Impact of Device Standards on Perfusion Practice.

Most of us are busy doing the noble deeds of patient care and some of us can barely catch enough sleep to worry about device standards. When we put together all the components and make it into a system, we take it for granted that they will work efficiently, effectively, and safely for the duration of use for which it is intended. This fact is pretty amazing considering that various components in your system likely came from different manufacturers and have never been tested as a system. Only recently, the Association for Advancement of Medical Instrumentation (AAMI) and the International Organization for Standards (ISO) have started to make inroads to established system standards. So why should a clinician be concerned about standards? More important, how would standards affect a clinician’s application and practice? There are rhetorical questions a clinician should ask such as, “Do the manufacturers live up to their claims? Do their claims live up to the user’s expectations? Do their claims live up to the safety standards intended to deliver quality care to the cardiac patient?” Also, “Do the testing methods described in device standards provide information pertinent to clinical practice?” This communication focuses on the latter question. AAMI and ISO are two major standards organizations responsible for authoring testing standards, quality management, sterilization, and labeling appropriately to assure safe use and optimal performance of the products used for the cardiac patient. AAMI is a national member of ISO. ISO writes international standards for the world. Both standards are referenced by the US Food and Drug Administration, and ISO standards are referenced by respective regulatory agencies around the world such as the German Institute for Standardization (DIN) and the Korea Agency for Technology and Standards (KATS). In reality, most documents on perfusion devices were generated by working group four (WG-4) in AAMI and promoted and supported by ISO around the world. ISO and the US Food and Drug Administration (FDA) have taken more active roles recently. Representation of the organizations is well supported by AmSECT since 1980. A period of representation hiatus occurred from 1990 to 1995. Because of the amount of resources required to reach consensus around the world, many of the standards are just scratching the surface of what is adequate for the practicing perfusionist. For example, the standard for an oxygenator designated as a “blood gas exchanger” is AAMI/ISO document 7199. An important document that accompanies an oxygenator is the Directions for Use (DFU). Very important information provided for the user is the oxygenation performance at 2, 4, or 6 L flow per minute expressed in a graph format indicating total oxygen transfer. The test conditions in vitro (bench) are 12 ± 2 g/dl of hemoglobin 37 C and venous oxygen saturation of 65% ± 5%. These are the AAMI/ISO-specified testing conditions. It is interesting that manufacturers compare the gas exchange performances of their oxygenators against competitors citing the data were collected under AAMI/ISO testing conditions. All oxygenators would have the same transfer performances if AAMI/ISO standards were strictly controlled. All oxygenators must be able to oxygenate desaturated blood (same inlet conditions) to 99% or 100% on a single pass at 37 C. Manufacturers reference the testing method in the AAMI/ISO 7199 document when submitting their data to the FDA for approval of a product. However, there are differences in gas exchange performances of oxygenators. Maximum oxygen transfer varies from 400 cc per minute to >600 mL per minute relative to brands. If the inlet condition (venous saturation) is lower, differences in performance will be evident from brand to brand and even within the same brand. Received for publication October 23, 2014; accepted November 4, 2014. Address correspondence to: Richard Chan, CCP (Emeritus), Oyster Bay, NY. E-mail: [email protected] The author has stated that he has no material, financial, or other relationship with any healthcare-related business or other entity whose products or services are discussed in this paper.