For surgical procedures requiring irrigation, pumps are one of the more significant medical device components, and pump selection is paramount to operational success. Watson-Marlow Fluid Technology Group (WMFTG) specializes in fluid management, offering over 60 years’ experience in high-quality components for medical devices. MDB spoke to Rodd Turnquist, National Sales Manager US, OEM Division, WMFTG, to find out more about selecting the best pumps for medical devices and accelerating time to market.

MDB: Why are peristaltic pumps the best choice for medical devices?

Rodd Turnquist: Peristaltic pumps have several operational advantages for surgical devices over traditional positive displacement pump designs. Fluid is fully contained within the tube, allowing straightforward setup with single-use, presterilized tubing that gives total hygiene and guaranteed integrity, removing risk of cross contamination — essential in a sterile environment.

Rodd Turnquist
Rodd Turnquist

MDB: Can you elaborate on how these pumps work?

Turnquist: Peristaltic pumps are a type of positive displacement pump. The pumps use the principle of peristalsis as the basis for their design. Peristalsis, in a biological sense, is a series of muscle contractions that moves food to different parts along the digestive system. Rollers or shoes in a peristaltic pump compress the tube or hose as they rotate, creating a vacuum, which draws fluid through the tube.

Nothing but the pump tube or hose touches the fluid, eliminating the risk of the pump contaminating the fluid, or the fluid contaminating the pump. The fluid is drawn into a pump tube, trapped by the pumphead roller, and expelled when the next roller passes over the tube. As the rollers rotate, a vacuum is formed in the tube, pulling in more fluid for the next roller pass.

The complete closure of the tube when it is occluded (squeezed) between the roller and the track, gives the pump its positive displacement action, preventing backflow and eliminating the need for check-valves when the pump is not running.

MDB: What are the advantages of WMFTG pumps for use in minimally invasive surgery?

Turnquist: Precision instruments have facilitated the rise of minimally invasive surgery, transforming patient outcomes. Surgical ablation is used in many of these devices, requiring precise temperature control to prevent scarring and unwanted tissue damage.

The 400RXMD pump was purpose-designed to deliver a range of precise pressure settings with a simple, robust design. Innovative safety features include a new profiled tube holder that ensures correct tube positioning, minimizing human error and enabling rapid, trouble-free tube loading.

Understanding the changing needs of the industry alongside extensive research and development ensures that the pump meets the demands of surgical ablation applications.

MDB: How does the 400RXMD provide these benefits?

Turnquist: The ability to factory-set the pump means that the pressure/flow profile can be fine-tuned to the requirements of each application. The pump delivers flows up to 500 ml/min at pressures exceeding 6 bar. Automated tube clamps and simple lever loading enable simple tube-set changeover.

An innovative mechanism has also been introduced giving improved flow accuracy, while a new tube holder ensures the tube locates in the right position every time the safety lid is closed, providing rapid, trouble-free tube loading. This minimizes the risk of human errors and thus safeguards the process.

This simple, robust and unique pump solution is great news for equipment that uses the technique of radio frequency ablation, where the pump is part of a larger system that includes an RF generator, and a catheter or needle. The RF energy is applied to destroy unwanted tissue by controlled internal cellular heating, avoiding the need for invasive surgery.

The 400RXMD pumps cooling fluid to provide precise temperature control, which produces a more effective treatment and prevents scarring. The cooling fluid helps concentrate the RF energy on the target area, which is particularly important when ablating large volumes of tissue such as in the treatment of cancer. This technique is becoming widespread in the treatment of cardiac arrhythmia, as well as cancer treatment and many other surgical procedures.

As the definitive OEM peristaltic pump for use in surgical ablation systems, this pump specifically meets the needs of catheter, cannula, or needle-cooling applications. We test every pump to each customer’s specific test protocol.

MDB: What were the factors driving the launch of this series now?

Turnquist: Although Watson-Marlow’s existing RX models have been very successful in the medical sector for the past 15 years, the determination of the company to evolve its products in line with changing market demands and trends, is exemplified by the launch of 400RXMD (the ‘MD’ in the product name denotes ‘medical device’). Underpinning the product is extensive research with industry experts to ensure it meets the needs of surgical ablation applications.

Unique performance and robust modern design were among the fundamental basics supporting the RX pump’s success, and these features have been retained. However, there is a multitude of customer-identified improvements introduced in the new RXMD family. For instance, a range of precise pressure settings to tailor products for specific customer applications. The 400RXMD pumps will be delivered to a customer with pre-set pressure performance for effective catheter ablation.

MDB: Why is customization important?

Turnquist: Customization plays an important role to optimize functionality, and our engineers are uniquely placed to adapt each pump’s design. This includes compatibility with custom tubing types and sizes, integration into the device, triboelectric effect reduction, and branding.

Medical device OEMs often need some level of customization beyond the standard off-the-shelf products. We have development services in place to assist customers in optimizing the functionality and performance of their overall system.

We can start with the rapid delivery of samples from our wide range of standard products. Over the arc of a customer’s project, we can create a complete pump, motor, and drive sub-assembly that is tested and ready to install in their equipment.

MDB: What is the advantage of working with a pump specialist throughout the design process?

Turnquist: All product needs are considered from the start: performance, functionality, size, ease of incorporation, and final appearance. This helps accelerate the process, increasing potential ROI. It also means engineers are on hand to support product testing, quality assurance, and regulatory compliance.

MDB: How does WMFTG stand out?

Turnquist: Our customers prioritize delivering high-quality devices quickly to maximize return on investment. We understand the industry and can accelerate time to market by choosing the best pump and optimizing it for each application, focus.ing on usability and fail-safe tubing interchange. WMFTG pumps deliver repeatable, accurate performance, providing confidence in reliability.

Another advantage is our breadth of experience. We are not just pump experts but also provide the correct type of high-quality tubing for every application that can be easily exchanged or cleaned. We design our pumps to optimize useability, making tubing interchange as easy as possible and fail-safe for operators.

Our experience helps manufacturers meet U.S. FDA or European Medical Device regulations, or meet the ISO 13485 medical device standard. Based on a strong foundation of ISO9001: 2015, our quality systems have dependable change management processes and product traceability. These, along with a comprehensive design process, help customers maintain regulatory documentation such as design history files and device master records.


Medical Design Briefs Magazine

This article first appeared in the August, 2021 issue of Medical Design Briefs Magazine.

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