New Multi-Center Study Demonstrates Masimo PVI Predicts the Hemodynamic Effects of Positive End-Expiratory Pressure (PEEP)

March 31, 2010
Researchers Conclude that PVI May be Useful in Automatically and Noninvasively Detecting the Deleterious Effects of PEEP in Ventilated and Sedated Patients

IRVINE, Calif., March 31, 2010 /PRNewswire via COMTEX/ --Masimo (Nasdaq: MASI), the inventor of Pulse CO-Oximetry(TM) and Measure-Through Motion and Low Perfusion pulse oximetry, announced today that a new clinical study published in the March 2010 issue of Anesthesia & Analgesia, shows Masimo PVI successfully predicts the hemodynamic effects of Positive End-Expiratory Pressure (PEEP) in mechanically ventilated patients after cardiac surgery. According to study researchers, the ability of PVI to predict the effects of PEEP may allow physicians to "optimize the respiratory uptake in oxygen and its delivery to the tissues." (1)

It is critically important for clinicians to accurately determine whether the addition of PEEP, a ventilator setting that can alter cardiac output (the amount of blood the heart pumps), will have positive or negative hemodynamic effects. PEEP can be beneficial if it improves PaO2 (arterial oxygenation and oxygen delivery during anesthesia) by opening collapsed alveoli to increase gas exchange, but harmful if it decreases blood flow to the tissues (most often measured as cardiac output). Masimo PVI has been shown on multiple clinical studies to continuously and noninvasively predict fluid responsiveness in mechanically-ventilated patients under general anesthesia. However, researchers in this study approached the relationship between PVI and fluid responsiveness in the reverse manner from which it is usually evaluated. Instead of looking at whether PVI predicts a positive response by the patient, they evaluated whether PVI predicated a negative response (decreased preload) with the addition of PEEP.

Researchers from the Louis Pradel Hospital, Department of Anesthesiology and Intensive Care, in Lyon, France, and the University of California, Irvine, School of Medicine in Irvine, California, studied 21 mechanically-ventilated and sedated patients in the postoperative period after coronary artery bypass graft (CABG) surgery. Patients were monitored via invasive pulmonary artery catheter for end-expiratory central venous pressure (CVP), end-expiratory pulmonary capillary wedge pressure (PCWP), cardiac index (cardiac output indexed to body surface area) (CI), pulse pressure variation, and stroke volume (SV), and PVI via a Masimo Rainbow SET Pulse CO-Oximeter sensor attached to the finger. Hemodynamic data was recorded at three successive tidal volumes (VT of 6, 8, and 10 mL/kg) during zero end-expiratory pressure (ZEEP) and after the addition of 10 cm H2O PEEP for each VT and hemodynamically instable (HI) patients were defined as those with >15% decrease in CI after the addition of PEEP.

Results showed that at a VT of 8 mL/kg, PVI was significantly higher in the HI group than in the non-HI group (13% + 5% vs 9% + 4%, P<0.03) and a PVI of 12% at ZEEP predicted a significant decrease in CI after the addition of PEEP in 6 patients with a sensitivity of 83% and a specificity of 80%. Pulse pressure variation was also significantly higher in the HI group than in the non-HI group; however CI, CVP, and PCWP were not different. At VT of 10 mL/kg, PVI was still significantly higher in the HI group than in the non-HI group (16% + 7% vs 10% + 4%, P<0.01) and a PVI of 13% at ZEEP predicted a significant decrease in CI after the addition of PEEP in 9 patients with a sensitivity of 78% and a specificity of 83%. Researchers concluded that Masimo PVI may be "useful in automatically and noninvasively detecting the hemodynamic effects of PEEP when VT is > 8 mL/kg in ventilated and sedated patients with acceptable sensitivity and specificity."

The current study reinforces the value of PVI compared to invasive measures and highlights PVI's value for reliably detecting the hemodynamic effects of PEEP and predicting hemodynamic instability. PVI is available as part of Masimo Rainbow SET Pulse CO-Oximetry--a breakthrough noninvasive blood constituent monitoring platform capable of measuring multiple blood constituents that previously required invasive procedures, including: total hemoglobin (SpHb(R)), oxygen content (SpOC(TM)), carboxyhemoglobin (SpCO(R)), methemoglobin (SpMet(R)), and PVI(R), in addition to oxyhemoglobin (SpO2), pulse rate (PR), and perfusion index (PI).

1. Desebbe, Olivier, Boucau, Ce'cile, Farhat, Fadi, Bastien, Olivier, Lehot, Jean-Jacques, and Cannesson, Maxime. "The Ability of Pleth Variability Index to Predict the Hemodynamic Effects of Positive End-Expiratory Pressure in Mechanically-Ventilated Patients Under General Anesthesia." Anesthesia & Analgesia. March 2010, vol. 110, no. 3, pages 792-798. Available online at: www.anesthesia-analgesia.org/content/110/3/792.full.pdf+html

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(R), 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 Masimo Rainbow SET(R) Pulse CO-Oximetry(TM), allowing noninvasive and continuous monitoring of blood constituents that previously required invasive procedures, including total hemoglobin (SpHb(R)), oxygen content (SpOCTM), carboxyhemoglobin (SpCO(R)), methemoglobin (SpMet(R)), and PVI(R), in addition to SpO2, pulse rate, and perfusion index (PI). In 2009, Masimo introduced Masimo Rainbow SET(R) Acoustic Monitoring(TM), the first-ever noninvasive and continuous monitoring of acoustic respiration rate (RRa(TM)). Masimo's Rainbow platform offers a breakthrough in patient safety by helping clinicians detect life-threatening conditions and helping guide treatment options. 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 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 regarding the repeatability of clinical results, risks related to our belief that Masimo PVI will be useful in automatically and noninvasively detecting the deleterious effects of PEEP in all ventilated and sedated patients, and risks related to our belief that Masimo Rainbow SET Pulse CO-Oximetry noninvasive measurements (specifically SpHb, PVI, and SpO2) will provide sufficient sensitivity and specificity to help clinicians proactively monitor and manage hemoglobin, fluid and oxygen saturation levels more appropriately and conservatively 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 www.sec.gov. 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 forward-looking 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 Contacts:
Dana Banks
Masimo Corporation
(949) 297-7348
dbanks@masimo.com

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