Medical Device Link.

Originally Published MX November/December 2002

COVER STORY

Masimo Corp. may not have anticipated finding so much of it in the marketplace, but the company knows a little something about interference. Finding ways of dealing with it is the basis of the company's key technology.

Invented by company founders Joe E. Kiani and Mohamed Diab in 1989, Masimo's signal extraction technology (SET) is a method of acquiring, processing, and reporting patient physiological data. It combines innovative sensor technologies and proprietary signal processing algorithms with adaptive filters that work in real time to ensure accurate readings through all patient conditions, including mo-tion. Masimo was the first company to solve the problem of motion-related interference, and it has received numerous awards and pat-ents for its contributions to the field of non- invasive patient monitoring.

The Radical SET pulse oximeter, manufactured and sold by Masimo Corp. (Irvine, CA), was the winner of a silver award in the 2001 Medical Design Excellence Awards competition.

Applied to pulse oximetry, SET's adaptive filter technology separates the arterial signal from nonarterial noise, thereby eliminating interference resulting from motion artifacts, low peripheral perfusion, and weak signal-to-noise situations. To process the incoming signal, Masimo SET pulse oximeters make use of the conventional red-over-infrared algorithm, but also employ parallel processing using four additional algorithms—including adaptive filter-based discrete saturation transform (DST), fast saturation transform (FST), and SST—all patented by Masimo.

In operation, the sensor transmits patient data to the monitor, where it is presented to the set of algorithms. Each algorithm's unique strengths are leveraged to ensure accurate readings of the patient's arterial oxygen saturation and pulse rate.

Masimo began licensing SET to other manufacturers in 1992. According to the company, more than 60% of the world's pulse oximetry manufacturers have licensed the technology for inclusion in their own systems. Today, the technology is incorporated into nearly 100 devices, from sophisticated patient monitors, infant incubators, and defibrillators to Masimo's own Radical pulse oximeter (see Figure).

In 1998, Masimo's technology was unveiled in the United States with the introduction of branded products by two of the company's oldest partners: a patient monitor by Datascope and a stand-alone pulse oximeter by Ivy Biomedical, both incorporating Masimo SET pulse oximetry.

And that, says the company, is when the real interference started.

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