Friday, August 10, 2007

Saturday August 11, 2007
Blue dye in tube feedings

Although initially thought to be without risk and a reasonable indicator of aspiration, the nutritional support community advises AGAINST putting blue dye into tube feeds. Blue dye was thought to be non-absorbable, non-toxic, and sensitive for aspiration. However, now it is hypothesized that blue dye can be absorbed systemically due to increased intestinal permeability and that it can cause decreased mitochondrial oxygen consumption and mitochondrial toxicity.

ASPEN (American Society of Parenteral and Enteral Nutrition) recommends against the use of blue dye in tube feeds. The reasons include:

● The reliability and validity have not been adequately tested.
● There have been reports of skin and body organ staining.
● No safe amount of dye has been established.

Since blue dye is NOT recommended to routinely detect aspiration, prevention is the best treatment. Prevention may include:

● Adjusting rate of administration based on tolerance, bowel sounds, and residuals.
● Elevating the head of bed 45 degrees or more.
● Pro-motility agents.





References: click to get abstract/article

1.
Use of Colored Dyes in Enteral Formulas. REVIEW ARTICLE - Topics in Clinical Nutrition. 21(3):226-233, July/September 2006
2.
Systemic absorption of food dye in patients with sepsis. N Engl J Med 2000;343(14):1046-7.
3.
Skin discoloration with blue food coloring. Ann Pharmacother 2000;34:868-70.
4. Evidence-based practice for enteral feedins:aspiration prevention strategies, bedside detection, and practice changes. Medsurg Nurs 2000;9(1):27-31.
Friday August 10, 2007
Insulin in TPN

Adding insulin to the TPN bag itself - this is chemically compatible and has been done for years. The debate comes in when we start to discuss how much actually makes it to the patient. Study results have been variable. The amount of insulin adsorbed (i.e. stuck to) the glass bottle, plastic bag, or plastic IV tubing can be as high as 80%. Some factors affecting this adsorption include type of container, solution, administration set, previous exposure of tubing to insulin, etc. The binding appears to happen within the first 30-60 minutes. Some in vitro studies have been conducted to assess the effect of "priming" the line with a dilute insulin solution. Priming the tubing with a dilute solution or running through and wasting the first aliquot of the insulin-containing solution increases delivery of insulin from 38% to 85% at 2 hours. Once the priming is done, the amount of insulin delivered remains pretty constant.

Other options - although costly and controversial, adding albumin in small concentrations may help deliver higher amount of insulin by decreasing the amount of insulin available to bind to the container and/or tubing. Adding 0.3 gram/100ml seems to decrease adsorption. Flushing the tubing with the insulin-containing solution two hours before administration seems to saturate the binding sites and minimizes further adsorption. Giving the insulin as a separate IV infusion is another delivery option but adsorption should be considered in this setup as well.