If you place a NG due to bowel obstruction or ileus, the gastric contents are not moving through the gut. The body is continuing to produce fluids that are building up in the stomach, causing nausea, vomiting and severe discomfort. You hook the NG up to suction and empty the gastric contents to relieve the pressure, nausea & vomiting. Once suction is pulling off a minimal amount, the MD will usually order the NG to be capped and residuals checked Q4. The sole purpose of NG to suction is to empty the stomach. Now think about this: do you replace what the suction has pulled off? IF the NG is placed to relieve N/V, abdominal distention, due to obstruction or ileus, at least in our facility, the residuals are measured and discarded. They are not returned. 1) The gut is still not functioning enough to move gastric contents from the stomach through the bowel. Anything put into the stomach will just sit there and add to the accumulation (and discomfort). 2) With an ileus or obstruction, the body is not receiving any nutrition from the gastric contents. The balance has already been upset and is hopefully being somewhat restored through IVF's. Discarding gastric residuals in this case will not upset the pH or electrolytes any more than they already are. This sounds really gross but a NG to suction does the same thing vomiting would do. If you threw up, would you put it back to keep the balance? Or would you try to replace it another way (e.g. IVF)?
>>>"Essentially, if you discard it, we won't get a clear picture of pt's motility if we are removing the stomach content." (some number), reconnect to LIS and notify MD."
***IF a NG has been placed to facilitate a tube feed, it's a whole different ballgame and a different set of rules applies. As previously stated, check your facility's policy. Ask your charge. Ask the MD writing the order what she/he wants done. If you tell them what you've been taught, that you hear varying and conflicting advice, and what your thought process is, most are more than happy to explain why you would or wouldn't want to discard in a particular situation.