), and pH-sensing ($162) methods revealed 3% to 79% savings when the pH-sensing placement method was used. We conclude that the antiulcer therapies used in our patient population did not preclude intestinal pH-sensing tube placement. If the pH changes from initial-to-lowest and lowest-to-final were greater than 4, successful intestinal placement occurred in 91% of attempts. Finally, the method was cost-effective at our institution.