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PVC – A Material of
Choice for Life-Saving Devices
Because of plastic’s smoothness and
particularly its durability, the shift from traditional
materials made treatments less painful and far safer for
patients. The new plastic-based devices enabled doctors
and nurses to improve patient care. It is doubtful,
therefore, that the call for plastic-free healthcare
recently proposed by NGO Healthcare Without Harm will
find support among patients or healthcare professionals.
The first breakthrough came with the
introduction of the blood bag. It was developed as a
prototype in 1947, tested clinically at Harvard in the
1950s, and used experimentally in the Korean War, where
it showed its worth. The PVC-based bag replaced fragile
glass bottles and proved superior in preventing
contamination and breakage. As the robust bag could
withstand being dropped from the air, it helped save the
lives of thousands of soldiers.
Further, the PVC blood bag enabled a
revolution in blood collection and preparation. The PVC
bag could withstand the high g-force of the centrifuge
that separates blood into plasma, red blood cells, and
platelet concentrates. This enabled the safe and easy
preparation of multiple blood components from a single
unit of whole blood.
The material’s robustness continues to
be a key advantage. In various parts of Africa, for
example, drones deliver blood much faster than would be
possible by land transport. Instead of a fivehour
round-trip drive to a hospital, the average time for a
drone delivery is 30 minutes.
Unique properties of PVC
Since the 1960s, the medical
applications of PVC have broadened well beyond blood
bags. PVC formulations can cover a range of properties,
spanning soft, flexible rubber to rigid engineering
thermoplastics. As a consequence, PVC is used to make
tubing, oxygen masks, containers for IV and dialysis
fluids, IV sets, nasal cannulas, overshoes, examination
and surgical gloves, blood vessels for artificial
kidneys, blister packaging, mattress covers, training
manikins, and many other products.
PVC's range of properties, safety, and
low cost has made it a goto material for a variety of
medical devices.
Recently, PVC has shown its value in the
fight against COVID-19, both with traditional medical
devices and innovative solutions. PVC’s durability,
weather resistance, and fire retardancy make it the
perfect material for temporary testing and vaccination
centers. PVC-based inflatable hoods for ventilators,
gowns, gloves, and visors help protect healthcare
workers from the virus.
PVC owes its success to a number of
factors. If transparency and anti-kinking properties are
needed, PVC is the only choice. Its versatility and ease
of processing allow for the manufacturing of
mono-material devices that consist of both soft and
rigid parts. This property is essential to recycling, as
we will see later in this article.
PVC can be used in a range of
temperatures and it retains flexibility, strength, and
durability at low temperatures.
PVC formulations exhibit excellent
strength and toughness. For example, vinyl gloves
possess very good resistance to tearing to protect both
doctors and patients and help prevent the spread of
infection, germs, and disease. They offer a viable
alternative solution to latex allergies.
PVC is characterized by high
biocompatibility and hemocompatibility, and this can be
increased further by appropriate surface modification.
Materials used in medical applications
must be capable of accepting or conveying a variety of
liquids without themselves undergoing any significant
changes in composition or properties. PVC has excellent
chemical stability and thereby meets these demands.
PVC is compatible with virtually all
pharmaceutical products in healthcare facilities today.
It also has excellent water and chemical resistance,
helping to keep solutions sterile.
Plasticized, flexible PVC medical
devices can be easily sterilized via steam, autoclave,
radiation (electron beam or gamma rays) or ethylene
oxide methods, while maintaining key properties such as
flexibility and resistance to tears, scratches, and
kinks. Rigid unplasticized PVC medical devices can be
sterilized using low temperature steam (60 to 80°C),
radiation, or ethylene oxide. |
