TPN is the initialism for total parenteral nutrition. Total parenteral nutrition is a method of providing the body with nutrition intravenously. Pharmaceutical company Merck has an online guide to the nutrition found in TPN, with additional warnings regarding complications during use.
Complications may also arise if TPN is stopped abruptly. Patients using TPN are usually put on a step-down plan when TPN needs to be discontinued.
In a TPN study on rats, two groups of rats were put through TPN discontinuation. One group was put through a step-down plan, while the other was discontinued abruptly.
While both groups experienced a significant reduction in spontaneous food intake (SFI), the cumulative caloric intake was much higher in the group that was placed on the step-down plan. This is one goal a physician may have for a TPN patient: to have the optimum caloric intake.
One of the complications of discontinuing TPN abruptly is the development of hypoglycemia. Hypoglycemia is a term used for having an abnormally low blood sugar level. This is a result of the pancreas producing too much insulin in order to handle the glucose in the bloodstream.
Patients receiving TPN may find their physician ordering close monitoring of their blood glucose levels while on TPN and when tapering off from it. The risk for the development of hypoglycemia (sometimes this is called ‘rebound hypoglycemia’) is the reason why.
The recommendation for stopping TPN is a tapering or step-down plan. This may include a transition to enteral nutrition. The plan used will depend upon the health and needs of the patient as well as the judgment of the treating physician.
The Great Debate
There is some debate as to whether tapering off from TPN is actually required and how much of a risk is actually present for hypoglycemia. Even patients with pre-existing diabetes, it is argued, may have only a very low risk for rebound hypoglycemia.
One consideration is that if a patient already has a dependable carbohydrate source, the concern over rebound hypoglycemia is unnecessary and the risk virtually non-existent. Research continues to be done regarding this abrupt stoppage/taper off debate and the complications of discontinuing TPN abruptly.
Total Parenteral Nutrition (TPN). The Merck Manual for Healthcare Professionals. Merck. Last reviewed by David R. Thomas, MD on April 2009. https://www.merck.com/mmpe/sec01/ch003/ch003c.html
The comparative effects of abrupt vs. stepwise discontinuation of TPN in rats. G. Bodoky, AC Campos, ZJ Yang, DC Hitch, MM Meguid. September 1992, 52(3) 591-5. U.S. National Library of Medicine: National Institute of Health. https://www.ncbi.nlm.nih.gov/pubmed/1409925
Total Parenteral Nutrition. 2008. Thomson Healthcare, Inc. https://www.drugs.com/cg/total-parenteral-nutrition.html
What is hypoglycemia? The Hypoglycemia Support Foundation. https://www.hypoglycemia.org/hypo.asp
The Hitchhiker’s Guide to Parenteral Nutrition Management for Adult Patients. Howard Madsen, Eric H. Frankel. Series Editor: Carol Rees Parrish, R.D., M.S. https://docs.google.com/viewer?a=v&q=cache:8xAK6x_SHncJ:www.healthsystem.virginia.edu/internet/digestive-health/nutritionarticles/madsenarticle.pdf+consequences+of+abruptly+stopping+TPN&hl=en&gl=us&pid=bl&srcid=ADGEESj8bCtBP-wSrUAFrJCu8HBtdOwh8xojKd_aWM_VL4atAxBVsfhuB3Sb5iBr9t5FVwyrFlwpz12-o939b4zjh9Ybgdqr8ivvc2u07Yb5QRJWhb7fNdDpMdW3XwqyTv0B7Xvz13yi&sig=AHIEtbQWQzsngjjAV3dejN8u-vmhYoFQLQ