Going with the flow. (preventing clogged feeding tubes)
Author/s: Karen Brennan Krupp
Issue: April, 1998
Find out what problems to anticipate-- and how a few simple steps can
head them off.
A clogged enteral feeding tube that can't be cleared must be replaced
an unwelcome prospect for you and your patient. At the very least,
he'll miss getting some of the fluid and nutrition he needs. At
worst, if he's homebound or a nursing home resident, he'll need to
travel to an appropriate facility for tube reinsertion and X-ray
confirmation of placement. The expression An ounce of prevention is
worth a pound of cure could have been coined by a nurse managing
In this article, we'll describe two simple ways you can keep feeding
tubes patent: pump-assisted infusion of enteral formulas and frequent
tube flushing. But first, let's review factors that can increase the
risk of a clogged feeding tube.
Problems in the pipeline
Feeding tubes can become clogged for one of these reasons:
* calorically dense formulas. When a dense formula is delivered in a
slow, uneven infusion (as by gravity drip), formula coagulation and
tube occlusion are more likely.
* small-bore feeding tubes. Small-bore tubes are more flexible and
less irritating to patients and can be left in place longer than
larger ones. But their smaller lumens make them more likely to clog.
* gravity drip. An imprecise roller clamp adjustment may increase or
decrease the amount of formula delivered by as much as 50%. When
formula flows slowly, residue clings to the wall of the tube,
creating a buildup that eventually clogs the tube.
A slow or stopped flow of formula also causes gastric pH to decrease
because there's less nutritional liquid to dilute the stomach acid.
This excess acid may then flow into the tube, causing the formula to
* medications. Bulk-forming agents such as psyllium (Metamucil),
antacids, and medications that haven't been properly crushed or
reconstituted can also clog a tube. The combination of crushed
medications and a small-bore feeding tube is a common cause of slowed
or blocked formula flow. Whenever possible, administer the liquid
formulation of a medication rather than creating a mixture from
* gastric residuals. When you check gastric residuals through a
feeding tube, gastric acid mixes with the formula in the tube and
causes formula coagulation, which can lead to tube clogging. This
problem is more common when small-bore feeding tubes are used to
aspirate gastric residuals.
An ounce of prevention
Now let's look at the two steps you can take to prevent feeding tubes
A pump-assisted infusion is especially helpful for administering a
calorically dense formula. The slight degree of pump-generated
pressure means the formula is delivered in a continuous, even
infusion, avoiding the problems associated with an uneven
Regular tube flushing with water is, the simplest way to prevent tube
clogging--and the most often neglected. The most common practice is
to instill 50 to 100 ml of water every 4 hours; before, after, and
between multiple doses of medications; and when stopping and starting
a feeding. If you flush the tube consistently, you can clear even
viscous enteral formulas from the tube lumen. Also flush before and
after you check gastric residuals.
Continued from page 1
Cranberry juice, carbonated beverages, meat tenderizers, enzymatic
solutions ... over the years, nurses have tried all sorts of remedies
for clogged enteral tubes. But researchers who've studied various
preventive irrigants have learned something surprising: Nothing beats
plain water. In fact, acidic colas and cranberry juice can actually
cause an obstruction by promoting formula coagulation.
The bottom line? Flushing the tube regularly with water remains the
most effective and practical way to prevent enteral, feeding tube
Making it automatic
A heavy nursing workload and lack of written policies and procedures
for tube flushing can lead to inconsistency in tube flushing. So some
enteral pumps also have an automatic flush feature, which delivers a
preprogrammed amount of fluid, typically water, every hour. This
simulates the flushing action of a syringe and helps minimize residue
Automatic flushing doesn't just save nursing time--it's also more
effective. Two studies found clogging in 75% of gastrostomy tubes in
the manually flushed group, compared with only 5% in the
automatically flushed group. The results were even more dramatic for
nasogastric tubes: 91% in the manually flushed group clogged; none
clogged in the automatic flush group.
By knowing which, factors predispose an enteral tube to clogging and
taking a few preventive measures, you can keep your patient
comfortable- -and save yourself some time.
Brennan, K., et al.: "The Effect of Automatic Flushing on Gastrostomy
Tube Clogging Rates" (abstract), FASEB Journal. 7:A377,1993.
Krupp, K, et al.: "The Effect of Automatic Flushing on Nasogastric
Tube Clogging Rates" (abstract), Journal of the American College of
Nutrition. 12:598, 1993.
Powell, K., et al.: "Aspirating Gastric Residuals Causes Occlusion of
Small-Bore Feeding Tubes," Journal of Parenteral and Enteral
Nutrition. 17(3):243-246, May/June 1993.
Silk, D.: "Enteral Nutrition: Current Clinical Practice: Part III,"
Nutrition 9(1):1-9, January/February 1993.
KAREN BRENNAN KRUPP, RN, BSN Research Nurse Hill Top Research, Inc.
Pharmaceutical Clinical Trials Division Former Clinical Research
BETSY HEMMER, RN, CETN Former Enterostornal Therapy Nurse Consultant
Ross Products Division Abbott Laboratories
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