Study Uses Masimo Patient SafetyNet™ and rainbow Acoustic Monitoring® to Investigate the Incidence of Desaturation and Bradypnea in Postoperative Patients

Patient SafetyNet is a supplemental remote monitoring, patient surveillance, and clinician notification system that works in conjunction with Masimo and third-party bedside monitoring devices to display near real-time data at central stations. RAM with RRa uses an acoustic transducer positioned on the patient’s neck to provide noninvasive, continuous respiration monitoring.

Hypothesizing that postoperative desaturation and bradypnea might occur even in non-ICU patients without serious complications, and in patients who did not undergo major surgery, Drs. Masashi Ishikawa and Atsuhiro Sakamoto set up a centralized postoperative monitoring system in the general ward to investigate how common these events are for such patients (and what might predict them). They analyzed demographic and monitoring data from 1,064 adult patients who underwent general anesthesia for various surgical procedures over a 4-month period. The patients were monitored using a pulse oximeter and an RRa sensor for at least 8 hours after surgery, data which were automatically transferred to Patient SafetyNet.

From the data stored on the Patient SafetyNet, the researchers were able to retrospectively analyze the incidence of desaturation (defined as SpO₂ < 90% for > 10 seconds) and bradypnea (defined as respiratory rate < 8 breaths/minute for > 2 minutes). They found that 12.1% of patients exhibited desaturation (244 events among 129 patients), with most occurring after the termination of oxygen administration, and 50.8% of the events occurring more than 8 hours after surgery. They found that 5.1% of the patients exhibited bradypnea (112 times among 54 patients), with 72.3% of the events occurring during oxygen supplementation, and with the greatest incidence within the first hour after surgery. Age, body mass index, and current smoking status were significant risk factors for desaturation. Sleep apnea syndrome and postoperative opioid administration were significant risk factors for bradypnea. Age and postoperative opioid administration were significant risk factors for the combination of desaturation and bradypnea.

The researchers concluded, “Our study suggests that use of a continuous and centralized respiratory monitoring system for overnight postoperatively is desirable for postoperative management in the general ward, which would likely improve the safety of postoperative patients, especially those with risk factors for respiratory depression.”

The researchers commented on a number of methods of respiratory rate monitoring, stating, “Continuous and centralized monitoring of oxygen saturation and respiratory rate can detect respiratory depression before it results in critical events such as cardiac arrest. Several methods of respiratory rate monitoring are currently used, including manual counting of breaths by a caregiver, capnography, and transthoracic impedance measurement. Manual counting of breaths (such as auscultation) is an intermittent, labor-intensive and unreliable method. Capnography provides accurate and continuous monitoring, but requires a nasal or facial interface, which can be uncomfortable and may lead to failure if the interface is moved. Transthoracic impedance is non-invasive and can detect respiratory efforts, but is unable to detect alveolar hypoventilation caused by airway obstruction.”^2-6

Additionally, the researchers commented on RAM with RRa, the respiratory rate monitoring method used in the current study, and referenced another study in which RRa and capnography were compared, stating: “RRa is an acoustic monitoring device that continuously measures respiratory rate, and is as accurate as capnography in extubated patients.⁷ Patient activities, such as talking, coughing and crying, affect the results of both RRa and capnography. The measurement errors during these activities are, however, not clinically relevant because they require that the patients are awake and breathing. Further, the RRa sensor appears to be well-tolerated and no more subject to error than capnography.⁷ RRa was found to be a reliable device and had fewer complications in this study.”

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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.⁸ Masimo SET^® has also been shown to help clinicians reduce severe retinopathy of prematurity in neonates,⁹ improve CCHD screening in newborns,¹⁰ and, when used for continuous monitoring with Masimo Patient SafetyNet™ in post-surgical wards, reduce rapid response team activations, ICU transfers, and costs.^11-13 Masimo SET^® is estimated to be used on more than 100 million patients in leading hospitals and other healthcare settings around the world,¹⁴ and is the primary pulse oximetry at 9 of the top 10 hospitals according to the 2019-20 U.S. News and World Report Best Hospitals Honor Roll.¹⁵ Masimo 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 www.masimo.com. Published clinical studies on Masimo products can be found at www.masimo.com/evidence/featured-studies/feature/.

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.

References

1. Ishikawa M and Sakamoto A. Postoperative desaturation and bradypnea after general anesthesia in non-ICU patients: a retrospective evaluation. J Clin Monit Comput. 2 Mar 2019. https://doi.org/10.1007/s10877-019-00293-0.
2. Petterson MT, Begnoche VL, and Graybeal JM. The effect of motion on pulse oximetry and its clinical significance. Anesth Analg. 2007;105(6 Suppl):78–84.
3. Wilkinson JN, and Thanawala VU. Thoracic impedance monitoring of respiratory rate during sedation—is it safe? Anaesthesia. 2009;64(4):455–6.
4. Cohen KP, Ladd WM, Beams DM, Sheers WS, Radwin RG, Tompkins WJ, and Webster JG. Comparison of impedance and inductance ventilation sensors on adults during breathing, motion, and simulated airway obstruction. IEEE Trans Biomed Eng. 1997;44(7):555–66.
5. Drummond GB, Nimmo AF, and Elton RA. Thoracic impedance used for measuring chest wall movement in postoperative patients. Br J Anaesth. 1996;77(3):327–32.
6. Brouillette RT, Morrow AS, Weese-Mayer DE, and Hunt CE. Comparison of respiratory inductive plethysmography and thoracic impedance for apnea monitoring. J Pediatr. 1987;111(3):377–83.
7. Mimoz O, Benard T, Gaucher A, Frasca D, and Debaene B. Accuracy of respiratory rate monitoring using a non-invasive acoustic method after general anaesthesia. Br J Anaesth. 2012 May;108(5):872–5.
8. 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.
9. 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.
10. 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.
11. 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.
12. Taenzer A et al. Postoperative Monitoring – The Dartmouth Experience. Anesthesia Patient Safety Foundation Newsletter. Spring-Summer 2012.
13. 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.
14. Estimate: Masimo data on file.
15. 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 Patient SafetyNet™ and RRa^®. 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 Patient SafetyNet and RRa, 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 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.