Brain Function Monitoring

A More Complete Picture Starts with More Complete Data

SEDLine monitor scan

About SedLine

SedLine® brain function monitoring for Root® provides four simultaneous EEG channels to enable continuous assessment of both sides of the brain. The Patient State Index provides information about a patient’s response to anesthesia. Instantly interpretable, high-visibility display of Masimo’s breakthrough rainbow® and SET® measurements is made possible by Masimo’s Radical-7® handheld monitor.

EEG and Anesthesia

Quantitative EEG (QEEG) Measures of Brain Activity in Response to Anesthesia

  • > As the brain falls asleep, EEG activity declines according to a specific, invariant pattern1
  • > 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)

  • > 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 agents2
    • Propofol
    • Inhalation gas - Isoflurane, Sevoflurane and Desflurane
    • Nitrous/narcotic


  • 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
  • 3 Prichep LS, John ER, Gugino LD, Kox W, Chabot RJ. Quantitative EEG assessment of changes in the level of sedation/hypnosis during surgery under general anesthesia. In: Jordon C. Memory and Awareness in Anesthesia IV. London: Imperial College Press, 2000:97-107.
  • 4 Prichep LS, Gugino LD, John ER, et al. The Patient State Index as an indicator of the level of hypnosis under general anaesthesia. British Journal of Anaesthesia. 2004;92(3):393-399.
  • 5 Gugino LD, Chabot RJ, Prichep LS, John ER, Formanek V, Aglio LS. Quantitative EEG changes associated with loss and return of consciousness in healthy adult volunteers anesthetized with propofol or sevoflurane. British Journal of Anaesthesia. 2001;87(3):421- 428.
  • 6 Gugino LD, Chabot RJ, Aglio LS, Prichep LS, Formanek V. Patient State Index assesses arousal level. Anesthesiology . 2001; 95:A282.


Product Information
Brain Function Monitoring
Product Information

Caution: Federal (USA) law restricts this device to sale by or on the order of a physician. See instructions for use for full prescribing information, including indications, contraindications, warnings, and precautions.