Author: Dr. William Slagle
Article: Nasogastric Aspiration and Lavage in Emergency Department Patients With Hematochezia or Melena Without Hematemesis
This is a paper about GI bleeds and what we should do for them in the ED. GI bleeding can range from mild to severe and can originate from anywhere in the GI tract. This can pose a challenge to the ED physician as the definitive diagnostic and therapeutic procedure, an endoscopy, is not available without calling in a consultant.
It has long been thought that the aspirate from an NG tube could help determine whether bleeding is from an upper or lower GI source. Red or coffee ground aspirate is thought to indicate bleeding is from the upper GI tract and clear or bilious aspirate implies the bleeding is from a lower source. The volume of blood or coffee ground aspirated has also been thought to correlate with the severity of bleeding.
This study aimed to answer the question of how well NG aspiration and lavage could differentiate an upper from a lower source of GI bleeding in ED patients.
This was a systematic review of studies of Emergency Department patients with GI bleeds who received NG aspiration + lavage and EGD. They excluded patients with hematemesis as they already had a presumed upper GI bleed. They also excluded studies involving patients with known esophageal varices due to concern that clinicians would be more cautious placing NG tubes in these patients.
Out of a total of 969 abstracts identified by their search criteria, 3 fulfilled their inclusion and exclusion criteria. These studies found that NG aspirate and lavage had a sensitivity between 42 – 84%. Specificity was between 54 – 91%. Positive predictive value was 41 – 93%. Negative predictive value was 61 – 78%.
This study was a systematic review, although of only three papers. They shared common outcomes of sensitivity, specificity, PPV and NPV. All three studies shared the gold standard of EGD for comparison. The authors came to the conclusion that the data did not support using NG aspirate to differentiate upper from lower GI bleeding. Neither the sensitivity or specificity were high enough to be useful for this purpose. There may still be a role for NG tube placement in determining the severity of bleeding and guiding the timing of an EGD.
Palamidessi, Nicholas. Sinert, Richard. Falzon, Louise. Zehtabchi, Shahriar. “Nasogastric Aspiration and Lavage in Emergency Department Patients With Hematochezia or Melena Without Hematemesis.” Academic Emergency Medicine. February 2010. doi: 10.1111/j.1553-2712.2009.00609.x