MAUDE Adverse Event Report: MEDTRONIC MINIMED GUARDIAN 3 SENSOR; SENSOR, GLUCOSE, INVASIVE

Device Problems Application Program Problem: Power Calculation Error (1473); Calibration Problem (2890)

Patient Problem Hypoglycemia (1912)

Event Date 04/25/2020

Event Type  Injury  

Event Description

I am a type 1 diabetic and am using a medtronic 670g pump and the guardian 3 sensors to control the insulin delivery.The system has improved my hba1c considerably over the previous methods, however there is one fault in the programming that has caused me to have a number of hypos over the last three months, and in many instances where the pump delivered insulin when the bgl was close to the safe minimum.I have circled when the insulin has been injected.Today it stopped giving insulin about 2:30 when the bg was 6.Just one hour later when it had dropped to 5.0, it asked for a bg and pumped in microboluses for an hour ( a total of about 1ml which should drop by the bg 3 mmo) and stopped when it was 4.4.My bg dropped to 3.6.I awoke having a hypo.This is one of the worst instances.It seems to happen only one a fortnight however, there have been 4 similar instances of the past week.If the pump is interpreting the sensor readings correctly, this is barely a serious problem but i have instances where the pump is out of calibration by 1mmo.If it is low, again no pump but once it was high by 1.2 and drove my bg to 2.9.It mainly happens at night but i have had one occasion during the day when i was awake.I have had a number of representations to medtronic over a year and they defend the system, and they have no answer to how this can be fixed.The people i spoke to did not think they could get any action of getting the pump reprogrammed, so i am writing to you to get the problem fixed or the product recalled.The pump is set to suspend on a low of 5 mmo; however, this does not work correctly and it still injects insulin.This risk is increased because of the inaccuracy of the sensor.Sometimes it is out by 2 or 3 mmo.A few mornings back it showed 6.8 and it was in fact 3.9 and i was having a hypo.This is extreme.I would say that 90% of the time it is spot on and maybe once a week it is out by about 2 mmo.If the pump didn't deliver below 5mmo, this wouldn't matter.There is "suspend on low" feature which is set to on but it doesn't work.Medtronic thought that this doesn't work in auto mode; fortunately i have been waking up when my bgl gets too low but i am aware that some people just go into a diabetic coma.This is a significant safety risk and could easily cause a fatality.Since i wrote the above i have had 2 long discussions with medtronic reps.They had all sorts of reasons why this was ok, ie target range is 3.9 to 8 although target is actually 6.7.Both eventually admitted that this is an issue and they would report it.If you could accelerate the process this would be good, as hypos are unhealthy and some people go straight into a coma, could die.It is easy to fix in my opinion.They could program the "suspend on low" to work on auto, or they could lift the lower target to 5.0 to allow for the inaccuracy of the sensor, or they could program the pump to have higher target.I have a number of other day reports however, today's was the most significant.Fda safety report id# (b)(4).

• Brand Name: GUARDIAN 3 SENSOR
• Type of Device: SENSOR, GLUCOSE, INVASIVE
• Manufacturer (Section D): MEDTRONIC MINIMED
• MDR Report Key: 10009047
• MDR Text Key: 189470911
• Report Number: MW5094298
• Device Sequence Number: 2
• Product Code: MDS
• Combination Product (y/n): N
• Reporter Country Code: AS
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Voluntary
• Reporter Occupation: Patient
• Type of Report: Initial
• Report Date: 04/25/2020
• 2 Devices were Involved in the Event: 1 2

1 Patient was Involved in the Event

• Date FDA Received: 04/28/2020
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: No Information
• Was Device Evaluated by Manufacturer?: No Information
• Type of Device Usage: N
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 76 YR
• Patient Weight: 80