Medical tubing is tubing that meets medical industry requirements and standards for a variety of medical or pharmaceutical related applications. Medical tubing is used for fluid management and drainage as well as with anesthesiology and respiratory equipment, IVs, catheters, peristaltic pumps, and biopharmaceutical laboratory equipment.

Standards and Certifications

What sets medical tubing apart from other types of tubing is its designation for medical applications. This designation typically comes through standards or certifications which dictate material and specification requirements for tubes. These requirements are in place to ensure that the equipment used for patient care and drug manufacturing is reliable and safe.

Good Manufacturing Practice (GMP) and Current Good Manufacturing Practice (cGMP) are production and testing practices that help ensure product quality. The U.S. and many other countries have legislation in place that requires medical and pharmaceutical companies to follow GMP procedures. The exact procedures vary by country, but all are in place with the intent to keep patients healthy and ensure the production of quality drugs and medicine. Tubing which meets all the required specifications may still not be approved medical applications if it was not produced according to GMP guidelines.

ISO 10993 is a series of standards set by the International Standards Organization (ISO) which evaluates the biocompatibility of medical devices prior to a clinical trial or study.

USP Class VI is a certification put in place by the U.S. Pharmacopeial Convention (USP) which judges the material suitability and compatibility of medical grade devices. The standard includes tests for toxicity, biochemical compatibility, leaching, and inertness. USP Class VI is typically a base requirement for all medical grade devices. 

The Food and Drug Administration (FDA) also has standards which (depending on the specific application) may be required for certain types of medical tubing.

Materials

There are a broad range of materials used to construct medical tubing. Material type determines important performance properties for medical tubes, such as abrasion resistance, hardness, flexibility, and durability. Most medical grade tubing is made of some type of plastic or rubber material, although certain applications may require metal tubes. For more information on the qualities of different types of materials, visit the Plastic Tubing, Rubber Tubing, and Metal Tubing specification guides.

Material selection is crucial for medical applications, since incompatible materials can cause a number of problems. For example, incompatible tube materials can chemically alter drugs and medicines or cause them to bind to the tube wall, resulting in failed delivery to the patient. In addition, tubes that are radiopaque (x-ray absorbing) cannot be in or on patients receiving x-ray scans, as it would result in an unacceptable image. 

Sizing

Sizes for medical tubing are based on the outside diameter, which defines the entire span of the tubing cross section. Other dimensions for tube sizing are inner diameter, which defines the span of the open area inside the tube, and wall thickness, which defines the actual width or thickness of the tube itself. In addition, tubes come in standard lengths which denote the continuous span of the tube from end to end. Dimensions for tubing can be specified in both English units (inches) and Metric units (millimeters). Proper sizing is necessary in order to fit tubes into proper connections and equipment, and also has an influence on performance properties such as flow rate.

Performance Specifications

Medical tubing performance is rated based on a number of performance specifications given by the product manufacturers.

• Pressure rating defines the minimum or maximum pressures the tube is designed to withstand, measured in pounds per square inch (psi).
• Maximum vacuum defines the maximum vacuum pressure that can be created in the tube, most frequently given in inches or millimeters of mercury, referenced below one standard atmosphere.
• Minimum bend radius is a rating based on the acceptable amount of deformation the tubing cross-section can undergo, typically given in inches or millimeters. The smaller the minimum bend radius, the higher the tube flexibility. Flexing the tube too far can cause kinking or permanent deformation, which can be especially dangerous in medical applications.
• Temperature range defines the full range of ambient temperatures that the tubing is designed to operate within.

Features

Medical tubing may require many different features depending on the specific application. Most notable is opacity, which defines the ability to see-through the tube. Clear tubing is important for tubes used to handle fluid delivery in order to track fluid movement and account for possible air bubbles in the system. Other features include sterilizability, the ability to coil the tubing for storage or transport, and spark or static resistance. 

References

Medical Grade Tubing - U.S. Plastic Corporation

Medical Tubing - PolyOne™

Image Credits:

NewAge Industries, Inc. |  Masterbond