One of the worst-tolerated procedures in Emergency Medicine – placement of the NG tube. Unfortunately, when I call my GI fellow on-call for any upper GI bleeding, the first question is invariably – what did the NG lavage show?
There is good evidence demonstrating that positive NG lavage tends to identify the presence of high-risk lesions found on subsequent endoscopy. There is also evidence that endoscopic treatment of high-risk lesions decreases rebleeding and mortality. So, if NG lavage identifies high-risk lesions, and endoscopic treatment of high-risk lesions decreases mortality, then patients who undergo NG lavage for their upper GI bleeds should have lower mortality, right?
This is a retrospective review of all the patients admitted to the West LA VA with a diagnosis of upper GI bleeding – a sample of 632 meeting inclusion criteria. Of these, 255 did not undergo NGL and 378 did. What’s interesting in this article is that the authors attempted to statistically create two identical cohorts using propensity scoring. They ended up with two nearly identically matched cohorts of 193 patients from the original 632 based on demographics, triage, lab values, physiologic characteristics, and medical interventions.
Between these two groups, they found no significant difference between mortality, hospital stay, emergency surgery, and blood transfusion requirements. There was a statistically significant difference in the number of patients who underwent endoscopy – patients who didn’t receive NGL had 60% endoscopy vs. 72.3% in the NGL group. This is mildly interesting – considering that, in theory, the identification and endoscopic treatment of high-risk lesions is associated with increased survival – and if you’re doing less endoscopy on an identical patient cohort, you should be missing the opportunity to treat those lesions. Yet, there was no significant difference outcomes between cohorts.
So, yes, if you wanted to stop placing NG tubes because they’re uncomfortable for patients and apparently don’t change ultimate outcomes – certainly, that may be reasonable. Some gastroenterology literature suggests patient-specific risk factors are more important in predicting the impact of endoscopic intervention on outcomes, rather than the limited information derived from the NG lavage.
However, this is just statistical calisthenics in an attempt to replicated a randomized-controlled trial and doesn’t give us the prospective evidence needed to change practice. Or argue over the phone with the GI fellow.
“Impact of nasogastric lavage on outcomes in acute GI bleeding”
http://www.ncbi.nlm.nih.gov/pubmed/21737077