A while back, Masimo acquired a Canadian firm that developed a novel bioacoustic respiratory sensor. The fruits of that acquisition are soon to be on the market (press release). In recent studies, "Masimo Acoustic Respiratory Monitoring technology (ARM) is "at
least as accurate as capnometry" and "significantly more reliable" for
monitoring respiration in spontaneously breathing patients."

Respiration is one of the five vital signs, but clinicians have long
looked for a continuous and noninvasive method of monitoring
respiration that is both clinically accurate, easy to use, and well
tolerated by patients. Current methods of respiration monitoring,
including impedance pneumography with ECG and end-tidal CO2 with capnometry, each have limitations that make them unreliable in certain clinical situations.

At the Rapid Response Systems conference last month in Pittsburgh, studies were presented indicating that the most important parameter for identifying patients with deteriorating clinical conditions is respiration. At the same time, those studies showed that respiration was the most poorly documented physiological parameter - by far. A common problem with respiration is manually assessing the respiration rate through observation, that's why many recordings show a standard 12 breaths per minute.

Masimo also indicates in this same press release that we can see a product built around this parameter:

Masimo expects to combine its Masimo Rainbow SET Read-Through Motion
and Low Perfusion pulse oximetry with Masimo ARM technology as part of
a general floor monitoring solution designed to increase patient safety
and heed the growing call to find ways reduce unnecessary deaths on
general care floors. The combination of these two technologies will
give hospitals a continuous and noninvasive way to accurately monitor a
patient's oxygenation and ventilation during patient-controlled
analgesia, consistent with the new recommendations from the Anesthesia
Patient Safety Foundation (APSF). In addition, the combination of
Masimo Rainbow SET pulse oximetry and Masimo ARM should assist
hospitals in being compliant with new American Society of Anesthesia
(ASA) guidelines for management of patients at risk of obstructive
sleep apnea (OSA) by providing an accurate and reliable combination of
oxygen saturation and respiration rate monitoring.

Pictured right is the respiratory bioacoustic sensor. You can read a story in Anesthesia News, and one of the papers (pdf).