New Study Evaluates the Use of Masimo PVi® As an Indicator of Fluid Responsiveness to Guide Goal-Directed Fluid Therapy in Adult Neurosurgical Patients

Masimo (NASDAQ: MASI) today announced the findings of a prospective study published in the British Journal of Neurosurgery in which Dr. Ankita Dey and colleagues at institutions in Bathinda and Pondicherry, India evaluated the use of noninvasive, continuous Masimo PVi^®, as part of goal-directed fluid therapy (GDFT), to guide intraoperative fluid administration during neurosurgery – the first study to evaluate PVi in this surgical scenario – by comparing it to a parameter obtained invasively, stroke volume variation (SVV). The researchers concluded that “PVi and SVV are equally effective for guiding intraoperative goal-directed fluid therapy in adult neurosurgical patients scheduled for elective craniotomy for supratentorial brain tumors. However, PVi, being a noninvasive parameter, may be preferable.”¹

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Noting the value of GDFT for neurosurgical patients in particular, but that most of the dynamic parameters traditionally used to guide GDFT, such as SVV, are invasive, requiring the use of an intra-arterial catheter (an arterial line, or “A-line”), which is associated with a variety of complications, the researchers sought to determine whether a noninvasive parameter, PVi, whose measurements are derived from the photoplethysmographic waveform, might serve as a reliable predictor of fluid responsiveness in such a population. PVi, or pleth variability index, is a measure of the variations in perfusion index over the respiratory cycle, and is indicated as a noninvasive, dynamic indicator of fluid responsiveness in select populations of mechanically ventilated adult patients.

To test their hypothesis, the researchers randomly divided 60 adult patients undergoing elective craniotomy into two groups: one whose intraoperative fluid administration was guided by PVi (n=29) and the other, by SVV (n=31). In the PVi group, patients were monitored using Masimo Radical-7^® Pulse CO-Oximeters^® with noninvasive pulse oximetry fingertip sensors. In the SVV group, SVV was invasively measured using an Edwards Lifesciences Vigileo/FloTrac device connected to a cannulated radial artery. The researchers compared the total amount of intravenous fluid administered during surgery, as well as serum lactate and serum creatinine levels at pre-determined time points, the brain relaxation score at dural opening and closure, and correlation between PVi and SVV values. They also compared duration of mechanical ventilation and length of hospital stay.

As noted in the table below, the researchers found that the volume of fluid administered intraoperatively was significantly higher in the SVV group. The other parameters and outcomes they measured were comparable between the two groups: serum lactate, serum creatinine, brain relaxation score, duration of mechanical ventilation, and length of hospital stay, as noted below. The researchers also observed “a moderate to strong correlation between SVV and PVi at corresponding points of time during the intraoperative period. This suggests that PVi, derived noninvasively from the pulse oximetry waveform, is a reliable indicator of fluid responsiveness.”

Outcome	PVi group	SVV group	p-Value
Volume of fluid administered	2139.3 ± 898.6 mL (mean)	3208.3 ± 1836.2 mL (mean)	0.005
Serum lactate level, over time	Ranging from 1.59 ± 0.91 to 2.73 ± 1.18	Ranging from 1.79 ± 0.97 to 2.44 ± 0.88	Ranging from 0.55 to 0.82
Serum creatinine level, over time	Ranging from 0.64 ± 0.14 to 0.66 ± 0.15 mg/dL	Ranging from 0.64 ± 0.17 to 0.71 ± 0.21 mg/dL	Ranging from 0.23 to 0.86
Brain relaxation score	2 (1-3) at dural opening, 2 (12) at dural closing (median)	2 (1-4) at dural opening and closing (median)	0.49 (opening) 0.33 (closing)
Duration of mechanical ventilation	19.09 ± 15.9 hours (mean)	27.9 ± 15.9 hours (mean)	0.1
Length of hospital stay	12.6 ± 19.26 days (mean)	16.4 ± 26.8 days (mean)	0.53

The researchers concluded, “Based on the findings of our study, we conclude that PVi and SVV are equally effective for guiding intraoperative goal directed fluid therapy in adult neurosurgical patients scheduled for elective craniotomy for supratentorial brain tumors. However, PVi, being a noninvasive parameter, may be preferable.” They continued, “The two groups in our study were comparable with respect to serum creatinine and serum lactate measured at predetermined time points intraoperatively and post operatively. The two groups were also comparable with respect to brain relaxation scores at dural opening and dural closure. There was moderate to strong correlation between SVV and PVi at corresponding time points intraoperatively. The duration of mechanical ventilation and the length of hospital stay was also comparable between the two groups.”

Joe Kiani, Founder and CEO of Masimo, said, “We introduced PVi in 2007. It was the first and still is the only noninvasive way of measuring fluid responsiveness in mechanically ventilated patients at a fraction of the cost of invasive methods and without risk of invasive procedures to the patient. Since then, over 100 studies have shown that PVi or PVi in combination with our noninvasive hemoglobin technology, SpHb^®, has made a tremendous contribution to patient care.² This latest study adds to the evidence that PVi can be used to help clinicians manage the fluid levels of their patients without invasive catheters.”

In the US, PVi is FDA 510(k) cleared as a noninvasive dynamic indicator of fluid responsiveness in select populations of mechanically ventilated adult patients. Accuracy of PVi in predicting fluid responsiveness is variable and influenced by numerous patient, procedure and device related factors. PVi measures the variation in the plethysmography amplitude but does not provide measurements of stroke volume or cardiac output. Fluid management decisions should be based on a complete assessment of the patient’s condition and should not be based solely on PVi.

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About Masimo

Masimo (NASDAQ: MASI) is a global medical technology company that develops and produces a wide array of industry-leading monitoring technologies, including innovative measurements, sensors, patient monitors, and automation and connectivity solutions. In addition, Masimo Consumer Audio is home to eight legendary audio brands, including Bowers & Wilkins, Denon, Marantz, and Polk Audio. Our mission is to improve life, improve patient outcomes, and reduce the cost of care. Masimo SET^® Measure-through Motion and Low Perfusion™ pulse oximetry, introduced in 1995, has been shown in over 100 independent and objective studies to outperform other pulse oximetry technologies.³ Masimo SET^® has also been shown to help clinicians reduce severe retinopathy of prematurity in neonates,⁴ improve CCHD screening in newborns,⁵ and, when used for continuous monitoring with Masimo Patient SafetyNet™ in post-surgical wards, reduce rapid response team activations, ICU transfers, and costs.^6-9 Masimo SET^® is estimated to be used on more than 200 million patients in leading hospitals and other healthcare settings around the world,¹⁰ and is the primary pulse oximetry at 9 of the top 10 hospitals as ranked in the 2022-23 U.S. News and World Report Best Hospitals Honor Roll.¹¹ In 2005, Masimo introduced rainbow^® Pulse CO-Oximetry technology, allowing noninvasive and continuous monitoring of blood constituents that previously could only be measured invasively, including total hemoglobin (SpHb^®), oxygen content (SpOC™), carboxyhemoglobin (SpCO^®), methemoglobin (SpMet^®), Pleth Variability Index (PVi^®), RPVi™ (rainbow^® PVi), and Oxygen Reserve Index (ORi™). In 2013, Masimo introduced the Root^® Patient Monitoring and Connectivity Platform, built from the ground up to be as flexible and expandable as possible to facilitate the addition of other Masimo and third-party monitoring technologies; key Masimo additions include Next Generation SedLine^® Brain Function Monitoring, O3^® Regional Oximetry, and ISA™ Capnography with NomoLine^® sampling lines. Masimo’s family of continuous and spot-check monitoring Pulse CO-Oximeters^® includes devices designed for use in a variety of clinical and non-clinical scenarios, including tetherless, wearable technology, such as Radius-7^®, Radius PPG^®, and Radius VSM™, portable devices like Rad-67^®, fingertip pulse oximeters like MightySat^® Rx, and devices available for use both in the hospital and at home, such as Rad-97^®. Masimo hospital and home automation and connectivity solutions are centered around the Masimo Hospital Automation™ platform, and include Iris^® Gateway, iSirona™, Patient SafetyNet, Replica^®, Halo ION^®, UniView^®, UniView :60™, and Masimo SafetyNet^®. Its growing portfolio of health and wellness solutions includes Radius Tº^® and the Masimo W1™ watch. Additional information about Masimo and its products may be found at www.masimo.com. Published clinical studies on Masimo products can be found at www.masimo.com/evidence/featured-studies/feature/.

ORi, RPVi, and Radius VSM have not received FDA 510(k) clearance and are not available for sale in the United States. The use of the trademark Patient SafetyNet is under license from University HealthSystem Consortium.

References

1. Dey A, Bidkar PU, Swaminathan S, Kumari M, Joy JJ, Balasubramanian M, Bhimsaria S. Comparison of two techniques of goal-directed fluid therapy in elective neurosurgical patients – a randomized controlled study. Br J Neuosurgery. 3 Feb 2023. DOI: 10.1080/02688697.2023.2173722/
2. Published clinical studies on PVi can be found on our website at http://www.masimo.com.
3. Published clinical studies on pulse oximetry and the benefits of Masimo SET^® can be found on our website at http://www.masimo.com. Comparative studies include independent and objective studies which are comprised of abstracts presented at scientific meetings and peer-reviewed journal articles.
4. Castillo A et al. Prevention of Retinopathy of Prematurity in Preterm Infants through Changes in Clinical Practice and SpO₂ Technology. Acta Paediatr. 2011 Feb;100(2):188-92.
5. de-Wahl Granelli A et al. Impact of pulse oximetry screening on the detection of duct dependent congenital heart disease: a Swedish prospective screening study in 39,821 newborns. BMJ. 2009;Jan 8;338.
6. Taenzer A et al. Impact of pulse oximetry surveillance on rescue events and intensive care unit transfers: a before-and-after concurrence study. Anesthesiology. 2010:112(2):282-287.
7. Taenzer A et al. Postoperative Monitoring – The Dartmouth Experience. Anesthesia Patient Safety Foundation Newsletter. Spring-Summer 2012.
8. McGrath S et al. Surveillance Monitoring Management for General Care Units: Strategy, Design, and Implementation. The Joint Commission Journal on Quality and Patient Safety. 2016 Jul;42(7):293-302.
9. McGrath S et al. Inpatient Respiratory Arrest Associated With Sedative and Analgesic Medications: Impact of Continuous Monitoring on Patient Mortality and Severe Morbidity. J Patient Saf. 2020 14 Mar. DOI: 10.1097/PTS.0000000000000696.
10. Estimate: Masimo data on file.
11. http://health.usnews.com/health-care/best-hospitals/articles/best-hospitals-honor-roll-and-overview.

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 include, among others, statements regarding the potential effectiveness of Masimo PVI^®, SpHb^®, and Radical-7^®. 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's unique noninvasive measurement technologies, including Masimo PVi, SpHb, and Radical-7, contribute to positive clinical outcomes and patient safety; risks that the researchers’ conclusions and findings may be inaccurate; risks related to our belief that Masimo noninvasive medical breakthroughs provide cost-effective solutions and unique advantages; risks related to COVID-19; 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 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.

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Contact information

Masimo
Evan Lamb
949-396-3376
elamb@masimo.com