Also known as peel-apart tubing, paratubing entails a set of tubes bonded to remain bundled together until device assembly, patient care, or other pre-determined point of separation. Common medical devices incorporating these types of products are arterial drills, neurovascular devices, wound management procedural units, devices for laparoscopic and ophthalmic surgery, and biopsy devices.

For such devices, among the more sensitive risks is loss of suction during a procedure. Proper and consistent vacuum levels for fluid or mass removal are a critical factor in many application areas, and insufficient suction levels due to tubing line leaks can cause added discomfort for a patient, a longer procedural process, or both.

The other application factor of high importance is adequate and constant anesthetic or medicinal delivery. Disruption of an anesthetic agent can be painful and even dangerous for a patient, while insufficient medicinal supply caused by a tubing line leak could render a procedure ineffective or even harmful.

Considering all this, it is paramount a paratubing assembly-based solution has a validated, consistent manufacturing process behind a well-designed and robust product solution.

Mixing and Matching

Many medical devices must incorporate multiple, single-use tube lines, each of which supplies or removes a different fluid or gas. In addition, some of these devices also require a separate power line to provide a light source. A paratube makes it possible to combine these tubes into a single structure that is significantly easier for clinicians to manage.

The most modern paratubing solutions also can incorporate technologies that help ensure each tube line is connected to its corresponding device port. Unfortunately, connecting tubes to improper ports is a frighteningly frequent occurrence, threatening harm to patients and damaging professional reputations.

In this landscape, versioning is the surest path toward safety and success. To 0minimize risk during medical procedures requiring multiple lines to deliver fluids, gases, suction, and power to the same application space, a custom design may be recommended or even necessary to best ensure proper line connections. Colors, stripes, and individualized textures can be added to tubing lines, allowing them to be effectively and efficiently identified for accurate installation.

In addition, tubes can be composed of differing compounds engineered to accommodate the fluid, gas, or suction it provides, and tube ends can be separated to ensure efficient and secure bonding into connecting ports and luers. Some advanced tubing manufacturers can even produce configurations of up to eight tubes in eight distinct colors, bonded together in a single device solution.

Of course, matching the right tubes to the right ports isn’t the only challenge associated with paratubes. Several other pitfalls may arise far upstream from patient care—in the production and inspection processes.

Separation Anxiety

Paratube production is far from simple, presenting opportunities for several unacceptable issues to arise.

For starters, there’s a “peel strength Goldilocks Zone”—a sweet spot that must be maintained throughout the manufacturing process to ensure paratubing efficacy. On one end of the spectrum, to avoid premature separation, it is crucial tubes maintain a consistent bond, which typically requires a minimum 0.22 pounds of peel strength. On the other hand, bond strength must not surpass 1.5 pounds of peel strength at any spot; otherwise, mission-critical damage can occur to one or multiple tube lines. Like so many healthcare products, a mistake here can have a downstream impact on a supplier’s bottom lines, healthcare provider reputation, and, most importantly, patient health.

In addition to uniform peel consistency, another factor crucial to a robust, safe application design is maintaining tight tolerancing on both inner and outer tube diameters following their separation. Ensuring and inspecting dimensional stability for each bundled tube is challenging, and the right process controls must be employed to do this repeatably.

Notably, there are two distinct bonding methods—thermal and chemical—and various die configurations utilized to manufacture paratubes. Each presents its own obstacles that must be addressed early in the validation process. All setups have their own subsets of challenges that, worrisomely, often come to light only when the application moves to full-scale production—a result of inadequate steps toward ensuring product consistency at higher production line speeds.

Fortunately, some of the resulting product problems are instantly obvious. Among the more catastrophic issues with paratubing design occurs when the bond strength between two tubes goes beyond 1.5 pounds of pull force—an overshoot of paratubing’s Goldilocks Zone. In this scenario, significant portions of adjacent tube walls can stick to one another upon separation, causing improper mating connection. This insufficient fitting attachment adds to the risk of a fluid path leak or loss of suction in the application.

Other issues associated with excessive bond strength are less noticeable, but nonetheless, significant. A more subtle failure can occur if non-uniform bonding between tubes leads to smaller markings—so-called chatter marks—or void spaces on an individual tube. While large portions of a tube wall sticking are more recognizable and, therefore, more likely to be caught during inspection, smaller chatter marks are more difficult to identify but can lead to process leaks all the same—again due to insufficient solvent bonding to a fitting or luer.

Of course, the potential for in-the-field rejects also occurs when bond strength between tubes falls below 0.22 pounds of pull force. Under these circumstances, individual tubing lines can prematurely separate during transport, and are typically rejected by the clinician or surgeon prior to use—a reputation-damaging prospect. Further, if the product ends up being used, safety hazards in the operating room can arise as separated tubing lines can become tripping hazards or, even worse, get snagged during a procedure and inadvertently pulled from a patient.

All this outlines the importance of maintaining proper process controls and inline testing to ensure uniform, repeatable, and consistent peel strength, as well as inner and outer diameter tolerancing on individual tubing lines. Such rigorous process controls significantly improve the likelihood products received during design stages will be representative of those produced at high-speed, full-scale manufacturing.

A Cohesive Solution

Considering the wide-ranging variables inherent in paratubing production, no one-size-fits-all solution exists. However, ideal paratubing manufacturing conditions have several factors in common.

First and foremost, such solutions must maintain a consistent bond between 0.22 and 1.5 pounds of pull force—and be able to do so at high speeds. As with many medical device manufacturing scenarios, quality control becomes far more challenging as production scales up and speeds up.

For that reason, it is absolutely necessary for paratubing manufacturers to impose a strict policy of full validation for both bond strength and inner and outer dimension consistency. Anything short of such a rigid quality control protocol fails to ensure design stage paratubes match those produced in full-scale, high-speed production.

Finally, the most versatile of paratube suppliers will be able to recommend and produce tube compounds suitable for various purposes. For example, TekniPlex Healthcare recently helped a leading breast cancer biopsy device maker switch to a more application-friendly PVC compound. Often, such appropriate alterations improve patient outcomes and reduce pre-operative rejects, even while reducing overall manufacturing costs. 

Article Source: MDDI