O3™ Regional Oximeter 9637Recalls & reported problems
Masimo Corporation · Class 2
Data updated Oct 16, 2026 from official FDA records · Editorial policy
Quick summary
This Masimo O3 Regional Oximeter 9637 is a module that measures regional oxygen saturation during surgery. The 30 reports mostly describe readings that were wrong or impossible — too high, too low, or cutting out mid-procedure — plus two reports of the device heating up. No deaths and no injuries were reported, and none of the reports describe harm to patients. No recalls name this device.
AI-generated from the FDA records on this page and checked automatically against the numbers below. Read the details before relying on it.
- Adverse event reports
- 31
- Deaths reported
- 0
- Injuries reported
- 0
- Recalls naming it
- 0
Summary
The FDA's MAUDE database contains 31 adverse event reports that list this exact device (DI 00843997010771), received between Mar 11, 2018 and Sep 29, 2026 — classified as 31 malfunctions.
The most frequently reported specific device problem is “Incorrect Measurement” (17 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. What reports can and can't tell you · How this data works · Data updated Oct 16, 2026.
Reports received per month
Most reported problems
Device problems
- Incorrect Measurement17
- Sensing Intermittently7
- High Readings5
- Low Readings2
- Thermal Decomposition of Device2
- Device Displays Incorrect Message1
Patient problems
- No Consequences Or Impact To Patient25
- No Clinical Signs, Symptoms or Conditions6
Recent adverse event reports
The 25 most recent of 31 reports, in the reporter's own words as published by the FDA.
MalfunctionSep 29, 2026Incorrect Measurement; High Readings
The customer reported that the "Module measured high". There was no patient impact or consequence reported.
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 50927218 ↗MalfunctionSep 28, 2026Incorrect Measurement
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 50926712 ↗MalfunctionJun 30, 2022High Readings; High Readings
THE CUSTOMER REPORTED HIGH VALUES ON SCREEN. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 14881564 ↗MalfunctionJun 30, 2022High Readings; High Readings
THE CUSTOMER REPORTED HIGH VALUES ON SCREEN. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 14881443 ↗MalfunctionSep 27, 2021Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED THE DEVICE SHOWS IMPOSSIBLE VALUES. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 12537481 ↗MalfunctionJul 15, 2021Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED THAT THE O3 MODULE PROVIDED INACCURATE RSO2 READINGS. NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Clinical Signs, Symptoms or Conditions
MAUDE report 12178178 ↗MalfunctionAug 4, 2020High Readings; High Readings
THE CUSTOMER REPORTED HIGH RSO2 READINGS. NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 10364408 ↗MalfunctionAug 8, 2019Low Readings; Low Readings
THE CUSTOMER REPORTED THAT THE DEVICE PROVIDED LOW READINGS. NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8876431 ↗MalfunctionJul 3, 2019Sensing Intermittently; Sensing Intermittently
THE CUSTOMER REPORTED THE O3 MODULE EXPERIENCING DATA CUTOUTS DURING PROCEDURE. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8759500 ↗MalfunctionMay 28, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED INACCURATE VALUES DURING A LUNG TRANSPLANT, A DIFFERENCE WAS SEEN BETWEEN THE LEFT AND THE RIGHT SO2. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8646223 ↗MalfunctionMay 17, 2019Incorrect Measurement; Sensing Intermittently; Incorrect Measurement; Sensing Intermittently
THE CUSTOMER REPORTED WHEN THE O3 MODULE IS CONNECTED AND IN USE THE READINGS ARE DROPPING OUT AND INTERMITTENT. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8620038 ↗MalfunctionMay 15, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED INACCURATE O3 READINGS. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8612210 ↗MalfunctionMay 1, 2019Sensing Intermittently; Sensing Intermittently
THE CUSTOMER REPORTED THE O3 LEFT SIDE MEASUREMENT ARE RANDOMLY DROPPING DOWN WITHOUT CLINICAL REASON AND PORT 1 OF THE MODULE IS NOT PICKING UP AND READING "SENSOR INITIALIZING". NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8571399 ↗MalfunctionApr 25, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED THAT THE MODULE DIDN'T WORK. THE MODULE WAS RETURNED FOR EVALUATION AND IT WAS DETERMINED THAT THE MODULE HAD CONTAMINATION WHICH RESULTED IN INACCURATE MEASUREMENTS. NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8553081 ↗MalfunctionApr 23, 2019Thermal Decomposition of Device; Thermal Decomposition of Device
IT WAS REPORTED THAT "2 O3 MODULES FOUND WITH HEAT DAMAGE TO THE SENSOR CONNECTIONS." NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8539890 ↗MalfunctionApr 23, 2019Thermal Decomposition of Device; Thermal Decomposition of Device
IT WAS REPORTED THAT "O3 MODULES FOUND WITH HEAT DAMAGE TO THE SENSOR CONNECTIONS." NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8539885 ↗MalfunctionApr 16, 2019Incorrect Measurement; Device Displays Incorrect Message; Incorrect Measurement; Device Displays Incorrect Message
THE CUSTOMER REPORTED: "O3 LEFT SIDE MEASUREMENT DROPPING DOWN WITHOUT CLINICAL REASON, AND RANDOMLY. PORT 1 OF O3 MODULE IS NOT PICKING UP AND READING SENSOR INITIALIZING". NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8519012 ↗MalfunctionApr 3, 2019Sensing Intermittently; Sensing Intermittently
THE CUSTOMER REPORTED THE O3 MODULE CONNECTOR 2 DYSFUNCTION AFTER 5 MINUTES OF MEASUREMENT. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8480730 ↗MalfunctionMar 26, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED ACCURACY ISSUES WITH THE DEVICE. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED. PER THE REPORTED ISSUE, DURING OPENING OF THE STERNUM THERE WAS NO VALUE MEASUREMENT OF O3 FOR 1 MINUTE. AFTER THAT THE R 37% AND L 17% DELTA OF 20% BETWEEN L AND R. DELTA REMAINS THE SAME FOR 15 MINUTES THAN DECREASES TO 10% FOR 10 MINS. AFTER THAT GRADUALLY INCREASING OF DELTA AGAIN WHERE L GOES DOWN TO 0% AND RIGHT TO 30%. DURING PROCEDURE THE VALUES REMAIN LOW R 40% AND L 20-30%. MEDICAL MANAGEMENT WAS ADJUSTED ACCORDINGLY TO O3 VALUES, MORE INOTROPES WERE GIVEN. TEMP DURING SURGERY 35-36 DEGREES CELSIUS.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8453407 ↗MalfunctionMar 26, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED ACCURACY ISSUES WITH THE DEVICE. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED. PER THE CUSTOMER: 2HRS IN SURGERY: PERFUSION START AND COOLING DOWN, GRADUALLY DECLINING VALUES. AFTER 1 HR SELECTIVE CEREBRAL PERFUSION BOTH SIDES OF BRAIN TEMP 36.9. 22 MINS LATER SELECTIVE BRAIN PERFUSION STOPPED. THEN THE DELTA BETWEEN L AND R INCREASES TO 15-20% LEFT 18% RIGHT 33%. EEG VERY LOW ACTIVITY/ALMOST ABSENT (BURST SUPPRESSION (PSI 0-1), MEDICAL MANAGEMENT ADJUSTED ACCORDINGLY. IT WAS EXPECTED THAT RSO2 WOULD INCREASE WITH LOW BRAIN ACTIVITY DUE LOWER O2 CONSUMPTION. BECAUSE THAT DIDN¿T HAPPEN, THE BRAIN PERFUSION WAS INCREASED FROM 650 ML/MIN 750ML/MIN. VALUES REMAINED THE SAME. BLOOD GAS SHOWED NORMAL PAO2 LEVELS, HIGH SATURATION 98%. NEXT STEP WAS RBC WAS GIVEN AND CO2 WAS INCREASED ON HEART LUNG MACHINE TO OPTIMIZE OXYGENATION OF THE BRAIN. NONE OF THESE INTERVENTIONS HAD EFFECT ON THE VALUES OF O3. TEMP DURING THIS WAS AROUND 26 DEGREES. O3 L SENSOR REPLACED BY NEW ONE, CAUSED SHORT INCREASE OF 7% BUT DROPPED TO 18% SOON AFTER. INVOS CONNECTED INSTEAD OF O3, SHOWED VALUES OF AROUND 50% WITH SMALL DELTA BETWEEN LEFT AND RIGHT. LEFT WAS CHANGED BACK TO O3, WITH I
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8453374 ↗MalfunctionMar 26, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED ACCURACY ISSUES WITH THE DEVICE. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED. PER THE CUSTOMER: 15 MIN INTO SURGERY: REPOSITION HEAD TO LEFT L 30% R 50% AFTER FEW MINS HEAD WAS TURNED IN STRAIGHT POSITION BUT THE DIFFERENCE OF 20-25% BETWEEN LEFT AND RIGHT STAYS. AFTER INITIALIZATION OF PERFUSION (HEART LUNG MACHINE) PATIENT AT 35 DEGREES CELSIUS THE DIFFERENCE BETWEEN LEFT AND RIGHT TO 40%. LEFT BELOW 30% RIGHT AROUND 60%. LEFT AT ONE POINT EVEN DOWN TO 5%. DURING PERFUSION L 20% RIGHT 60% DIFFERENCE IS 40%. AT END OF PERFUSION DIFFERENCE INCREASES LEFT GOES DOWN TO 10- 20%. RIGHT STAYS THE SAME DURING ENTIRE OR (AROUND 60%). AFTER OR PATIENT NO NEUROLOGICAL DAMAGE. SURGICAL PLAN WAS ADJUSTED ACCORDING TO WHAT O3 SHOWED (AMONG OTHER FACTS), DURING PERFUSION AN AORTIC CROSS CLAMP WAS NOT USED (WHILE IT USUALLY WOULD HAVE BEEN).
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8453337 ↗MalfunctionFeb 13, 2019Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED THE DEVICE IS PROVIDING INCORRECT READINGS. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8337363 ↗MalfunctionDec 10, 2018Low Readings; Low Readings
THE CUSTOMER REPORTED THE O3 OXIMETER IS GIVING LOW RSO2 VALUES. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8146667 ↗MalfunctionNov 28, 2018Sensing Intermittently; Sensing Intermittently
THE CUSTOMER REPORTED THE MODULE WAS PLUGGED INTO MOC-9 AND NOT DISPLAYING ANYTHING ON ROOT MONITOR. ALSO ON PREVIOUS OCCASION STOPPED DISPLAYING DURING SURGERY. NO PATIENT IMPACT OR CONSEQUENCES WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 8113792 ↗MalfunctionSep 27, 2018Incorrect Measurement; Incorrect Measurement
THE CUSTOMER REPORTED THAT THE, "END-USER SAID THE RSO2 VALUE WASN'T CORRECT." NO CONSEQUENCES OR IMPACT TO PATIENT WERE REPORTED.
Patient problems: No Consequences Or Impact To Patient
MAUDE report 7916659 ↗
Other Oximeter devices
- Trilogy Trilogy100 Ventilator, InternationalRespironics, Inc. · Oximeter8 deaths2,493 reports
- Trilogy Trilogy 202 Ventilator, United StatesRespironics, Inc. · Oximeter2 deaths1,594 reports
- HAMILTON-G5 159001Hamilton Medical AG · Oximeter18 deaths1,440 reports
- Trilogy Trilogy100 Ventilator, GermanyRespironics, Inc. · Oximeter696 reports
- Model EMV+ Vent, Army, MRI 799-EMVP-04Zoll Medical Corporation · Oximeter1 death605 reports
- Trilogy Evo, O2, Japan JP2100X16BRespironics, Inc. · Oximeter4 recalls5 deaths342 reports
- Model EMV+ Vent, Army, COMMERCIAL 799-EMVP-01-01Zoll Medical Corporation · Oximeter1 death497 reports
- HAMILTON-G5 159002Hamilton Medical AG · Oximeter3 deaths451 reports
Sources and updates
- Device record: FDA GUDID, file dated Oct 13, 2026 · View this device in AccessGUDID ↗
- Adverse event reports: FDA MAUDE, file dated Oct 14, 2026 · each report above links to its original FDA record
- Recalls: FDA Medical Device Recalls, file dated Oct 16, 2026
- Page last rebuilt: Oct 16, 2026. Data downloaded through openFDA, which notes it is not validated for clinical or regulatory use.
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