Radiation resistant compound helps childbirth

When Prism Enterprises developed its new one-piece vacuum-assisted delivery system it worked with RTP Company to select thermoplastic materials that could be incorporated into the product.

In the past, when complications arose during childbirth, a forceps was used to assist in extracting the foetus, speeding delivery and reducing the duration of dangerous stress.

Today, forceps have been replaced with vacuum-assisted delivery systems.

When Prism Enterprises, a pioneer in vacuum-assisted technology, was developeing its new one-piece integrated unit called the MityOne it worked with RTP Company to select thermoplastic materials that could be successfully incorporated into the product.

Vacuum-assisted delivery systems employ a flexible shaft that allows precise positioning of a flexible suction cup on the baby's head.

A pump then generates negative pressure to allow the clinician to gently pull and assist with maternal efforts during vaginal operative deliveries.

A vacuum-assisted delivery is traditionally a two-person operation - a physician places the extraction device and a nurse controls the pump - and one that demands exacting teamwork and precise communication during a sometimes frenzied event.

To eliminate the need for extra medical personnel, Prism Enterprises developed the MityOne which provides full control to a single operator.

Because the pump is sterilised prior to use, the materials chosen had to be resistant to gamma radiation.

A sturdy, coloured material was needed for the pump's handle, and the shaft required a precise balance of strength and flexibility.

Additionally, healthcare industry quality procedures dictated that the materials be verifiably consistent throughout production.

An RTP 100 Series polypropylene compound was selected for the shaft.

With a flexural modulus of 1102MPa and tensile elongation of more than 10%, the material yields what Frances Menard, Prism's Director of Marketing for Labour and Delivery, calls: "an ideally balanced, semi-rigid part".

Tensile strength of 31MPa allows the shaft to withstand the pulling forces generated, while the low modulus permits pliancy through a wide positioning range.

RTP Company engineers included a stabilisation package to enhance radiation resistance.

An RTP 600 Series ABS compound allows the handle to withstand the rigours of delivery room use.

Menard credits the part's rich, purple colour as providing "both good visibility for the operator and nice aesthetics; the smooth finish compliments the ergonomic design".

Moreover, Menard stressed mechanical performance by saying, "The material and the design function well together.

We've not seen one instance of failure and this is an area where failure would be unacceptable".

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