New Clinical Studies Presented at the 14th World Congress of Anesthesiology Demonstrate Masimo Advancements in Patient Care

March 6, 2008

Noninvasive Hemoglobin Receives Rave Reviews from Attendees at Masimo's Commercial Exhibit

IRVINE, Calif., March 6 /PRNewswire-FirstCall/ -- Masimo, the inventor of Pulse CO-Oximetry(TM) and Measure-Through Motion and Low Perfusion pulse oximetry, reported that multiple clinical studies demonstrating the accuracy and clinical effectiveness of the Masimo Rainbow SET platform were highlighted earlier this week to over 8,000 anesthesiologists at the 14th World Congress of Anesthesiology (WCA) in Cape Town, South Africa. In addition, WCA attendees from all over the world were able to preview noninvasive total hemoglobin (SpHb(TM)) and oxygen content (SpOC(TM)) as part of the Rainbow SET platform (pending FDA clearance).

                          Clinical Study Highlights

Continuous Noninvasive Measurement of Hemoglobin via Pulse CO-Oximetry(1), a clinical study led by Dr. Mark Macknet at Loma Linda University in Loma Linda, California, presented a study that compared an engineering prototype of Masimo Rainbow SET noninvasive total hemoglobin (SpHb) to invasive laboratory hemoglobin measurements in two groups. Group one included 55 patients scheduled to undergo surgery, while group two consisted of 32 healthy volunteers undergoing a hemodilution protocol. After reviewing 1,538 data pairs, researchers found that the Masimo technology accurately delivered total hemoglobin levels, with the study showing accuracy of 1.28 mg/dl and 0.94 mg/dl for group two, respectively, when compared to invasive laboratory CO-Oximetry. Researchers concluded that Masimo's device is the "first device developed that can continuously and noninvasively measure hemoglobin concentration, in addition to the other common hemoglobin species, and therefore provides a significant expansion of existing physiologic monitoring technology."

Casual Screening of Hemoglobin Noninvasively Positively Affects a Colleague's Future(2), a case report by Dr. Martin Allard at Loma Linda University recounted the application of SpHb to assess an anemic hemoglobin level of 10.6 g/dl on a fellow anesthesiologist who otherwise appeared healthy. Invasive hemoglobin testing confirmed the measurement and further diagnostic testing revealed previously undiagnosed and asymptomatic esophageal cancer. Researchers concluded that Masimo SpHb allowed the "detection of this potentially devastating tumor before clinical signs or symptoms became apparent, which resulted in early intervention and therapy that may well be curative for this colleague."

New Pulse Oximetry Sensors with Low Saturation Accuracy Claims(3), performed by Dr. Peter Cox at the Hospital for Sick Children in Toronto, Canada, evaluated 12 patients with congenital cyanotic cardiac lesions (CCCL) to compare noninvasive oxyhemoglobin (SpO2) measurements from the Masimo Rainbow SET Radical 7 device with Blue Sensor and the Covidien N-600 device (OxiMax with Lo-Sat) to invasive oxyhemoglobin levels from laboratory CO-Oximetry. Although the Nellcor N-600 with LoSat is advertised to work in CCCL patients, the accuracy demonstrated in this study was 6.49%, well outside of Nellcor's published specifications. In contrast, the Masimo Radical with Blue Sensor, the first and only sensor with accuracy claims cleared for cyanotic patients, performed within Masimo specifications and had significantly better accuracy at 3.85%. Study results demonstrate that the Masimo Blue sensor, which was "designed for use specifically in this patient population, is more accurate." Dr. Peter Cox, Hospital for Sick Children in Toronto, Canada, said, "Accurate monitoring of oxygen saturations in children with cyanotic congenital heart defects is essential for appropriate patient management and, therefore, its impact on their long-term outcome. The Masimo Blue Sensor accurately tracks saturation to levels as low as 60%, which will greatly assist caregivers in the management of this patient population."

Severe Methemoglobinemia Detected by Pulse CO-Oximetry in the Operating Room(4), a case report by Dr. Steven J. Barker and Dr. E. H. Annabi at the University of Arizona in Tucson, Arizona, documented the use of Masimo noninvasive methemoglobin (SpMet(R)) to accurately diagnose a severe case of drug-induced methemoglobinemia and subsequently monitor and guide the patient's treatment and recovery. Researchers concluded that Masimo SpMet can "quickly diagnose" methemoglobinemia in the perioperative setting, where time is of the utmost essence.

                        Commercial Exhibit Highlights

Masimo also previewed, for the first time, continuous noninvasive total hemoglobin (SpHb) and oxygen content (SpOC) as part of the Rainbow SET platform during WCA's commercial exhibition. In the first five hours alone, an astounding number of over 1,000 anesthesiologists visited the booth and experienced first-hand product demonstrations and clinical presentations of the new SpHb and SpOC parameters, along with Masimo's measure-through motion and low perfusion pulse oximeters. Scores of anesthesiologists who perform invasive hemoglobin testing routinely during surgery were amazed by the ability to get their own hemoglobin levels tested noninvasively in just seconds. In fact, anesthesiologists were heard proclaiming "this changes everything" and "noninvasive hemoglobin will revolutionize anesthesiology!"

"The new clinical evidence for Masimo Rainbow SET and preview of SpHb and SpOC were extremely well-received by anesthesiologists from around the world at the WCA," stated Joe E. Kiani, Founder and CEO of Masimo. "We are proud to once again revolutionize noninvasive monitoring for the benefit of patient care."

Michael O'Reilly, MD, EVP of Medical Affairs at Masimo, stated, "Noninvasive total hemoglobin represents an exciting and valuable expansion of the noninvasive hemodynamic capabilities available to anesthesiologists. Many of whom remarked that the ability to see total hemoglobin and oxygen content measurements, along with carboxyhemoglobin (SpCO(R)), methemoglobin (SpMet), pleth variability index (PVI(TM)), perfusion index (PI), oxygen saturation (SpO2) and pulse rate -- all on one screen, with one device and one sensor, was equally impressive."

About Masimo

Masimo (Nasdaq: MASI) develops innovative 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, and with it 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 trustworthy SpO2 and pulse rate measurements even under the most difficult clinical conditions, including patient motion and low peripheral perfusion. In 2005, Masimo introduced Masimo Rainbow SET, a breakthrough noninvasive blood constituent monitoring platform that can measure many blood constituents that previously required invasive procedures. Rainbow SET continuously and noninvasively measures total hemoglobin (SpHb(TM)), oxygen content (SpOC(TM)), carboxyhemoglobin (SpCO(R)), methemoglobin (SpMet(R)), and pleth variability index (PVI(TM)), in addition to oxyhemoglobin (SpO2), perfusion index (PI) and pulse rate, allowing early detection and treatment of potentially life-threatening conditions. Founded in 1989, Masimo has the mission of "Improving Patient Outcomes 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 http://www.masimo.com.

Forward Looking Statements

This press release may include forward-looking statements. These forward-looking statements are based on current expectations about future events affecting us and are subject to uncertainties and factors, all of which are difficult to predict and many of which are beyond our control, including: risks related to our assumption that Masimo's new noninvasive measurements -- total hemoglobin (SpHb(TM)) and oxygen content (SpOC(TM)) -- will deliver a sufficient level of clinical improvement over alternative hemoglobin testing capabilities to allow for rapid adoption of the technology and risks related to our assumptions regarding the timing or commercial availability of SpHb and SpOC, and will be timely cleared, if ever, by appropriate regulatory bodies, as well as other factors discussed in the "Risk Factors" section of our annual report on Form 10-K for the year ended December 29, 2007, filed with the Securities and Exchange Commission on March 4, 2008. Although we believe that the expectations reflected in our forward-looking statements are reasonable, we do not know whether our expectations will prove correct. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. We do not undertake any obligation to update, amend or clarify these forward-looking statements or the risk factors contained in our annual report on Form 10-K for the year ended December 29, 2007, whether as a result of new information, future events or otherwise, except as may be required under the federal securities laws.

    (1) Continuous Noninvasive Measurement of Hemoglobin via Pulse
        CO-Oximetry. Mark R. Macknet, Penny L. Kimball-Jones, Richard L.
        Applegate, Robert D. Martin, Martin W. Allard. Anesthesiology, Loma
        Linda University, Loma Linda, CA.
    (2) Casual Screening of Hemoglobin Noninvasively Positively Affects a
        Colleague's Future. Martin Allard, John Viljoen, Mark Macknet.
        Anesthesiology, Loma Linda University, Loma Linda, CA.
    (3) New Pulse Oximetry Sensors with Low Saturation Accuracy Claims. Peter
        Cox. Department of Critical Care Medicine, Hospital for Sick Children,
        Toronto, Canada.
    (4) Severe Methemoglobinemia Detected by Pulse CO-Oximetry in the
        Operating Room. S. J. Barker, E.H. Annabi.  Anesthesiology, University
        of Arizona, Tucson, AZ.

Masimo, SET, Signal Extraction Technology, Improving Outcomes and Reducing Cost of Care by Taking Noninvasive Monitoring to New Sites and Applications, Rainbow, SpHb, SpOC, SpCO, SpMet, PVI, and Pulse CO-Oximeters are trademarks or registered trademarks of Masimo Corporation.

SOURCE Masimo Corporation

CONTACT: Dana Banks of Masimo Corporation, +1-949-297-7348

Web site: http://www.masimo.com