Nasogastric Lavage in GI Bleeding

WHY DOES THIS MATTER?:

--GI Bleeding can be from an upper or lower source
--consultants/admitting physicians may ask you to place an NG tube and lavage the stomach to help differentiate upper vs. lower GI bleed, if unclear from presentation

DOES IT REALLY HELP?
--2010 review: analysis of 3 limited studies to eval this question: "does nasogastric aspiration and lavage in patients with melena or hematochezia and no hematemesis differentiate an upper from lower source of gastrointestinal (GI) bleeding?"

--prevalence of an upper GI source was 32% to 74%
--sensitivity 42-68%
--specificity 54-91%
--positive predictive value (PPV) 41-93%
--negative predictive value (NPV) 61-78%
--complication rates of NG tube insertion 1.6%.                            

BOTTOM LINE:
--low sensitivity, poor NPV, variable specificity & PPV
--NG lavage has limited diagnostic utility for GI bleed source

Submitted by T. Boyd.

Reference(s): Palamidessi N, et al. Nasogastric Aspiration and Lavage in Emergency Department Patients with Hematochezia or Melena Without Hematemesis.  Acad Emerg Med. 17 (2); Jan 2010, picture