New Study Compares Performance of Masimo Next Generation SedLine® Patient State Index (PSi) to Original PSi During Anesthesia

(NASDAQ: MASI) announced today the findings of an abstract presented at Euroanaesthesia
in Geneva, Switzerland. In the study, researchers at University
Medical Center Groningen, Netherlands, compared original and Next
Generation versions of Masimo Patient State Index (PSi, a processed EEG
parameter related to the effect of anesthetic agents) during Masimo
SedLine® brain function monitoring of patients under propofol
and sevoflurane anesthesia.1

SedLine brain function monitoring features four simultaneous EEG leads
to enable continuous assessment of both sides of the brain, four EEG
waveforms, a Density Spectral Array (DSA, an easy-to-interpret,
high-resolution display of bi-hemispheric activity and EEG power), and
PSi. Next Generation SedLine enhances PSi to make it less susceptible to
electromyographic (EMG) interference and to improve its performance in
low-power EEG cases.

In the study, Dr. Kuizenga and colleagues sought to compare the original
and Next Generation PSi algorithms, referred to as PSi-1 and PSi-2,
respectively, as they correlated with propofol and sevoflurane drug
concentrations and with the Modified Observers Assessment of Alertness
and Sedation (MOAAS) scale. They also sought to assess the influence of
2 and 4 ng/mL effect-site concentrations of remifentanil on the
performance of the two algorithms.

The researchers enrolled 36 healthy volunteers, stratified by age, and
assigned them randomly to a sequence of four sessions of anesthesia. In
one session, propofol was administered in a series of graded steps; in
the second, sevoflurane was similarly administered; in the third and
fourth, the two concentrations of remifentanil were also administered.
During each step of each session, after a twelve-minute delay for
equilibration, MOAAS was tested and a blood sample was taken to measure
drug concentrations. EEG was collected using Masimo Root®
with SedLine®, from which time-synchronized PSi-1 and PSi-2
values were later extracted. The researchers then plotted MOAAS, drug
concentration, PSi-1, and PSi-2 values over time.

The researchers found that when charted against drug concentrations,
PSi-2 showed “reduced population variability and improved baseline
stability” compared to PSi-1. When charted against MOAAS, PSi-2 had
“lower interindividual variability” than PSi-1. They also noted that
“Both PSis distinguish MOAAS 5, 4, and 3 better during propofol
anesthesia compared to sevoflurane. This difference disappears when
adding remifentanil.”

The investigators concluded that “PSi-2 [Next Generation SedLine PSi]
has enhanced signal stability and a better description of the
dose-response relationship. PSi-2 has therefore improved capacity as a
pharmacodynamic monitor of anesthesia compared to PSi-1.”

Next Generation SedLine has not received FDA 510(k) clearance and is not
available for sale in the United States.

@MasimoInnovates |


  1. Kuizenga M.H., Colin P.J., Vereecke H.E.M., Struys M.M.R.F. Comparison
    between two versions of the Patient State Index during propofol and
    sevoflurane anesthesia, with or without remifentanil. Proceedings from
    Euroanaesthesia 2017, Geneva, Switzerland. Abstract #01AP07-4.

About Masimo

Masimo (NASDAQ: MASI) is a global leader in innovative noninvasive
monitoring technologies. Our mission is to improve patient outcomes and
reduce the cost of care. In 1995, the company debuted Masimo SET®
Measure-through Motion and Low Perfusion™ pulse oximetry, which has been
shown in multiple studies to significantly reduce false alarms and
accurately monitor for true alarms. Masimo SET® has also been
shown to help clinicians reduce severe retinopathy of prematurity in
neonates,1 improve CCHD screening in newborns,2
and, when used for continuous monitoring with Masimo Patient SafetyNet™*
in post-surgical wards, reduce rapid response activations and costs.3,4,5
Masimo SET® is estimated to be used on more than 100 million
patients in leading hospitals and other healthcare settings around the
world,6 and is the primary pulse oximetry at 16 of the top 20
hospitals listed in the 2016-17 U.S. News and World Report Best
Hospitals Honor Roll.7 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®), and more recently, Pleth Variability Index (PVi®)
and Oxygen Reserve Index (ORi™), in addition to SpO2, pulse
rate, and perfusion index (PI). In 2014, Masimo introduced Root®,
an intuitive patient monitoring and connectivity platform with the
Masimo Open Connect™ (MOC-9™) interface, enabling other companies to
augment Root with new features and measurement capabilities. Masimo is
also taking an active leadership role in mHealth with products such as
the Radius-7™ wearable patient monitor, iSpO2®
pulse oximeter for smartphones, and the MightySat™ fingertip pulse
oximeter. Additional information about Masimo and its products may be
found at
Published clinical studies on Masimo products can be found at

*The use of the trademark Patient SafetyNet is under license from
University HealthSystem Consortium.


  1. 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.
  2. 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;338.
  3. Taenzer AH 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.
  4. Taenzer AH et al. Postoperative Monitoring – The Dartmouth Experience. Anesthesia
    Patient Safety Foundation Newsletter
    . Spring-Summer 2012.
  5. McGrath SP 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.
  6. Estimate: Masimo data on file.

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 SedLine®.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 SedLine, contribute to
positive clinical outcomes and patient safety; 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.


Evan Lamb, 949-396-3376