Researchers Harness the Power of Masimo Root®’s Advanced Multimodal Monitoring Capabilities to Study the Impact of Different Ventilatory Strategies on Brain Oxygenation During Thoracoscopic Surgery

Simultaneous Use of Masimo O3® Regional Oximetry, NomoLine® Capnography, SedLine® Brain Function Monitoring, and rainbow® Pulse CO-Oximetry Helped Clinicians Determine that Maintaining Higher End-tidal Carbon Dioxide (EtCO2) Improved Cerebral Oxygenation, Leading to Improved Outcomes

Masimo (NASDAQ: MASI) today announced the findings of a prospective, single-blinded, randomized controlled study published in the Journal of Anesthesia & Intensive Care Medicine in which Dr. Mona Mohamed Mogahed and colleagues at Tanta University in Tanta, Egypt and The King Fahd General Hospital in Jeddah, Saudi Arabia, sought to evaluate the impact of varying ventilation strategies on the cerebral oxygenation of patients undergoing video-assisted thoracoscopic surgery (VATS). To monitor the variety of physiological parameters needed to undertake such an evaluation, they turned to the multi-modal Masimo Root® patient monitoring and connectivity platform, which is designed to allow clinicians to streamline their ability to keep track of numerous modalities, simultaneously, using a single, intuitive monitor. The technologies involved included O3® regional oximetry, capnography with NomoLine® sampling lines, SedLine® brain function monitoring, and multiple rainbow® Pulse CO-Oximetry measurements. Using Root and Masimo monitoring technologies, the researchers were able to determine that maintaining higher end-tidal carbon dioxide (EtCO2) improved baseline regional cerebral oxygenation (rSO2), with impacts on early postoperative cognitive function that included improvements in Aldrete scores and mini mental status exam (MMSE) scores.1

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Masimo Root® (Graphic: Business Wire)

Masimo Root® (Graphic: Business Wire)

Noting the increased risk of hypoxemia during one-lung ventilation (OLV) as part of VATS, which can lead to postoperative neurocognitive dysfunctions, the authors hypothesized that increasing EtCO2 could be a “convenient and powerful” way to manage cerebral desaturation during the surgery. They enrolled 70 patients, ages 18-65, undergoing elective VATS requiring OLV, between September 2021 and September 2022 at The King Fahd General Hospital, Jeddah. All patients were operated on by the same surgical team. The patients were randomly divided into two groups: in the first, EtCO2 was maintained at 32-38 mmHg (group I) and in the second, at 39-45 mmHg (group II). During the procedure, monitored parameters included oxygen saturation (Masimo SET® SpO2), heart rate (HR), and noninvasive hemoglobin (Masimo SpHb®) via an RD rainbow SET® fingertip sensor; EtCO2 via capnometer and NomoLine sampling line; noninvasive blood pressure (NIBP), body temperature, and rSO2 via O3 near-infrared spectroscopy (NIRS) sensors monitoring both brain hemispheres; and Masimo Patient State Index (PSi™), a processed EEG parameter used to help clinicians maintain appropriate sedation, via SedLine. Outcomes included Aldrete scores and MMSE scores assessed at 3 and 24 hours after surgery.

The researchers found that the percentage of change in rSO2 differed significantly between groups (p < 0.05), on both sides of the brain, with the higher values, over time, in Group II, in direct relation with the higher EtCO2 maintained in that group. In the right hemisphere, the difference became significant at the fourth time interval [T4] at which rSO2 was recorded, p = 0.0012, and maintained significance for the remainder of surgery [T4-T13], p < 0.001. In the left hemisphere, the difference became significant at T2, p = 0.09, and remained significant [T3-13], p < 0.001. Aldrete scores were significantly higher in Group II upon arrival at the post-anesthesia care unit (PACU) (p = 0.013) and 15 minutes after arrival (p = 0.03), then became comparable. MMSE scores were significantly higher in Group II 3 hours after surgery (p = 0.0009), but not at 24 hours after surgery.

The researchers concluded, “Adjusting the ventilator parameters to develop EtCO2 of 39-45 mmHg improved cerebral oxygenation more than EtCO2 of 32-38 mmHg, that play[s] a protective role in the brain, causing significant impact on the early postoperative cognitive function in patients with OLV undergoing VATS.” Regarding the use of Masimo Root and associated monitoring technologies, they noted that they “preferred using it as it can display several clinical measurements [at] the same time, such as HR, BP, temperature, SpO2, EtCO2, PSi, and rSO2.”

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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.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.5-8 Masimo SET® is estimated to be used on more than 200 million patients in leading hospitals and other healthcare settings around the world,9 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.10 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 Published clinical studies on Masimo products can be found at

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.


  1. Mogahed MM, Alnoamani TS, Elkahwagy MS. The Ventilatory Influence on Cerebral Oxygenation in Patients Undergoing Video Assisted Thoracoscopic Surgery. J Anest & Inten Care Med. 12(3). December 2022. DOI: 10.19080/JAICM.202212.555837.
  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 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.
  6. Taenzer A et al. Postoperative Monitoring – The Dartmouth Experience. Anesthesia Patient Safety Foundation Newsletter. Spring-Summer 2012.
  7. 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.
  8. 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.
  9. 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 Root®, O3®, NomoLine®, SedLine®, rainbow®, RD rainbow SET®, SpHb®, SET®, and PSi™. 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 Root, O3, NomoLine, SedLine, rainbow®, RD rainbow SET, SpHb, SET®, and PSi, 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 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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