SF | PATIENT SAFETY
October 2021 | Vol. 21 No. 10 Photo credit: Shutterstock.com
www.medicalacademic.co.za
The PVC debate continues
This article was independently sourced by Specialist Forum.
Polyvinyl chloride (PVC) has been used for decades in the manufacturing of plastic products, including medical devices. Current evidence shows that the use of PVC has significant health implications at all stages in the lifecycle.
I
n 2020, the European Commission commissioned a study entitled The use of PVC in the context of a nontoxic environment. It aims to identify and describe uncertainties (particularly from chemicals perspective), about PVC production, recovery, and end of life treatment, and to help assess the role of PVC in the context of the European Green Deal and the Circular Economic Action Plan. The final report will be released next month.
Why is PVC a ‘problematic material’? PVC is a soft, flexible plastic used to make clear plastic food wrapping, cooking oil bottles, teething rings, children’s and pets’ toys, and blister packaging for myriad consumer products. It is commonly used as the sheathing material for computer cables, to make plastic pipes and parts for plumbing, and in garden hoses. See Figure 1 on page 46 for the use of PVC in a hospital setting. Phthalates are used to increase the flexibility and durability of PVC products. Diethylhexyl phthalate (DEHP) is the most commonly used plasticiser for PVC. Soft PVC can consist of a high percentage of DEHP (up to 40%). DEHP is not chemically bound to plastic materials and can therefore leach to into body fluids via ingestion, inhalation, dermal absorption, or intravenous route. Medical procedures with potential for high exposure to EDCs include: » Exchange transfusion of blood in neonates » Extracorporeal membrane oxygenation treatment of neonates and of adults » Total parenteral nutrition in neonates
» Haemodialysis in peripubertal males » Haemodialysis in pregnant or lactating women » Enteral nutrition in neonates and adults » Heart transplantation or coronary artery bypass graft surgery » Massive blood transfusion of red blood cells and plasma.
cytosine residues in DNA, post-translational modification of histones and altered microRNA expression. These changes may lead to transgenerational effects on numerous organs and organ systems and are thought to be tissue-specific as well as dose-dependent.
Impact of long-term exposure
Alternative plasticisers (PVC-free vs DEHP-free)
Children – especially those treated in paediatric intensive care units – are at high risk of exposure due to their low body weights and their underdeveloped organs. Research shows that such exposures may increase children’s susceptibility to several non-communicable diseases in adult life. EDCs are associated with diabetes, obesity, metabolic disorders, thyroid homeostasis, and an increases risk of hormone-sensitive cancers. They also have deleterious effects on male and female reproductive health. In utero exposure to several EDCs was found to influence foetal growth and birth weight. Exposure to EDCs during the prenatal and perinatal period has been thought to influence the timing of puberty as well. Several studies evaluating the neurological development of children have shown associations of prenatal EDC exposure with adverse cognitive and behavioural outcomes. Furthermore, exposure has been associated with an increased risk of allergic diseases such as eczema and asthma. Emerging evidence shows that EDC exposure also has epigenetic and transgenerational effects. EDCs have been shown to modify gene expression without mutating DNA, which is known as epigenetic change. The known possible mechanisms of epigenetic changes include methylation of
With growing concerns about DEHP toxicity, some product manufacturers are substituting alternative plasticisers for DEHP in various medical products rather than switching to alternative, non-PVC polymers that do not require plasticisers at all. The toxicity of other plasticisers and their tendency to leach out of the PVC product can vary from DEHP. Some are less hazardous and have no-effect levels higher than DEHP. However, many have not been as extensively studied as DEHP and related phthalates, particularly with regard to reproductive toxicity and endocrine disruption. Four of these alternative PVC plasticisers (1,2-cyclohexane dicarboxylic acid diisononyl ester, butyryl trihexyl citrate, tri-[2-ethylhexyl] trimellitate, dioctyl terephthalate) are included in the European Pharmacopoeia, in order to provide manufacturers with alternatives to DEHP in medical applications. In 2007, Health Care Without Harm (HCWH) Europe documented hospitals across Europe that had begun phasing out PVC medical devices to protect patients from DEHP and other alternative plasticisers. Among the alternative plastics that can be used for various medical products and devices are polyolefins, including polyethylene and
45
