New Study Demonstrates Masimo's Noninvasive PVI(TM) Measurement Can Predict Fluid Responsiveness During Surgery

July 10, 2008

Publication in 'British Journal of Anaesthesia' reveals PVI has similar or better accuracy compared to multiple invasive methods

IRVINE, Calif., July 10 /PRNewswire-FirstCall/ -- Masimo (Nasdaq: MASI), the inventor of Pulse CO-Oximetry and Measure-Through-Motion-and-Low-Perfusion pulse oximetry, today announced that a new clinical study, published in the June 2008 issue of the British Journal of Anaesthesia, concluded that under the study protocol Masimo's PVI measurement "can predict fluid responsiveness in mechanically-ventilated patients under general anesthesia." PVI is a new measurement available in the Masimo Rainbow SET technology platform that allows noninvasive, automated, and continuous monitoring of the variation in the pulse oximeter waveform amplitude during respiration.

During surgery, one of the biggest challenges anesthesiologists face is deciding whether to administer fluid to increase cardiac index (amount of blood the heart pumps each minute) and maintain an adequate delivery of oxygen to the body. However, multiple studies have shown that traditional invasive measurements are only 50 to 60% accurate at predicting an improvement in cardiac index after volume administration.(1) Administration of unnecessary fluid should be avoided because it is associated with increased morbidity and mortality.(2) Newer invasive measurements that are based on dynamic changes during the respiratory cycle have shown improved accuracy at predicting fluid responsiveness, but market adoption has been slow due to complexity and cost. Therefore, a noninvasive method to accurately assess fluid responsiveness and guide fluid administration would provide tremendous value to clinicians and patients alike.

In the British Journal of Anaesthesia study, a patient was defined as a "responder" if their cardiac index increased by 15% or more after administration of 500 ml of fluid. If cardiac index increased less than 15% after volume administration, the patient was defined as a "non-responder". Of the 25 patients evaluated in the study, 16 were considered responders and 9 were considered non-responders. PVI showed a similar accuracy (0.93 area under the curve, AUC) at predicting fluid responsiveness when compared to pulse pressure variation from an invasive arterial catheter (0.94 AUC) and superior accuracy when compared to central venous (0.42 AUC) or pulmonary capillary wedge pressure (0.40) (Click Below Link for Chart).(3)


"PVI demonstrated high accuracy in discriminating fluid responders from non-responders-providing a unique opportunity to better manage a patient's fluid volume to optimize cardiac performance and organ perfusion," stated Maxime Cannesson, M.D., lead researcher and anesthesiologist, Louis Pradel Hospital in Lyon, France. "14 of the 16 patients who responded to fluid administration with a cardiac index increase of 15% or more had a PVI value of >14% before volume administration. All 9 patients who did not respond to fluid administration with a cardiac index increase of 15% or more had a PVI value of <14% before volume administration."

According to a recent clinical study published in Critical Care, monitoring pulse pressure variation with an arterial catheter showed an ability "to decrease the duration of hospital stay, mechanical ventilation, and post-operative morbidity in patients undergoing high-risk surgery".(4) While pulse pressure variation from an arterial pressure catheter is considered the gold standard for assessing fluid responsiveness, only a small minority of patients receive this type of catheter during surgery due to its invasiveness, complexity, and risk. In Dr. Cannesson's study, Masimo PVI showed similar accuracy as pulse pressure variation at predicting fluid responsiveness but offers clinicians an easy and noninvasive assessment of fluid responsiveness in any patient undergoing surgery by simply using their existing noninvasive Masimo SpO2 sensor with Masimo Rainbow SET monitors.

Joe E. Kiani, Chairman and CEO of Masimo, stated, "The excellent work of Dr. Cannesson and colleagues adds to the growing body of evidence supporting the use of PVI as a new standard of care to optimize fluid status in patients both in the operating room and at the bedside. We are happy to see that yet another one of our inventions has the potential to improve outcomes and increase safety for patients."

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, 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, a breakthrough noninvasive blood constituent monitoring platform that can measure many blood constituents that previously required invasive procedures. Masimo Rainbow SET continuously and noninvasively measures total hemoglobin (SpHb(TM)), oxygen content (SpOC(TM)), carboxyhemoglobin (SpCO(R)), methemoglobin (SpMet(R)), and PVI(TM), in addition to oxyhemoglobin (SpO2), pulse rate (PR), and perfusion index (PI), 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

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 the positive results and clinical outcomes presented on PVI will be repeated in other studies, risks related to our assumption that PVI will deliver a sufficient level of clinical improvement over alternative methods of monitoring respiratory variations in the pulse oximetry plethysmographic waveform amplitude to allow for rapid adoption of the technology, as well as other factors discussed in the "Risk Factors" section of our quarterly report on Form 10-Q for the quarter ended March 29, 2008, filed with the Securities and Exchange Commission on May 1, 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 quarterly report on Form 10-Q for the quarter ended March 29, 2008, whether as a result of new information, future events or otherwise, except as may be required under the federal securities laws.

Dana Banks
Masimo Corporation

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, Radical-7, Rad-87, Rad-57, Rad-9, Rad-8, Rad-5, Pulse CO-Oximetry and Pulse CO-Oximeter are trademarks or registered trademarks of Masimo Corporation.

(1) Michard F, Teboul JL. Predicting fluid responsiveness in ICU patients: a critical analysis of the evidence. Chest. 2002 Jun;121(6):2000-8.

(2) Joshi G. "Intraoperative Fluid Restriction Improves Outcome After Major Elective Gastrointestinal Surgery." Anesthesia Analgesia (2005) 101:601-5.

(3) Cannesson M, Desebbe O, Rosamel P, Delannoy B, Robin J, Bastien O, Lehot JJ. "Pleth variability Index to Monitor the Respiratory Variations in the Pulse Oximeter Plethysmographic Waveform Amplitude and Predict Fluid Responsiveness in the Operating Theatre." British Journal of Anaesthesia 2008; 0:aen133v1-7.

(4) Lopes MR, Oliveira MA, Pereira VO, Lemos IP, Auler JO Jr, Michard F. "Goal-directed Fluid Management Based on Pulse Pressure Variation Monitoring During High-risk Surgery: A Pilot Randomized Controlled Trial." Critical Care 2007; 11: R100.

SOURCE Masimo Corporation