PVC & DEHP
The chemical compound DEHP, Di(2-ethylhexyl) phthalate, is contained in many of the common plastic products found in health care settings. It is in a category of toxic chemicals known as pthalates, which are commonly added to polyvinyl chloride (PVC) plastic to make the plastic product flexible and strong. It allows the otherwise stiff PVC to be molded into a variety of products such as IV tubing, IV bags, and feeding tubes. By weight, DEHP comprise 20- 40% of the PVC products on average. There is new evidence regarding the human toxicity associated with exposure to DEHP that should help to inform our product selection in the health care setting.
"DEHP does not bind with plastic, so it can leak out of PVC medical products during medical procedures, or when PVC objects such as toys are chewed. Everyone is exposed to DEHP through off-gassing from vinyl products in the home and workplace, as well as from industrial emissions. However, some infants and especially pre-term neonates are receiving, in some cases, megadoses of DEHP. Neonatal nurses should know what they can do to protect their tiny patients from the potentially harmful effect of DEHP. The multiple and relatively high exposures that may occur in neonatal intensive care units (NICUs) are significant. Many of these babies are exposed during blood and other intravenous infusions, respiratory therapy, enteral feedings and extra corporeal membrane oxygenation (ECMO)" (quote from Ann Melamed in The American Nurse, December 2000).
The National Toxicology Program's Expert Panel who reviewed DEHP studies only looked at reproductive and developmental effects. Based on animal studies, there are concerns that there may also be effects on the liver, kidneys, and lungs, as well as effects on heart rate and blood pressure.
So how does the chemical DEHP create a risk to humans when it is in PVC medical devices? When it is in PVC, it is not actually bound chemically. It can therefore escape the PVC product under certain conditions such as when the product is heated, or when the medical device contacts fluids—such as the fluids that would be in an IV or blood bag. DEHP migrates into a variety of fluids including blood, plasma, and total parenteral and enteral nutrition solutions. During medical interventions that require long-term IV interaction such as hemodialysis or ECMO, DEHP exposure is significantly enhanced. Pediatric exposures are of the greatest concern. Sick newborns and infants face the greatest risk of exposure from medical interventions and may also be the most vulnerable to the toxic effects of DEHP because of their stage in human development. During critical stages of development, preterm babies, and neonates may be exposed to DEHP, a reproductive and developmental toxicant. This occurs because of the ubiquitous presence of DEHP in their environment. The multiple and relatively high exposures that can occur in the NICU are potentially at or in excess of levels known to cause adverse health effects in relevant animal studies.
"Since DEHP releases to vinyl products are not easily controlled, prevention should be the primary management option" (Rossi, 2000). To ensure that our patients are not exposed to DEHP, we will have to demand DEHP-free health care products, particularly in those settings where our smallest and most vulnerable patients are cared for. Using PVC-free products virtually assures that the product will be DEHP-free because the other plastics rarely add DEHP. "In addition, PVC-free products avoid the lifecycle hazards of vinyl, including the use of a known carcinogen to manufacture vinyl (vinyl chloride monomer) and the downstream formation of dioxin when vinyl is burned in a medical waste incinerator" (Rossi, 2000; Thornton et al., 1996; Wagner and Green, 1993).
PVC is the most widely used plastic in medical products. It accounted for 27% of all plastic used in durable and disposable medical products in the United States in 1996 (Schettler et al., 2000).
Approximately 445 million pounds of PVC were consumed in the manufacture of intravenous (IV) and blood bags, tubing, examination gloves, medical trays, catheters, and testing and diagnostic equipment in 1996. Tubing, IV and blood bags, and gloves are the primary end-uses for PVC in disposable medical products. Both patients’ health and safety, as well as the public’s health, are of concern regarding PVC.
In January 2002, the Health Canada Expert Advisory Panel recommended that health care providers not use DEHP-containing devices in the treatment of pregnant women, breastfeeding mothers, infants, males before puberty, and patients undergoing cardiac bypass, hemodialysis, or heart transplant surgery. They recommended the alternative measures be introduced "as quickly as possible."
From 'Environmental Health in the Healthcare Setting,' by Barbara Sattler, DrPH, RN