New Study Uses Masimo SedLine® Brain Function Monitoring to Assess the Prevalence of Isoelectric EEG Events in Infants and Young Children Undergoing General Anesthesia

June 24, 2019

IRVINE, Calif.--(BUSINESS WIRE)--Jun. 24, 2019-- Masimo (NASDAQ: MASI) announced today that in a study recently published in Anesthesia & Analgesia, researchers investigated the incidence of isoelectric electroencephalogram (EEG) events in infants and young children undergoing scheduled surgery requiring general anesthesia.1 To assess the prevalence of these events, the researchers used Masimo SedLine® brain function monitoring, available on the Root® Patient Monitoring and Connectivity Platform, which uses four leads and bilateral data acquisition to process frontal EEG signals. Because a subset of patients was also monitored with 10-channel EEG, the researchers were able to evaluate SedLine’s accuracy and utility in such a scenario.

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Masimo Root® with SedLine® (Photo: Business Wire)

Masimo Root® with SedLine® (Photo: Business Wire)

Dr. Ian Yuan and colleagues at the Children’s Hospital of Philadelphia, the University of Pennsylvania, and Drexel University sought to evaluate the incidence of isoelectric EEG events in pediatric patients because anesthetic doses may be “greater than needed for surgery” in some infants and young children and isoelectric EEG events are associated with deep anesthesia (and in adults undergoing cardiac surgery, with “a higher incidence of postoperative delirium”). They evaluated 51 patients from 0 to 37 months old scheduled for surgery requiring general anesthesia (excluding cardiac, intracranial, and emergency cases). Anesthesia was maintained with sevoflurane or propofol infusion.

Noting that “Conventional 10- to 24-channel EEG is impractical for pediatric anesthesia as it is labor intensive and requires special training in both performance and interpretation,” the researchers chose to record EEG for the duration of anesthesia using Masimo SedLine. To evaluate whether isoelectric events were generalized beyond the frontal cortex, they also recorded simultaneous data using 10-electrode EEG (Natus Xltek) for 10 patients (2-10 months old). Isoelectric events were defined as EEG with amplitude <20 μV for ≥2 seconds.

The researchers found that isoelectric events occurred in 63% of patients (95% confidence interval of 49% - 76%), representing 0% - 2.2% of total anesthetic time. A pediatric electroencephalographer compared the EEG recordings for 9 of the 10 patients monitored with both SedLine and 10-channel EEG and found that isoelectric events observed with SedLine were also observed across all channels with 10-channel EEG, noting “The Matlab program identified 47 isoelectric events from the SedLine EEG, and all events were confirmed by the electroencephalographer.”

Dr. Yuan commented, “We were surprised by how prevalent isoelectric EEG occurred in healthy infants and young children undergoing routine general anesthesia, regardless of anesthetic technique. The Masimo SedLine EEG could be applied quickly without interfering with anesthesia care and could accurately record EEG in infants and young children in the operating room, suggesting it could be used to adjust anesthesia dosing.”

Study co-author Dr. C. Dean Kurth added, “Pediatric anesthesiologists often unknowingly administer more sevoflurane or propofol anesthesia to infants and young children than their brain requires to produce anesthesia.”

Regarding the use of SedLine, the researchers concluded, “Although the SedLine EEG monitors only frontal cortex, the 10-electrode EEG showed that the isoelectric events were generalized to the parietal, temporal, and occipital cortices as well, suggesting that the SedLine EEG could be used to monitor anesthetic-related isoelectric events.” They continued, “EEG monitoring may enable dose titration to optimize the anesthetic depth and minimize periods of isoelectricity. Our results suggest that portable 4-channel EEG monitors are feasible for this purpose.” With SedLine, periods of isoelectricity, or burst suppression, are easily visible on the Density Spectral Array (DSA), a color-coded display of processed EEG power, as black bars.

SedLine and Next Generation SedLine have received FDA clearance for use on adult patients. Next Generation SedLine has received CE marking for use on pediatric patients (one year old and above).

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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. Our mission is to 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.2 Masimo SET® has also been shown to help clinicians reduce severe retinopathy of prematurity in neonates,3 improve CCHD screening in newborns,4 and, when used for continuous monitoring with Masimo Patient SafetyNet™ in post-surgical wards, reduce rapid response team activations, ICU transfers, and costs.5-7 Masimo SET® is estimated to be used on more than 100 million patients in leading hospitals and other healthcare settings around the world,8 and is the primary pulse oximetry at 9 of the top 10 hospitals listed in the 2018-19 U.S. News and World Report Best Hospitals Honor Roll.9Masimo continues to refine SET® and in 2018, announced that SpO2 accuracy on RD SET™ sensors during conditions of motion has been significantly improved, providing clinicians with even greater confidence that the SpO2 values they rely on accurately reflect a patient’s physiological status. 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® and Radius™ PPG, 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 automation and connectivity solutions are centered around the Iris® platform, and include Iris Gateway™, Patient SafetyNet, Replica™, Halo ION™, UniView™, and Doctella™. Additional information about Masimo and its products may be found at Published clinical studies on Masimo products can be found at

ORi and RPVi 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.


  1. Yuan I, Landis W, Topjian A, Abend N, Lang S, Huh J, Kirschen M, Mensinger J, Zhang B, and Kurth C. Prevalence of Isoelectric Electroencephalography Events in Infants and Young Children Undergoing General Anesthesia. Anesth Analg. 2019. DOI: 10.1213/ANE.0000000000004221
  2. Published clinical studies on pulse oximetry and the benefits of Masimo SET® can be found on our website at Comparative studies include independent and objective studies which are comprised of abstracts presented at scientific meetings and peer-reviewed journal articles.
  3. 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.
  4. 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.
  5. 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.
  6. Taenzer A et al. Postoperative Monitoring – The Dartmouth Experience. Anesthesia Patient Safety Foundation Newsletter. Spring-Summer 2012.
  7. 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.
  8. 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; risks related to our belief that Masimo noninvasive medical breakthroughs provide cost-effective solutions and unique advantages; 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.

Source: Masimo

Evan Lamb