I Hereby Declare the End of the Reflexive NG Tube

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The use of NG tubes is just one of many procedures where EPs take a traditional approach that lacks evidence to support it. A closer look at the research shows that the benefits of NG tubes may not outweigh the discomfort.

When I was applying for medical school, there were only five in my hometown of Philadelphia and I applied to all five. When I toured Jefferson Medical College I heard they inserted nasogastric tubes (NG) on each other – I scratched Jefferson off the list.

When it comes to noxious routine ED procedures, the insertion of an NG tube is right at the top of the list. The most effective way to limit the angst of placing an NG tube is to not do them. The literature says NG tubes are usually unneeded in GI bleeding, small bowel obstruction and pancreatitis – three indications that had been routine in the past (and their use for gastric lavage in the setting of suspected overdoses is pretty much a very uncommon circumstance). In the setting that an NG tube is appropriate, anesthetizing the oropharynx with atomized lidocaine can decrease gagging and discomfort.

The great title of the first paper reflects the patient anxiety when advised of the need for an NG tube. This classic paper by Mike Witting focuses on the decreased indications for an NG tube, particularly as it related to upper gastrointestinal bleeding (UGI).

Nasogastric intubation (NGI) is associated with considerable discomfort and the potential for com- plications. Recent studies have questioned the need for NGI for “traditional” indications. The author, from the University of Maryland, reviews the use of NGI in selected clinical conditions. The evidence supports selective use of NGI in patients with gastrointestinal bleeding. In patients with hematemesis, NGI has not been definitively demonstrated to have positive effects on decision-making. Because endoscopy is the definitive procedure for these patients, this author suggests that decisions about the need for prior NGI be discussed with the endoscopist. If immediate endoscopy is planned, NGI is not likely to be necessary. In the absence of hematemesis, NGI is felt to have little utility in patients without risk factors for an upper GI source of bleeding (black stool color, a BUN/ creatinine ratio above 30, and age below 50). This author suggests that an upper GI source is unlikely in patients without these risk factors and is probable in those with two or more risk factors (for whom a need for NGI should be discussed with the endoscopist), and that NGI is most likely to be useful in patients with a moderate pretest probability of an upper GI source of bleeding (i.e., those with one risk factor). Routine use of NGI is not supported for patients with metastatic small bowel obstruction or paralyticileus, or for the administration of activated charcoal; the author suggests selective use of NGI in such patients. Finally, studies have shown no benefit of NGI (and the possibility of producing more harm than good) in patients with pancreatitis or isolated large bowel obstruction. Techniques to limit the discomfort of NGI and to facilitate the passage of the NG tube are also reviewed. 22 references 11/07 – #23

This next study is a systematic review and meta-analysis of five papers looking at pain relief during NG tube insertion. It compares nebulized lidocaine with saline placebo. Each of the studies individually did not show a statistically significant decrease in pain, however, when combined, statistical power was achieved and a 58% reduction was shown. This is a great example of how small studies may be underpowered to show that true differences exist be- tween therapies. Seems that warming the tube so that it is subtle, using some lidocaine jelly in the nose in advance and using some lidocaine jelly on the tube – all combined with nebulization of lidocaine would seem to be a logical progression.

BACKGROUND: Nasogastric tube insertion has been noted to be one of the most painful procedures performed in the ED. Studies reporting a beneficial effect of aerosolized lidocaine on the discomfort of NG tube insertion have yielded inconclusive results due to methodologic limitations.
METHODS: These Chinese authors performed a systematic review and meta-analysis of five randomized controlled trials (212 subjects) comparing the effects of nebulized lidocaine or placebo on the discomfort of NG tube insertion.
RESULTS: All five studies compared aerosolized lidocaine vs. saline placebo. The five studies were all judged to be of higher methodologic quality. The mean patient age was 59.6 years in the active treatment groups and 55 years in controls, and 58% of the subjects were female. Two studies assessed the effects of administration of 10% lidocaine via a face mask or nasal atomizer, and 4% lidocaine was administered in the remaining three studies. All five studies individually reported a reduction in the pain of NG tube insertion with the active intervention that did not achieve statistical significance, but the pooled effect size was statistically significant (OR 0.423) and consistent with a 57.7% reduction in discomfort with the lidocaine intervention compared with the administration of normal saline.
CONCLUSIONS: One study reported that fewer than one in five patients is pretreated with nebulized anesthetic prior to NG tube insertion in the ED. The findings of this meta-analysis are consistent with a significant reduction in the discomfort of this procedure with administration of nebulized lidocaine. 22 references (miaofen@mail.ncku.edu.tw – no reprints) 4/11 – #15

Now, let’s look at the use of NG lavage or suction in the setting of GI bleeding. It has long been ritual that an NG tube be inserted in patients with UGI bleeding or to ascertain whether positive rectal bleeding is coming from an UGI source. The first study was a chart review of 632 patients presenting with UGI bleeding. 60% had GI lavage performed before endoscopy. No difference in any of multiple outcomes was found in those who had lavage and those who didn’t except that endoscopy was performed more frequently in the NG lavage group (72.3% vs. 60.1%) and was done earlier in the course of treatment. This be- ing the case, it may be best to ask the GI consultant his/ her desire regarding the need for lavage and the timing of endoscopy.

IMPACT OF NASOGASTRIC LAVAGE ON OUTCOMES IN ACUTE GI BLEEDING Huang, E.S., et al, Gastrointest Endosc 74(5):971, November 2011
BACKGROUND: Guidelines for the management of acute nonvariceal upper gastrointestinal bleeding do not address routine performance of nasogastric lavage prior to endoscopy. It has been observed that the beliefs of both academic and community-based providers about routine use of NG lavage in such patients is quite variable.
METHODS: The authors, from the West Los Angeles VA Medical Center, performed an implicit chart review to assess the relationship between performance of NG lavage and clinical outcomes in 632 patients (mean age 63, 98% male) presenting with acute GI bleeding.
RESULTS: NG lavage was performed prior to endoscopy in 193 patients (60%), who were propensity-matched (for 19 variables related to the likelihood of undergoing NG lavage) to 193 patients not so treated. Baseline characteristics were similar in the two groups. In this cohort, there were no statistical intergroup differences in 30-day mortality (11% in the NG lavage group vs. 13% in controls, odds ratio [OR] 0.84, 95% CI 0.37-1.92), the duration of the hospital stay (7.3 vs. 8.1 days), blood transfusion requirements (3.2 vs. 3.0 units of packed red cells) or the need for emergency surgery (3.1% vs. 2.1%). However, endoscopy was performed more frequently in the NG lavage group (72.3% vs. 60.1%), and was done earlier in the course. A finding of bloody aspirate on NG lavage correlated with demonstration of high-risk lesions on endoscopy (OR 2.69), but performance of NG lavage did not.
CONCLUSIONS: In this study, performance of nasogastric lavage in patients with acute GI bleeding was associated with earlier performance of endoscopy, but was unrelated to clinical outcomes. 31 references (bspiegel@mednet.ucla.edu for reprints) 4/12 – #15

Next, a literature review involving three studies and 533 total patients identified a rate of confirmed upper GI bleeding in the three studies ranged from 32% to 74%. The sensitivity of nasogastric aspiration and lavage in diagnosing upper GI hemorrhage in the three studies was 42%, 68% and 84%, respectively, and corresponding specificities were 91%, 54% and 82%, respectively. Negative predictive values ranged between 61% and 78%, and positive predictive values ranged from 41% to 93%. Due to the limited utility of NG aspiration to exclude UGI bleeding, both upper and lower endoscopy will be required.

BACKGROUND: Insertion of a nasogastric tube has been cited as one of the most uncomfortable procedures performed in the ED, and has the potential to produce significant complications. Nasogastric aspiration and lavage is often performed in ED patients to identify or exclude an upper gastrointestinal source of bleeding, but there is uncertainty about its diagnostic value.
METHODS: The authors, from the State University of New York in Brooklyn, performed a literature review to identify studies of the utility of nasogastricaspiration and lavage to identify an upper GI bleeding source in ED patients with hematochezia or melena in the absence of hematemesis. Three retrospective studies that included 533 patients without hematemesis were identified.
RESULTS: The three studies included heterogenous patient populations. Esophagogastroduodenoscopy results were the reference standard in two studies, and the hospital course combined with the results of surgery, endoscopy or other imaging were the reference standard in the third study. The rate of confirmed upper GI bleeding in the three studies ranged from 32% to 74%. The sensitivity of nasogastric aspiration and lavage in diagnosing upper GI hemorrhage in the three studies was 42%, 68% and 84%, respectively, and corresponding specificities were 91%, 54% and 82%, respectively. Negative predictive values ranged between 61% and 78%, and positive predictive values ranged from 41% to 93%.
CONCLUSIONS: Nasogastric aspiration with or without lavage appears to have limited utility in excluding an upper GI source of bleeding in patients with hematochezia or melena without hematemesis. Regardless of the nasogastric aspirate result, both high and low endoscopy will be required for diagnostic confidence. 25 references (npdessi@hotmail.com for reprints) 6/10 – #18

Routine insertion of an NG tube in small bowel obstruction is not defended by the literature. The following small study tries to ascertain which patients may do well without an NG tube, but the small numbers make if very hard to get much in the way of take home. Ultimately, 52 of 290 adults were managed without NG decompression. Nonoperative management was successful for two-thirds of the patients not getting an NG tube.

BACKGROUND: Although nonoperative management of patients with small bowel obstruction (SBO) often includes nasogastric decompression, there are no studies that document a need for this intervention on a routine basis.
METHODS: The authors, from Yale University, per- formed an implicit chart review in 290 adults (average age, 58) admitted with SBO over a five-year period in an attempt to identify those who might be safely managed without an NG tube. The study included patients with adhesive or malignant obstruction, but not those with an obviously incarcerated hernia.
RESULTS: Fifty-five patients (19%) were managed without NG decompression. These patients had a higher rate of abdominal distension and tympany on presentation than those who underwent immediate NG tube insertion. Although most patients in both groups had nausea and/or vomiting on presentation, an NG tube was placed in three-fourths of the patients without nausea and/or vomiting. Most of the patients undergoing NG decompression (63.8%) had minimal NG tube drainage (less than 500ml in 24 hours). Nonoperative management was successful for two-thirds of the patients; the success of conservative management was not associated with NG tube placement. Patients who underwent NG decompression had a longer time to resolution of SBO than those not so managed (3.6 vs. 1.7 days), a longer length of stay (10.2 vs. 3.2 days), a higher complication rate (odds ratio [OR] 19.3), and more frequent discharge to a rehabilitation facility or nursing home. (OR 6.6); it is impossible to assess causality based on these findings, however.
CONCLUSIONS: Some patients hospitalized with small bowel obstruction do well without nasogastric decompression. 29 references (kevin.schuster@yale. edu for reprints) 5/14 – #17

Finally, everybody knows that patients with pancreatitis need an NG tube. The theory is that sucking out the stomach juices that are the stimulus for the pancreas to secrete will put the pancreas at rest and accelerate the recovery process. But is that actually the case? Here is a really old paper that affirms others and suggests that patients with mild to moderate severity don’t benefit from an NG tube and may do better without it.

Nasogastric suction has traditionally been employed in the management of patients with acute pancreatitis. This random, prospective, controlled study, from the Johns Hopkins Hospital in Baltimore, analyzed the effects of NG suction in 60 patients with a diagnosis of mild (59) or moderate (1) acutepancreatitis. Twenty-nine patients were managed with at least 48 hours of nasogastric intubation (mean, 4.4 days) in conjunction with low, intermittent suction, and 31 comparable patients were managed without NG suction. Analysis of the hospital courses of these patients indicated that the duration of fever, abdominal tenderness, and absence of bowel sounds and bowel movements, the need for narcotics and IV fluid therapy, and the prevalence of serious complications of acute pancreatitis were comparable in the two treatment groups. Patients managed with NG suction resumed oral intake 5.0 days after admission, compared to 3.9 days in patients managed without NG suction (p<0.01). The patients managed with NG suction had a longer duration of hyperamylasemia and a longer duration of hospitalization than patients managed without this modality, but these differences did not achieve statistical significance. The conclusions of this study confirm the data of other investigators who have demonstrated no benefit associated with routine use of NG suction in patients with acute pancreatitis of mild to moderate severity, but may not apply to individuals with severe pancreatitis. 20 references 3/87-#23

There are lots of ED procedures that have been ingrained into our psyche as “standard of care” – often without good evidence to support their use. For the benefit of our patients emergency providers need to be willing to shine the searchlight of scientific inquiry at many of the dogmas to which we adhere.


Dr. Bukata is the Editor of Emergency Medical Abstracts.

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