Tetherless Monitor Continuously Measures Hemoglobin Concentration

A novel wearable device enables non-invasive monitoring of more than 10 parameters, including continuous total hemoglobin concentration (SpHb).

The Masimo (Irvine, CA, USA) Radius-7 with Root is a lightweight device that provides rainbow SET noninvasive sensor technology, which uses more than seven wavelengths of light to acquire blood constituent data based on light absorption. Indices measured include blood oxygen saturation (SpO2), pulse rate, and perfusion index (PI). Advanced signal processing algorithms and unique adaptive filters work together to isolate, identify and quantify various hemoglobin species, including SpHb.


The Radius-7 with Root attaches to the arm, allowing untethered monitoring whether a patient is in or out of bed, thus reducing the need for nursing assistance to disconnect from or reconnect to a bedside monitor. The Radius-7 communicates to Root at the bedside, and thereon to the Masimo Patient SafetyNet in order to alert clinicians of critical changes in oxygen saturation, pulse rate, respiration, and hemoglobin, among other parameters. Each Radius-7 comes with two “hot-swappable” rechargeable battery modules, each with a battery life of 12 hours, to minimize monitoring interruption.

“Never before could patients be monitored for such key parameters as continuous SpHb, which can help clinicians make more timely and informed blood management decisions, while patients are fully mobile,” said Joe Kiani, founder and CEO of Masimo. “Root with Radius-7 with rainbow SET, coupled with Patient SafetyNet for mobile clinician notification, is now an even more versatile and powerful monitoring system, all while promoting freedom of patient movement and quicker recovery times.”

“We are monitoring SpHb for selected postsurgical patients, which can be extremely beneficial because it can provide insight into hemoglobin trends between invasive blood samplings,” said professor of anesthesiology and intensive care Christer Svensen, MD, of Karolinska Institute (Stockholm, Sweden). “Such insight may lead clinicians to confirm trends by performing blood draws sooner than they might otherwise have done, which may then suggest the need to intervene.”

SpHb monitoring may provide insight to the directional trend of hemoglobin between invasive blood samplings. For example, when SpHb trend is stable, and the clinician may otherwise think hemoglobin is decreasing; when SpHb trend is rising, and the clinician may otherwise think hemoglobin is not rising fast enough; or when the SpHb trend is decreasing, and the clinician may otherwise think hemoglobin is stable.

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