Di-2-ethylhexyl phthalate (DEHP) is a family of chemicals called phthalates. These chemicals are used to make polyvinyl chloride (PVC) plastic tubing soft and flexible. Because DEHP does not bind to the plastic, it can leach out of the PVC products. DEHP is widely used in PVC disposable medical devices. As in other products, DEHP can leach out of flexible PVC medical devices into the solution or medication it contains and subsequently into the patient (Rubin & Schiffer, 1976).
DEHP concentrations in blood and blood products are of particular concern for babies who receive regular blood transfusions. The most commonly used blood products, packed red blood cells and plasma are typically stored in DEHP plasticized bags and administered to patients through DEHP plasticized intravenous tubes. Less common treatments that involve potentially high DEHP exposures are blood exchange transfusions and extracorporeal membrane oxygenation (ECMO). Although potential exposure to DEHP in ECMO patients is significant, it has not been associated with a short-term toxicity.
Why We Were Concerned
When DEHP enters the human body, the compound is metabolized into various substances that are more rapidly excreted. The most important of these metabolites, mono-ethylhexyl phthalate (MEHP), is thought to be responsible for much of DEHP's toxicity. The enzymes that break down DEHP into MEHP are found mainly in the intestines but also occur in the liver, kidney, lungs, pancreas, and plasma. Because conversion of DEHP to MEHP occurs primarily in the intestinal tract, exposures to DEHP by ingestion may be more hazardous than by intravenous exposure, which largely bypasses the intestinal tract (Huber, Grasl-Kraupp, & Schulte-Hermann, 1996).
Human exposure to plasticizers in a form of DEHP occurs throughout life. Of particular concern is the exposure of fetuses, preterm infants, and babies because the developing human reproductive system may be exposed to DEHP when the metabolic pathways of detoxification are immature. Individuals that have among the highest exposures to DEHP are those undergoing certain medical treatments or procedures such as dialysis, exchange transfusion, ECMO, and cardiovascular surgery. Although intravenous (IV) exposure to DEHP through ECMO circuit or other intravenous routes exceeds recommended oral exposure limits, direct comparison between the two...
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