University of Virginia Nutrition
This month the journal club coincided with our bi-annual Nutrition Support Forum. The Forum invites dietitians from area hospitals, and combines a journal club with case study presentations and group discussion. Our articles were different than our usual choice of a prospective, double-blind comparison, and were more descriptive in nature to correspond with our forum's discussion. This month our trainees traveled from Kentucky, Arizona and Richmond, Virginia.
#1 Sorokin R, Gottlieb JE. Enhancing patient safety during feeding-tube insertion: a review of more than 2,000 insertions. JPEN J Parenter Enteral Nutr. 2006;30(5):440-5.
This descriptive study reported the incidence of malpositioned feeding tubes, complications of malpositioned tubes, and the results of interventions to decrease the incidence of malpositioned feeding tubes in a 690 bed academic medical center. Feeding tube malpositions were identified via computer search of a risk-management database and a radiology system database over a 4-year period. Feeding tube malpositions were confirmed by chart review.
Major Results reported by authors:
The authors reported 50 confirmed cases of feeding tube malpositions out of 2079 patients, and 14 serious complications from feeding tube malposition. Two deaths were reported to be directly related to malpositioned feeding tubes. The incidence of feeding tube malposition was 1.3% based on the number of feeding tubes purchased, but 2.4% based on the number of radiographs. Only 2 of the complications, and none of the feeding tube misplacements were recorded in the risk-management database.
Interventions implemented to decrease the incidence of feeding tube misadventures included resident education, and a policy for feeding tube advancement to only 35 cm before a confirmatory radiograph is obtained OR advancement with either endoscopy, laryngoscope, fluoroscope or capnometric guidance. The authors reported a decreased incidence of malpositions and complications with feeding tube insertion after their intervention. (0 Complications in 15 months after intervention, and a significant increase in the number of tubes placed between each malposition).
The authors concluded that unassisted feeding tube placement carries a significant risk in vulnerable patients, but this risk can be mitigated with protocols and/or assisted placement. Voluntary reporting of complications (such as a risk management database) is inadequate to capture the occurrence of complications of feeding tube insertion.
There are several limitations of this study, which the authors review in the discussion section of the article. One of the most important limitations is that the actual incidence of misplaced tubes and complications is very likely an underestimation. This was a retrospective review, and the electronic search of radiology database was unable to capture all feeding tubes that were misplaced. The authors identified some tube misplacements via word-of-mouth reporting and one complication from the risk management database that was not captured via their keyword search of the radiology database. In addition, potential complications from tubes placed for non-feeding purposes (such as nasogastric suction) were not evaluated.
The number of feeding tubes that were inserted was estimated from the number of tubes purchased, and the number of radiographs, which may underestimate, or overestimate, respectively, the actual rate of tube misplacement.
There was a decrease in complications and a decrease in the frequency of tube malpositions after the hospital made several changes in the processes of tube insertion. However, there is no way to determine which of the processes implemented by the hospital were necessary or effective because a number of different processes were implemented. The hospital changed to a different feeding tube, and institution-wide education was implemented. All feeding tube insertions had to have a preliminary radiograph at 35cm (unclear if this mandated two x-ray confirmations per patient ?) or be done under some type of guidance. The hospital started actively monitoring all feeding tube malpositions and related adverse events.
Take home message:
Despite this review's limitations, the group felt that this was an extremely valuable study. It reminds us that many facilities do not have an adequate system to identify or record the complications associated from feeding tube placement (none of the forum's participant's hospitals had a formal reporting system). Without a system to identify and track problems, the incidence of complications may go unrecognized, with little attention to the need for implementing protocols necessary to protect the patient from complications of initiating enteral nutrition support (or gastric decompression for that matter).
There is a need for prospective studies to identify the most effective (and cost-effective) protocols for safe insertion of feeding tubes.
#2 Burns SM, Carpenter R, Blevins C. Detection of inadvertent airway intubation during gastric tube insertion: Capnography versus a colorimetric carbon dioxide detector. Am J Crit Care. 2006;15(2):188-95.
The second study was a prospective comparison of two devices used to aid in the insertion of gastric feeding (naso or orogastric) tubes to avoid airway intubation. A disposable colorimetric CO2 detector (Confirm Now) was compared to the results of capnography to detect CO2 during the insertion of 195 gastric tubes in 130 patients in a medical intensive care unit.
Major Results reported by authors:
The researchers placed 195 gastric tubes of 2 different size tubes, including 117 large-bore/salem-sump types (60%), and 78 small bore/dobhoff-type (40%). The route of insertion was oral in 71% and nasal in 29% of patients. Most patients were mechanically ventilated (81%), and most had compromised mental status (72%).
The investigators reported the detection of CO2 during 27% of the tube insertions. There was 100% agreement between the results of the capnograph and the disposable colorimetric CO2 detector. Carbon dioxide was detected by both devices when the gastric tube was advanced to < 30cm.
There were significantly more episodes of CO2 detection during insertion with nasal tubes (p = .03) and with patients that were non-intubated (p = .01).
The authors concluded that a colorimetric CO2 detector is as accurate as capnography for detecting CO2 during assisted gastric tube insertions.
This was not a blinded or randomized study, and there were no comparisons of clinical outcomes (such as number of misplaced tubes) between the two modalities. It utilized a convenience sample of 195 patients to test the efficacy of a disposable colorimetric CO2 detector. It does suggest that a colorimetric device is as accurate as capnography, but there was no objective way to measure sensitivity between the two devices with this study.
The advantage of a disposable colorimetric device is that it is much smaller, and much less expensive than a capnograph. Detection of CO2 before the tubes are advanced beyond 30-35cm should help prevent complications from inadvertent placement of gastric tubes into the airway.
The authors point out that the result of CO2 detection on 27% of the placements is a high rate of airway intubation, and that their methodology cannot exclude the potential for some off these results to be "false" positives.
Take home message:
Use of a colorimetric CO2 detector appears to be as accurate as capnography for the detection of CO2 during gastric tube insertion. There is a need for clinical studies that measure actual tube misplacements with guided versus unguided gastric tube placement, and studies that compare clinical outcomes with different methods to guide placement of tubes.
The forum discussed ways and means of tube placement in the various hospitals. The literature suggests that the issue of misplaced feeding tubes is much more common and serious than many people realize, especially considering that there is often not an organized approach to capture and report these problems.
UVA has started using a colorimetric device to guide placement of all gastric tubes. There is a need for additional research to determine the safest and most cost effective approach to tube placement, but until further studies are available, we want to use the available tools (along with proper training and experienced staff) to optimize patient safety.
1) Weekend Warrior Mini-Nutrition Support Traineeship is coming!
When: Weekend of March 10th and 11th, 2007. Watch our website below for details in the near future:
2) Check out the latest Practical Gastroenterology articles/info at:
Scroll down to GI Nutrition on the far left column and click on link
Then scroll down to box with links within the nutrition site
Nutrition Articles in Practical Gastroenterology is in the right column:
1) Banh, L. Serum Proteins as Markers of Nutrition: What are we treating? Practical Gastroenterology 2006;XXX(10):46.
2) Pagano A. Whole Grains and the Gluten Free Diet. Practical Gastroenterology 2006;XXX(10):66.
Joe Krenitsky MS, RD
Carol Parrish RD, MS
PS - Please feel free to forward this on to friends and colleagues.