New Study Affirms Masimo rainbow® Pulse CO-Oximetry(TM) Accuracy for Noninvasive Carboxyhemoglobin and Methemoglobin Measurements

July 9, 2012

IRVINE, Calif., July 9, 2012 /PRNewswire via COMTEX/ -- Masimo (NASDAQ: MASI) announced today a new study in Respiratory Physiology & Neurobiology shows that noninvasive carboxyhemoglobin (SpCO®) and methemoglobin (SpMet®) measurements with Masimo rainbow® Pulse CO-Oximetry(TM) are accurate and conclude they can be used as an effective first screening test with emergency room patients suspected of suffering carbon monoxide (CO) poisoning.(1)

CO poisoning is a major cause of morbidity and mortality(2) and is responsible for more than 50,000 emergency department visits per year in the United States.(3) Because symptoms of CO poisoning are nonspecific - ranging from mild headache, nausea, confusion, and dizziness to end-organ injury, such as myocardial infarction, stroke, and death - diagnosis is difficult and has historically relied on clinical suspicion and confirmation by measurement of carboxyhemoglobin (COHb) via invasive blood-gas analysis. Unfortunately, it has been estimated that up to half of U.S. hospitals do not have invasive COHb testing ability - increasing the potential that many victims of CO poisoning could be overlooked and misdiagnosed.(4)

The study was conducted on healthy subjects who inhaled a mixture that included carbon monoxide such that it raised the COHb to 10% to 14%. Investigators compared the mean bias and precision of SpCO and SpMet data obtained noninvasively with a Masimo Rad-57(TM) Pulse CO-Oximeter and adult reusable SpCO rainbow® sensor (DCI-dc3) with invasive venous blood samples analyzed on an arterial blood-gas analyzer (ABL80 FLEX CO-oximeter, Radiometer America).

The SpMet results showed the mean bias was 0.0% and precision was 0.3%. The SpCO measurements showed a mean bias of -0.8% and precision of 2.5%.

Researchers noted the Rad-57 "provides coherent and reproducible day-to-day measurement" of SpCO and SpMet, and concluded the "Rad-57 should be used as a first screening to determine whether an invasive blood measurement of COHb should be performed to confirm the (CO) intoxication."

(1) Zaouter C, Zavorsky G. "The measurement of carboxyhemoglobin and methemoglobin using a noninvasive pulse CO-oximeter." Respiratory Physiology & Neurobiology 2012 (

(2) Suner S, Patridge R, Sucov A, et al. "Noninvasive pulse CO-oximetry screening in the emergency department identifies occult carbon monoxide toxicity." J Emerg Med. 2008; 34(4):441-50.

(3) Weaver LK. "Carbon monoxide poisoning." N Engl J Med. 2009; 360(12):1217-1225.

(4) Hampson NB, Scott KL, Zmaeff JL. Carboxyhemoglobin measurement by hospitals: Implications for the diagnosis of carbon monoxide poisoning. J Emerg Med 2006;31(1):13-6.

About Masimo

Masimo (NASDAQ: MASI) is the global leader in innovative noninvasive monitoring technologies that significantly improve patient care--helping solve "unsolvable" problems. In 1995, the company debuted Measure-Through Motion and Low Perfusion pulse oximetry, known as Masimo SET®, which virtually eliminated false alarms and increased pulse oximetry's ability to detect life-threatening events. More than 100 independent and objective studies demonstrate Masimo SET provides the most reliable SpO2 and pulse rate measurements even under the most challenging clinical conditions, including patient motion and low peripheral perfusion. In 2005, Masimo introduced rainbow SET® Pulse CO-Oximetry(TM) technology, allowing noninvasive and continuous monitoring of blood constituents that previously required invasive procedures, including total hemoglobin (SpHb®), oxygen content (SpOC(TM)), carboxyhemoglobin (SpCO®), methemoglobin (SpMet®), and Pleth Variability Index (PVI®), in addition to SpO2, pulse rate, and perfusion index (PI). In 2008, the company introduced Masimo SafetyNet(TM), a remote monitoring and wireless clinician notification system designed to help hospitals avoid preventable deaths and injuries associated with failure to rescue events. In 2009, Masimo introduced rainbow Acoustic Monitoring(TM), the first-ever noninvasive and continuous monitoring of acoustic respiration rate (RRa(TM)). Masimo's rainbow SET technology platform offers a breakthrough in patient safety by helping clinicians detect life-threatening conditions and helping guide treatment options. In 2010, Masimo acquired SEDLine®, a pioneer in the development of innovative brain function monitoring technology and devices. Masimo SET and Masimo rainbow SET technologies can also be found in over 100 multiparameter patient monitors from over 50 medical device manufacturers around the world. Founded in 1989, Masimo has the mission of "Improving Patient Outcome and Reducing Cost of Care ... by Taking Noninvasive Monitoring to New Sites and Applications®." Additional information about Masimo and its products may be found at

Forward-Looking Statements

This press release includes forward-looking statements as defined in Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, in connection with the Private Securities Litigation Reform Act of 1995. These forward-looking statements are based on current expectations about future events affecting us and are subject to risks and uncertainties, all of which are difficult to predict and many of which are beyond our control and could cause our actual results to differ materially and adversely from those expressed in our forward-looking statements as a result of various risk factors, including, but not limited to: risks related to our assumptions of the repeatability of clinical results obtained using the new Masimo Pronto-7 and noninvasive sensor sizes, risks related to our belief that the Pronto-7 enables quick and easy noninvasive spot-checking of hemoglobin (SpHb®), SpO2, pulse rate, and perfusion index at the point-of-care for all patients, as well as other factors discussed in the "Risk Factors" section of our most recent reports filed with the Securities and Exchange Commission ("SEC"), which may be obtained for free at the SEC's website at Although we believe that the expectations reflected in our forward-looking statements are reasonable, we do not know whether our expectations will prove correct. All forward-looking statements included in this press release are expressly qualified in their entirety by the foregoing cautionary statements. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of today's date. We do not undertake any obligation to update, amend or clarify these statements or the "Risk Factors" contained in our most recent reports filed with the SEC, whether as a result of new information, future events or otherwise, except as may be required under the applicable securities laws.

Media Contact:
Mike Drummond
Masimo Corporation
Phone: (949) 297-7434

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