Phthalates/DEHP in PVC medical devices

What are phthalates?
Phthalates are chemicals that are added to PVC (a type of plastic) to make it softer and more flexible. Phthalates are the most widely used plasticisers in the world. In medical devices the most commonly used phthalate is DEHP (di(2-ethylhexyl) phthalate). Phthalates have been in medical use since 1955.

Which medical devices contain DEHP?
Devices that may contain DEHP-plasticised PVC include:

• intravenous (IV) bags and tubing
• umbilical artery catheters
• blood bags and infusion tubing
• enteral nutrition feeding bags
• nasogastric tubes
• peritoneal dialysis bags and tubing
• tubing used in cardiopulmonary bypass (CPB) procedures
• tubing used in extracorporeal membrane oxygenation (ECMO)
• tubing used during hemodialysis.

Why is DEHP used in medical devices?
DEHP softens PVC which makes tubes and catheters softer and more flexible. This can make medical devices easier to use, less likely to cause damage to tissue and more comfortable for the patient.

Why is there concern over DEHP in medical devices?
DEHP can leach from PVC devices into fatty solutions like blood or nutrition formulas. At certain doses, DEHP has been shown to cause reproductive birth defects and infertility in animals.

Are medical devices that contain DEHP safe?
In 2002 the EU Scientific Committee on Medicinal Products and Medical Devices (SCMPMD) published an opinion (external link) on DEHP in medical devices. It was the committee’s view that overall the advantages of using DEHP outweighed the disadvantages. This opinion was based on the absence of reports of adverse effects in humans (even in neonates or other groups of patients with relatively high levels of exposure) and on the benefits that DEHP brought as an efficient plasticiser. In addition it was the committee’s view that safety data on most of the alternatives to DEHP-plasticised PVC were very limited and that these materials could pose an unknown (and thus possibly higher) risk.

On 15 October 2007 the EU Scientific Committee on Emerging and Newly-Identified Health Risks (SCENIHR) published it’s report on “the safety of medical devices containing DEHP-plasticized PVC or other plasticizers on neonates and other groups possibly at risk” 

› The safety of medical devices containing DEHP-plasticized PVC or other plasticizers on neonates and other groups possibly at risk (external link)

The SCENIHR report takes into account new scientific data and the committee considers that despite a lack of clinical evidence for harmful effects on humans, the high exposure of patients to phthalates during medical treatment is a cause for concern.

The MHRA has reviewed the SCENIHR report and has concluded that:

• there is no new evidence to suggest that medical devices plasticised with DEHP present an unacceptable health risk to humans. In particular, there is no proven effect of exposure to DEHP on male reproductive health – the adverse effect of concern in the SCENIHR report
• medical devices containing DEHP-plasticised PVC have important clinical benefits
• in view of the proven clinical benefits of PVC medical devices plasticised with DEHP it would be premature to recommend a change to other plasticisers.
  

DEHP and the Medical Devices Directive
The placing on the market of medical devices is controlled through the Medical Devices Directive. This requires that the manufacturer should eliminate any risks where feasible or reduce them as far as possible in line with the generally acknowledged state of the art. The acceptability of any residual risks is then determined by the level of benefits that the product brings.

It is important to recognise that the availability of an alternative medical device that is free of DEHP does not necessarily mean that it can be substituted in a particular clinical procedure without compromising the safety of the patient.  A number of device manufacturers have pointed out that the physical properties considered essential for some products used in highly demanding situations (for example in some life-saving procedures on premature babies) cannot be achieved using the currently available alternatives to DEHP-plasticised PVC.

The CE-marking of a medical device is not an indication that the device is the most appropriate option for a particular purpose; the choice of device is a matter for clinical judgement.  CE-marking is an indication that the device meets the Essential Requirements of the Medical Devices Directive.  These Essential Requirements oblige device manufacturers to ensure that any risk, such as that arising from exposure to DEHP, is outweighed by the anticipated benefits to the patient. The supply of DEHP-plasticised PVC medical devices  is thus in line with the regulations in circumstances where the clinical benefits arising from the use of the material outweigh the possible risks and cannot be achieved by other means.

In relation to the regulation of DEHP in medical devices, the MHRA’s position is that no additional regulatory measures are necessary to facilitate the phasing out of DEHP-plasticised PVC in medical devices. The provisions of the Medical Devices Directive are adequate to ensure that any material known to present a toxic hazard is replaced as soon as alternatives with a more positive risk-to-benefit balance are available. Meanwhile, recognising that the undesirable characteristics of DEHP-plasticised PVC represent only one facet of a complex risk-to-benefit equation, it appears at present that this material is essential in some medical devices used in critical circumstances. In some situations, coatings that lead to a significant reduction in DEHP-exposure can improve the total risk-to-benefit ratio. Where DEHP is not essential, the manufacturer’s risk assessment (required by the Medical Devices Directive) should lead to the conclusion that alternative materials that do not result in exposure to DEHP should be used.