BIS 186-0106Recalls & reported problems

Summary

The FDA's MAUDE database contains 105 adverse event reports that list this exact device (DI 20884521134307), received between Apr 25, 2018 and Jun 23, 2026 — classified as 1 death, 4 injuries, 100 malfunctions.

The most frequently reported specific device problem is “Patient Device Interaction Problem” (39 reports).

Reports come from manufacturers, hospitals and patients and are not verified by the FDA. A report does not prove the device caused the event, and counts can't be used to compare devices or estimate failure rates. How this data works · Data updated Oct 13, 2026.

Most reported problems

Recent adverse event reports

The 25 most recent of 105 reports, in the reporter's own words as published by the FDA.

• MalfunctionJun 23, 2026Incorrect Measurement; Communication or Transmission Problem

  IT WAS REPORTED THAT DURING USE, THE WAVEFORM WAS DISORDERED AND IRREGULAR AND THE SIGNAL COULD NOT BE DETECTED NORMALLY. THE SCREEN SHOWED GARBLED CHARACTERS. THE DEVICE WAS IMMEDIATELY DISCONTINUED AND REPLACED. THERE WAS NO PATIENT HARM.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 25589852 ↗
• MalfunctionJun 20, 2026Unable to Obtain Readings; High Readings; Communication or Transmission Problem

  IT WAS REPORTED THAT THE SENSOR HAD NO READING. SENSOR NUMBER 3 WAS SPECIFICALLY REPORTED AS NOT BEING RECOGNIZED AND HAVING CONSISTENTLY HIGH READINGS. THERE WAS NO REPORTED PATIENT OUTCOME.

  Patient problems: Insufficient Information

  MAUDE report 25568991 ↗
• MalfunctionApr 16, 2026Patient Device Interaction Problem

  IT WAS REPORTER THAT THE PATIENT USED THE SENSOR FOR APPROXIMATELY THREE HOURS AND LATER DEVELOPED BRUISING ON THE FOREHEAD. ON POSTOPERATIVE DAY ONE, A 3 CM AREA OF REDNESS WAS NOTED ON THE LEFT FOREHEAD WITHOUT ITCHING OR PAIN. SHORTLY AFTERWARD, THE PATIENT REPORTED REDNESS AND PAIN IN THE LEFT FRONTAL AREA. THE ATTENDING PHYSICIAN INITIALLY PRESCRIBED LINDELON VG, WHICH WAS LATER CHANGED TO LOCOID. ON DAY TWO, THREE RAISED, 3 CM LESIONS APPEARED ON THE FOREHEAD, STILL WITHOUT ITCHING. THE PATIENT REPORTED THAT THE RASH PERSISTED AND THAT LOCOID SEEMED INEFFECTIVE. A DERMATOLOGY CONSULT WAS ARRANGED. EXAMINATION SHOWED WELL-DEMARCATED EDEMATOUS ERYTHEMA AT THREE FOREHEAD SITES AND ONE ON THE LEFT TEMPLE. DELAYED PRESSURE URTICARIA WAS SUSPECTED, AND BETASEREMIN COMBINATION TABLETS AND NERIZONA UNIVERSAL OINTMENT WERE PRESCRIBED.

  Patient problems: Bruise/Contusion

  MAUDE report 24895537 ↗
• MalfunctionMar 20, 2026Incorrect Measurement; Unable to Obtain Readings; Failure to Read Input Signal

  IT WAS REPORTED THAT DURING USE, THE DEVICE DID NOT DISPLAY A BIS READING BECAUSE THE SENSOR FAILED THE IMPEDANCE TEST AND SENSOR CHECK. THE PATIENT WAS CHEMICALLY PARALYZED AND SEDATED; THEREFORE, THE RISK OF EMG INTERFERENCE SHOULD HAVE BEEN MINIMAL. ONCE THE BIS READING WAS OBTAINED, THE BIS VALUE WAS IN THE 40S (WITHIN THE TARGET RANGE). BASED ON THIS CONDITION, THE EXPECTED OUTCOME WAS THAT THE SENSOR WOULD HAVE A HIGHER LIKELIHOOD OF PROVIDING A RELIABLE READING AND PASSING THE IMPEDANCE CHECK, WHICH WAS NOT OBSERVED IN THIS CASE. THE SKIN WAS PREPARED WITH AN ALCOHOL WIPE. A NEW SENSOR WAS THEN APPLIED; HOWEVER, IT REQUIRED AN ADDITIONAL FIVE OR MORE MINUTES AND FURTHER MANIPULATION TO PASS THE SENSOR CHECK AND OBTAIN A READING. ONCE OBTAINED, THE BIS VALUE WAS WITHIN SATISFACTORY LIMITS, THE VALUE WAS CAME FROM THE SECOND SENSOR. NO PATIENT COMPLICATIONS WERE REPORTED AS A RESULT OF THIS EVENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24651197 ↗
• MalfunctionFeb 25, 2026Incorrect Measurement

  IT WAS REPORTED THAT THE PRODUCT GAVE ERRATIC READINGS. CLINICAL ASSESSMENT WAS CONDUCTED TO CONCLUDE THAT THE VALUES WERE INCORRECT. THE SKIN WAS PREPPED WITH MEDICAL ALCOHOL PRIOR TO SENSOR PLACEMENT. NO PATIENT COMPLICATIONS HAVE BEEN REPORTED AS A RESULT OF THIS EVENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 24445658 ↗
• MalfunctionJan 21, 2026Unable to Obtain Readings

  IT WAS REPORTED THAT THE PATIENT UNDERWENT LAPAROSCOPIC EXPLORATION UNDER GENERAL ANESTHESIA. PREOPERATIVE ANESTHESIA MONITORING OF BRAIN ELECTRICAL ACTIVITY REVEALED THAT TWO LEADS COULD NOT BE CONNECTED AND NO SIGNAL WAS DETECTED. THE SENSOR WAS REPLACED AND FUNCTIONED NORMALLY. THIS DELAYED THE PATIENT'S SURGICAL TREATMENT TIME.

  Patient problems: Insufficient Information

  MAUDE report 24129830 ↗
• MalfunctionDec 20, 2025Device Alarm System; Incorrect Measurement; Device Alarm System; Incorrect Measurement

  IT WAS REPORTED THAT THE SENSORS EXPERIENCED ISSUES INTRAOPERATIVELY: THE STRIP STOPPED WORKING AND THE DEVICE INDICATED THE NEED FOR REPLACEMENT, THE MONITORING WAS NOT CONSISTENT WITH THE CLINICAL PARAMETERS OBSERVED WITH POSSIBLY INCORRECT VALUES SHOWN ON THE MONITOR, AND THERE WAS NO AUDIBLE ALARM. THERE WAS NO PATIENT INJURY.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 23858430 ↗
• MalfunctionNov 5, 2025Incorrect Measurement; Incorrect Measurement

  IT WAS REPORTED THAT THE SENSOR PRESENTED A PROBLEM WITH READING AND REQUIRED A REPLACEMENT. THERE WAS NO PATIENT INVOLVEMENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 23475435 ↗
• InjuryOct 28, 2025High Readings; Communication or Transmission Problem; High Readings; Communication or Transmission Problem

  IT WAS REPORTED THAT THE SENSOR DID NOT COMMUNICATE, AND THE PATIENT WAS UNDER GENERAL ANESTHESIA. THE ANESTHESIA DEPTH MONITOR WAS SET UP BEFORE INDUCTION. HOWEVER, BEFORE THE INCISION, IT INDICATED A VALUE OF 85, DESPITE A PROPOFOL TARGET OF 10 IN TCI MODE. THEELECTROENCEPHALOGRAM (EEG) TRACING SHOWED AN ALMOST FLAT CURVE, WHICH INDICATED A DISCREPANCY BETWEEN THE DISPLAYED VALUE AND THE TRACING. AFTER CHANGING THE SENSOR, THE SAME DATA WAS RETURNED. A THIRD SENSOR WAS THEN USED. THE EVENT RESULTED TO EXCESSIVELY DEEP ANESTHESIA AND REQUIRED CATECHOLAMINES BECAUSE OF THE ANESTHESIA DOSES GIVEN.

  Patient problems: Insufficient Information

  MAUDE report 23401442 ↗
• InjuryOct 28, 2025High Readings; Communication or Transmission Problem; High Readings; Communication or Transmission Problem

  IT WAS REPORTED THAT THE SENSOR DID NOT COMMUNICATE, AND THE PATIENT WAS UNDER GENERAL ANESTHESIA. THE ANESTHESIA DEPTH MONITOR WAS SET UP BEFORE INDUCTION. HOWEVER, BEFORE THE INCISION, IT INDICATED A VALUE OF 85, DESPITE A PROPOFOL TARGET OF 10 IN TCI MODE. THEELECTROENCEPHALOGRAM (EEG) TRACING SHOWED AN ALMOST FLAT CURVE, WHICH INDICATED A DISCREPANCY BETWEEN THE DISPLAYED VALUE AND THE TRACING. AFTER CHANGING THE SENSOR, THE SAME DATA WAS RETURNED. A THIRD SENSOR WAS THEN USED. THE EVENT RESULTED TO EXCESSIVELY DEEP ANESTHESIA AND REQUIRED CATECHOLAMINES BECAUSE OF THE ANESTHESIA DOSES GIVEN.

  Patient problems: Insufficient Information

  MAUDE report 23401428 ↗
• MalfunctionSep 17, 2025Incorrect Measurement; Incorrect Measurement

  IT WAS REPORTED THAT A NUMERICAL INACCURACY WAS IDENTIFIED WITH THE SENSOR. NO PATIENT COMPLICATIONS HAVE BEEN REPORTED AS A RESULT OF THIS EVENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 23077438 ↗
• MalfunctionJul 25, 2025Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT THE SENSOR CAUSED A SKIN ALLERGY, RESULTING IN THE PATIENT'S SKIN REMAINING RED FOR MORE THAN A WEEK. THE SENSOR WAS PLACED ON THE FOREHEAD FOR ONE TO TWO HOURS PRIOR TO THE EVENT. THE PATIENT WAS SENT TO A DERMATOLOGIST FOR TREATMENT.

  Patient problems: Erythema

  MAUDE report 22614178 ↗
• MalfunctionMay 8, 2025Incorrect Measurement; Incorrect Measurement

  IT WAS REPORTED THAT THE SENSOR'S EMG VALUE KEPT RISING EVEN THE PATIENT WAS FULLY SEDATED AND PARALYZED. THERE WAS NO PATIENT INJURY.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 21986110 ↗
• MalfunctionApr 4, 2025Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT DURING USE, THERE WERE SENSOR MARKS ON THE SIDE OF THE PATIENT'S TEMPORAL REGION, AND THEY DID NOT DISAPPEAR.

  Patient problems: Inflammation

  MAUDE report 21773728 ↗
• MalfunctionApr 4, 2025Low Readings; Low Readings

  IT WAS REPORTED THAT DURING THE USE, THE SENSOR RESULTED IN LOW READINGS WITH VALUES BETWEEN 18-22. THE SKIN WAS PREPPED WITH AN ALCOHOL PAD PRIOR TO SENSOR PLACEMENT. NO PATIENT COMPLICATIONS HAVE BEEN REPORTED AS A RESULT OF THIS EVENT.

  Patient problems: No Clinical Signs, Symptoms or Conditions

  MAUDE report 21773447 ↗
• MalfunctionApr 1, 2025Incorrect Measurement; High Readings; Incorrect Measurement; High Readings

  IT WAS REPORTED THAT INTRA-OPERATIVELY, THE SENSOR HAD HIGH READINGS OF 80-90. THE BASELINE WAS SET AT 40-60. THE SENSOR WAS REPLACED. THERE WAS NO REPORTED PATIENT OUTCOME.

  Patient problems: Insufficient Information

  MAUDE report 21738268 ↗
• MalfunctionMar 25, 2025Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT THE PATIENT EXHIBITED SWELLING AND REDNESS ON THE FACE WHERE THE PATCH WAS PLACED, THE SENSOR WAS PLACED ON PATIENT APPROXIMATELY 1.5 HOURS AND SUFFERED A TEMPORARY INJURY DUE TO THE ALLERGIC REACTION, INCLUDING ALLERGIC SHOCK. THE PATIENT SOUGHT EMERGENCY CARE TWO DAYS AFTER SURGERY DUE TO THESE ALLERGIC SYMPTOMS. THE PATIENT HAD A KNOWN ALLERGY TO THE STICKY COMPONENT OF PATCHES AND TAPE, ALTHOUGH THE SPECIFIC ALLERGEN WAS UNKNOWN. NO MEDICAL OR SURGICAL INTERVENTION WAS NEEDED TO PREVENT PERMANENT IMPAIRMENT.

  Patient problems: Skin Inflammation/ Irritation

  MAUDE report 21692807 ↗
• MalfunctionMar 24, 2025Incorrect Measurement; Incorrect Measurement

  IT WAS REPORTED THAT, DURING USE, THE VALUES MONITORED BY THE BRAIN ELECTRODE PAD HAD LARGE DEVIATIONS AND WERE INACCURATE. THERE WAS A DELAYED OF TREATMENT.

  Patient problems: Unspecified Tissue Injury

  MAUDE report 21678009 ↗
• MalfunctionMar 20, 2025Use of Device Problem; Low Readings; Use of Device Problem; Low Readings

  IT WAS REPORTED THAT POST-OPERATIVELY, THE UNIT HAD A CONNECTION MESSAGE AND HAD A VALUE OF 40-50 WHILE THE PATIENT WAS AWAKE. THERE WAS NO REPORTED PATIENT OUTCOME.

  Patient problems: Insufficient Information

  MAUDE report 21658369 ↗
• MalfunctionFeb 4, 2025Insufficient Device Problem Information; Patient Device Interaction Problem; Insufficient Device Problem Information; Patient Device Interaction Problem

  IT WAS REPORTED THAT A PATIENT EXPERIENCED A REACTION TO THE BIS SENSOR, RESULTING IN A RED, ITCHY, AND PAINFUL RASH ON THE FOREHEAD. THE RASH'S DISTRIBUTION PRECISELY MATCHED THE SHAPE OF THE SCALP ELECTRODE.

  Patient problems: Rash

  MAUDE report 21309154 ↗
• MalfunctionJan 27, 2025Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT, DURING USE, THE PATIENT PRESENTED WITH ERYTHEMA IN THE FRONTAL REGION.

  Patient problems: Pressure Sore/Ulcer

  MAUDE report 21240598 ↗
• MalfunctionJan 17, 2025Image Display Error/Artifact; Unable to Obtain Readings; Patient Device Interaction Problem; Image Display Error/Artifact; Unable to Obtain Readings; Patient Device Interaction Problem

  IT WAS REPORTED THAT POST-OPERATIVELY, THE SENSOR DISPLAYED AN ERROR MESSAGE, "UNABLE TO READ SENSOR," ON THE SCREEN, AND MEASUREMENT COULD NOT BE PERFORMED. THE SENSOR WAS WORN ON THE FOREHEAD AND CAUSED A MODERATE SKIN DISORDER.

  Patient problems: Insufficient Information

  MAUDE report 21182080 ↗
• MalfunctionJan 17, 2025Image Display Error/Artifact; Unable to Obtain Readings; Failure to Analyze Signal; Patient Device Interaction Problem; Image Display Error/Artifact; Unable to Obtain Readings; Failure to Analyze Signal; Patient Device Interaction Problem

  IT WAS REPORTED THAT POST-OPERATIVELY, THE SENSOR DISPLAYED AN ERROR MESSAGE, "UNABLE TO READ SENSOR," ON THE SCREEN, AND MEASUREMENT COULD NOT BE PERFORMED. THE SENSOR WAS WORN ON THE FOREHEAD AND CAUSED A MODERATE SKIN DISORDER.

  Patient problems: Insufficient Information

  MAUDE report 21178222 ↗
• MalfunctionJan 15, 2025Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT POST-OPERATIVELY, IN THE OPERATING ROOM, EEG MONITORING WAS PERFORMED USING THE DEVICE. AFTER SURGERY, THE SENSOR WAS REMOVED, AND UPON INSPECTING THE SKIN SURFACE OF THE FOREHEAD, IT WAS FOUND THAT TWO AREAS WHERE THE ELECTRODES HAD BEEN ATTACHED HAD BROWN STAIN-LIKE MARKS. AFTER TWO WEEKS, THE STAINS REMAINED AND DID NOT NOT DISAPPEAR. THERE WAS NO PAIN OR DISCOMFORT, AND IT DID NOT AFFECT DAILY LIFE.

  Patient problems: Skin Discoloration

  MAUDE report 21157107 ↗
• MalfunctionDec 2, 2024Patient Device Interaction Problem; Patient Device Interaction Problem

  IT WAS REPORTED THAT DURING A LEFT HUMERUS FRACTURE OPERATION, THE PATIENT WAS INJURED AND HAS A WOUND MEASURING APPROXIMATELY 4X2 CM ON THE RIGHT SIDE OF THE FOREHEAD. THERE HAS BEEN NO SUPERINFECTION OF THE WOUND, TO WHAT EXTENT A SCAR WITH COSMETIC RELEVANCE REMAINS WAS NOT YET FORESEEABLE.

  Patient problems: Skin Tears

  MAUDE report 20817823 ↗