Bispectral Index Monitoring

Bispectral index is among many technologies that claim to check anesthesia depth. Bispectral index monitors are planned to substitute Guedel’s classification system for verifying anesthesia depth.


Bispectral index monitoring entails making use of an electric device which translates EEG waves into numerical figures. The number, which is based statistically on crude EEG data, signifies the level or depth of sedation of a patient and gives straight measures of sedatives and anesthetic effects on the brain. Bispectral index monitoring gives objective and reliable data where the nurse can base care from, instead of relying mainly from vital signs as well as subjective signs, and thus, pose lesser threats of both undersedation and oversedation.


The bispectral index monitor is connected to a sensor which is placed on the forehead of the patient. The sensor collects information regarding the electrical activities of the patient’s brain and interprets this data into a number starting from 0 (no brain activity) up to 100 (awake and alert). Monitoring, when on the intensive care unit, is used mainly to evaluate sedation when the patient is on mechanical ventilation, neuromuscular blockers, or when the patient is on barbiturate coma or for bedside procedures.

Equipment Needed
  • Bispectral index monitor along with cable
  • Bispectral index sensor
  • Alcohol swabs
  • Soap and water
Steps with Rationale
  1. Place the bispectral index monitor near the bed of the patient and plug the cord into the outlet on the wall.
    • Rationale: This is in preparation for the monitoring procedure, so as to save time and effort.
  2. Collect the needed equipment and verify the identity of the patient (refer to facility policy). Explain the procedure and provide rationale to the patient as well as to his family.
    • Rationale: Gathering everything needed helps to save time and effort. Verify to make sure that the right patient receives the right treatment. Explaining to the patient and to his family will help ease anxiety and promote comfort. Every patient has the right to know the treatment he receives.
  3. Provide privacy. Do handwashing.
    • Rationale: Privacy will help keep patient comfortable and will not violate his right. Handwashing helps prevent spread of infection.
  4. Cleanse the patient’s forehead using soap and water. Then allow it to dry. If needed, use alcohol swab to make sure that the forehead is free from oil. Let the alcohol dry.
    • Rationale: Forehead needs to be oil-free so that monitor sensors can stick properly.
  5. Open the sensor package. Place the sensor on the forehead of the patient. The circle with the label “1” should be placed just above the bridge of the nose (about 4 cm).
    • Rationale: Proper positioning of the sensors help prevent errors in reading.
  6. The circle with the label “3” should be on the left or right temple, just at the outer canthus of the eye, in between the hairline of the patient and the corner of the eye.
    • Rationale: Proper positioning of the sensors help prevent errors in reading.
  7. The circle with the label “4” as well as the line beneath it should be parallel to the eye on the proper side.
    • Rationale: Proper positioning helps prevent error in reading.
  8. Use gentle yet firm pressure on the sensors’ edges as well as on the areas of the labeled circles.
    • Rationale: To make sure there is proper adhesion.
  9. Firmly press on every labeled circles for about 5 seconds.
    • Rationale: To make sure that the electrodes stick to the skin.
  10. Attach the sensor to the monitor and interface cable. Switch the monitor on. Observe the monitor for signs of electrical resistance.
    • Rationale: To ensure that the equipment is working properly.
  11. Choose a smoothing rate (this is the time when data is evaluated for the calculation of the bispectral index, it usually is around 15 to 20 seconds) by making use of the “advanced setup” button depending on the policy of the facility. Read and record the bispectral index value.
    • Rationale: To be certain that procedure is done within policy. Read to get the value and record for documentation purposes.
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