Acoustic Sensors Continuously Monitor Respiration Rate

An innovative adhesive sensor with an integrated acoustic transducer noninvasively measures respiration rate.

The Masimo (Irvine, CA, USA) RAS-45 acoustic respiration sensor for rainbow acoustic monitoring (RAM) takes advantage of Masimo signal extraction technology (SET) to separate and process the respiratory signal in order to display the acoustic respiration rate (RRa). Similar to the company’s RAS-125c acoustic sensor, it operates with Masimo MX atechnology boards to display results in an acoustic respiration waveform. The sensor is affixed to the patient’s neck with a small, flexible, and transparent adhesive patch that facilitates placement.


Both the RAS-45 and the RAS-125c maintain the same performance parameters, range, and accuracy specifications, offering a breakthrough in patient safety for post-surgical patients and for monitoring procedures requiring conscious sedation by facilitating earlier detection of respiratory compromise and patient distress. Both sensors have received the European Community CE mark of approval, and are intended for single-use in adult and pediatric patients who weigh more than 10 kg.

“RAM harnesses the power of our breakthrough signal processing technology, using Masimo SET and rainbow technologies, and applies those achievements to a respiratory measurement derived from the sound of breathing,” said Joe Kiani, Founder and CEO of Masimo. “Studies have found that RAM RRa is more sensitive to detecting respiratory pause, and yet easier for clinicians and patients to use.”

Respiration rate is a critical vital sign that provides early identification of respiratory compromise and patient distress, and is especially important for post-surgical patients receiving patient-controlled analgesia (PCA) for pain management, as the sedation can induce respiratory depression and place patients at considerable risk of serious injury or even death.

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