Brain Function Monitoring


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A More Complete Picture Starts with More Complete Data

SEDLine monitor scan

About SedLine

SedLine® brain function monitoring advances neuromonitoring technologies to improve the care of patients under anesthesia or sedation. The core product is a state-of-the-art EEG-based brain function monitor. Utilising 4 channels of information, the SedLine monitor measures the effects of anesthesia and sedation by monitoring both sides of the brain’s electrical activity to enable more individualised titration and improve the care of patients under anesthesia or sedation.

In 2010, Masimo acquired SedLine, commercialised SedLine products through its worldwide distribution channels, and initiated next-generation brain function monitoring technology and product development.

EEG and Anesthesia

Quantitative EEG (QEEG) Measures of Brain Activity in Response to Sedation/Anesthesia Follow a Predictable Pattern

  • > As the brain falls asleep, EEG activity declines according to a specific, invariant pattern1
    • In general, this drop in activity begins in the frontal lobes and moves toward the back of the brain

Shifts in EEG Power at Induction and Loss of Consciousness (LOC)

Chart showing shifts in EEG power at induction and loss of consciousness

These VARETA images depict changes in Delta wave (i.e., 3 to 5 Hz) activity. Anesthesia (propofol shown here) spreads from the frontal lobes toward the back of the brain (note residual blue/white at induction). Even at LOC, the frontal lobes are more heavily anesthetised areas.

  • > When waking up, EEG activity increases across the brain in exactly the opposite sequence observed when falling asleep
  • > These activity patterns have been shown to be invariant across a range of patient types and sedative/anesthetic agents1
    • Propofol
    • Inhalation gas – Isoflurane, Sevoflurane and Desflurane
    • Nitrous/narcotic

PSI Algorithm

A Sophisticated Algorithm

The SedLine device uses a sophisticated multivariate algorithm to assess the patient’s EEG data from all 4 channels and determine the Patient State Index (PSI) value as a measure of anesthetic depth.

SedLine technology is based on more than 10 years of technical and clinical development. The algorithm is based on extensive EEG records developed by the Brain Research Laboratory at New York University School of Medicine. The sensor technology was developed to improve the acquisition of EEG signals and was used in NASA’s Sleep Studies in 1998. By providing an integrated algorithm based upon 4-channels of EEG data, demonstrated reliability under challenging clinical conditions and superior resistance to cautery, the SedLine monitor system offers a cost-effective alternative to other monitors. The system is currently in use at some of the nation’s leading healthcare institutions.

Chart illustrating the PSI algorithm

Grounded in Sound Science

The algorithm relies upon stepwise comparisons against extensive EEG records developed by the Brain Research Laboratory at New York University School of Medicine. These records encompass five databases with patient data recorded under a variety of clinical and anesthetic conditions.

Using EEG Data From Both Sides of the Brain

Multiple sub-algorithms enhance the sensitivity of PSI algorithm to changes in activity. The “arousal observer” sub-algorithm detects subtle early changes in EEG that signify decreasing sedation. This sub-algorithm also scrutinises changes in activity occurring between pairs of leads for evidence of patterns signaling waning sedation levels.

Read PSI 25-50 Range of Optimal Hypnotic State for General Anesthesia to learn more about the studies supporting the development of the algorithm.

PSI Guidelines

A Greater Volume of Data to Enhance Your Anesthetic Control

Brain function monitoring with SedLine helps the anesthesia provider deliver the desired level of targeted sedation throughout all phases of anesthesia. SedLine uses a sophisticated algorithm based on extensive EEG records to process EEG data and determine the PSI value as a measure of anesthetic depth. The PSI corresponds to a patient’s current level of sedation/anesthesia along a scale of 0 to 100, where 100 represents being fully awake2. Guidelines for interpreting the full range of values are presented below. Read PSI 25-50 Range of Optimal Hypnotic State for General Anesthesia to learn more about the studies supporting the development of these guidelines.

The PSI values reflect loss of consciousness, arousals, emergence and response to noxious stimuli. For ease in use, the numeric PSI values are colour coded on the display to promote immediate assessment of patient status. 4-channel real-time EEG data is presented as waveforms and as a Density Spectral Array (DSA) to enable quick and easy confirmation of PSI values.

Chart of guidelines for PSI values

  • 1 John ER, Prichep LS, Kox W, et al. Invariant Reversible QEEG Effects of Anesthetics. Conscious Cogn.0 2001;10:165-183.
  • 2 Prichep LS, et al. The Patient State Index as an indicator of the level of hypnosis under general anesthesia. Br J Anaesth. 2004,92:393-399. Available online at http://bja.oxfordjournals.org/cgi/content/full/92/3/393.

PDF Resources

Data Sheet
Brain Function Monitoring
Data Sheet
Root
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A More Complete Picture Starts with More Complete Data

SEDLine monitor scan

SedLine® brain function monitoring for the Root™ patient monitoring platform helps clinicians improve anesthetic management by enabling more individualized titration

  • 4 simultaneous EEG channels enable continuous assessment of both sides of the brain
  • A single sophisticated algorithm for Patient State Index (PSI) provides information about a patient’s response to anesthesia
  • Superior resistance to electrocautery minimizes signal drop out1
  • Multiple screen views expand information while enabling customization in the OR and ICU

The SedLine sensor is designed for ease in application and enhanced patient comfort while ensuring the highest quality data.

  • 4 active leads collects higher volume of data in key areas of frontal lobe
  • Streamlined design for quick and easy application with no plastic disk to press


The SedLine module easily plugs into the Root patient monitoring platform via Masimo Open Connect™ (MOC-9) ports

PDF Resources

Data Sheet
Brain Function Monitoring
Data Sheet
Root
Speaker Slides
Masimo SedLine
brain function banner

A More Complete Picture Starts with More Complete Data

SEDLine monitor scan

Anesthesia

A More Complete Picture of the Brain’s Response to Anesthesia

Brain function monitoring delivers clear, objective, real-time insight into a patient’s depth of anesthesia and sedation. To facilitate faster assessment of patient status, the SedLine monitor provides the Patient State Index (PSI), a calculated measure of brain activity that reflects the patient’s current level of sedation/anesthesia1. Visit the Technology section to learn more about how the PSI is calculated.

The goal of anesthesia during a surgical procedure—for an event-free case—is to administer a balance of drugs that achieve appropriate levels of:

  • > Areflexia (absence of movement)
  • > Analgesia (absence of pain)
  • > Loss of consciousness (sedation/hypnosis)

Anesthesia diagram

When used as an adjunct to traditional monitoring, brain function monitoring enables the anesthesia provider to deliver the desired level of targeted sedation throughout all phases of anesthesia to:

  • > Optimize anesthetic depth
  • > Enhance patient care

Geriatric patients

  • > Variable response to anesthetics
  • > Minimum alveolar concentration (MAC) of inhalation agents decreases with age
    • For every 10-year age increase, 6% decrease in MAC
  • > Increased sensitivity to opioids
    • More susceptible to overdose and slow recovery in post-anesthesia care unit (PACU)
    • Changes in hemodynamics have little to do with anesthetic depth; a more accurate reflection of patient’s baseline physiological status
  • > Brain function monitors help titrate anesthetic to keep patient in optimum range
    • Allows anesthesiologists to control changes in BP with vasoactive drugs rather than extra anesthetic
    • Facilitates reduced use of anesthetics which may influence POCD (Post operative cognitive dysfunction
  • > Brain function monitoring enables fast extubation
Dr. Terri Monk “I have found that as I have used depth of anesthesia monitoring in the operating room that the majority of the changes in hemodynamics that occur in the elderly patient during the surgical procedures have very little to do with the amount of anesthesia they are getting.”

Terri Monk, MD
Professor
Department of Anesthesiology
Duke University Medical Center
Durham, NC

Dr. David Drover “SedLine gives me a better idea of where I stand at each phase of anesthesia. The brain number helps guide me to make subtle changes in my anesthetic appropriate for the patient’s heart rate and blood pressure, and thus arrive at the end where I want to be.”

David Drover, MD
Associate Professor of Anesthesia
Stanford University Hospital
Stanford, CA

Morbidly obese patients

  • > Difficult to intubate and secure patient’s airway
  • > Drugs distributed differently
    • Fat layers store anesthesia and can result in over- or under-anesthetizing patient
  • > Postoperatively, patients recover differently from anesthesia
  • > Brain function monitors should be used throughout anesthetic process to help better judge amount of induction agent
  • > During maintenance phase, brain function monitoring facilitates individualized titration and can minimize amount of anesthesia administered
Dr. Martin Allard “Adequate monitoring and the use of SedLine and cerebral function monitoring, I believe, is important in these patients. It should be started before we begin the anesthetic and then utilized throughout the time that one does so.”

Martin Allard, MD
Professor of Anesthesiology
Dir. of anesthesia Research
Loma Linda University
Medical Center

Loma Linda, CA

Ventilated ICU patients

  • > Still struggling to properly sedate ventilated patients in the ICU
  • > Most patients are over-sedated, resulting in increased time spent on ventilation with a prolonged stay in the ICU and increased costs
  • > Goal is to more tightly control sedation to avoid these negative outcomes
  • > Brain function monitoring is a functional tool in the ICU that may help to reduce:
    • Costs
    • Morbidity
    • Length of stay in the ICU
Dr. Michael Ramsay “We need much better monitors of the brain and to use these monitors of the brain. I think this is the advantage that SedLine brings to you is that it doesn’t just look at one little area of the brain. It looks at both sides of the brain.”

Michael Ramsay, MD
Chairman
Dept. of Anesthesiology
Baylor University Medical
Center

Dallas, TX

ICU Sedation

Accurately assessing level of sedation in ICU patients has been a challenge. The effectiveness of using physiologic measures such as vital signs or response to stimulation is compromized by the presence of other drugs. Monitoring sedation through the use of sedation assessment scales is limited to single point measures in time. Further, the accuracy of sedation assessment scales may be compromized by subjectivity and inter-rater variability.

Correlation Between PSI and Ramsay Sedation Scale (RSS)

A strong correlation between the PSI values and the Ramsay Sedation Scale (RSS) as demonstrated in a recent study2 provides the opportunity to effectively manage sedation and analgesia in an objective, consistent manner across the continuum of care, especially in intubated, ventilated ICU patients. Further, changes in the PSI in response to clinical events provide an early warning for patient safety as highlighted in a recent review of sedation measures in the ICU3.

By enabling a more accurate assessment of a patient’s level of sedation, SedLine helps the clinician to maintain sedation levels within the target range.

This may help add value to patient care by contributing to:

  • Improved patient safety
  • Optimized medication levels
  • Reduced ventilator days
  • Reduced cost

graph showing PSI vs RSS

“As this technology gets better, as we have with the SedLine – easy to apply, fewer artifacts – this now becomes a functional tool to correctly control our sedation levels and reduce costs in our ICU, reduce morbidity in our ICUs and reduce stay in our ICUs.”

Michael Ramsay, MD, Chairman, Department of Anesthesiology
Baylor University Medical Center, Dallas, TX

  • 1 Prichep LS, Gugino LD, John ER, et al. The Patient State Index as an indicator of the level of hypnosis under general anesthesia. Br J Anaesth. 2004,92:393-399. Available online at http://bja.oxfordjournals.org/cgi/content/full/92/3/393.
  • 2 Schneider G, Heglmeier S, Schneider J, et al. Patient State Index (PSI) measures depth of sedation in intensive care patients. Intensive Care Med. 2004,30:213-216. Abstract available online at http://www.ncbi.nlm.nih.gov/pubmed/14673519.
  • 3 Sessler CN, Grap MJ and Ramsay AE. Evaluating and monitoring analgesia and sedation in the intensive care unit. Critical Care 2008, 12(Suppl3):S2. Available online at http://ccforum.com/content/12/S3/S2.

PDF Resources

Data Sheet
Brain Function Monitoring
Data Sheet
Root
Speaker Slides
Masimo SedLine

Additional Resources