Description of Event or Problem · 0
DEVICE: DEXCOM G7 CONTINUOUS GLUCOSE MONITOR MANUFACTURER: DEXCOM, INC. TYPE OF EVENT: DEVICE MALFUNCTION -- SEVERE INACCURACY AFFECTING INSULIN-DOSING SAFETY IMAGE REFERENCE: DEXCOM G7 STARTUP SCREENSHOT (UPLOADED IN REPORT) SUMMARY OF THE ISSUE DEXCOM G7 SENSORS REPEATEDLY SHOW SIGNIFICANT ACCURACY FAILURES FAR OUTSIDE THE PUBLISHED MARD. INACCURACIES COMMONLY EXCEED 30¿50 MG/DL, SOMETIMES MORE. ERRORS OCCUR ACROSS MULTIPLE SENSORS AND THROUGHOUT THE SENSOR LIFE CYCLE. CALIBRATIONS FREQUENTLY FAIL, ARE IGNORED, OR RESULT IN FURTHER DRIFT. THESE INACCURACIES DIRECTLY IMPACT INSULIN DOSING AND AUTOMATED INSULIN DELIVERY VIA THE OMNIPOD 5 SYSTEM. SENSOR START-UP ERROR, IMMEDIATELY AFTER THE REQUIRED WARM-UP PERIOD, THE G7 REPORTED A GLUCOSE VALUE OF 225 MG/DL. A CONFIRMATORY FINGERSTICK AT THE SAME MOMENT SHOWED 125 MG/DL -- A 100-POINT DISCREPANCY. THE UPLOADED DEXCOM GRAPH CLEARLY SHOWS AN UNREALISTIC AND RAPID FALSE RISE IMMEDIATELY UPON WARMUP, BEFORE ANY PHYSIOLOGICAL CHANGE WOULD BE POSSIBLE. THIS REPRESENTS A MAJOR MALFUNCTION BECAUSE G7 IS AN ICGM CLEARED FOR INSULIN DOSING. DETAILED PATTERN OF INACCURACIES LARGE ERRORS OFTEN BEGIN RIGHT AFTER SENSOR STARTUP. SENSOR VALUES FREQUENTLY DRIFT AWAY FROM ACTUAL BLOOD GLUCOSE OVER TIME. SOME SENSORS REMAIN INACCURATE FOR MANY HOURS OR MULTIPLE DAYS AND REQUIRE SUBSTITUTION OF NEW SENSOR. INACCURACIES OCCUR DURING PERIODS OF BOTH STABILITY AND CHANGE IN BLOOD GLUCOSE. REPEATED FINGERSTICKS CONFIRM THAT THE CGM VALUES ARE NOT PHYSIOLOGICALLY PLAUSIBLE. CALIBRATION ISSUES CALIBRATION ENTRIES ARE OFTEN REJECTED OR "NOT USED" BY THE SYSTEM. WHEN CALIBRATIONS ARE ACCEPTED, THE SENSOR SOMETIMES BECOMES MORE INACCURATE, NOT LESS. FREQUENT CALIBRATIONS REQUIRED TO MAINTAIN SAFETY DEFEATS THE PURPOSE OF A FACTORY-CALIBRATED CGM. IMPACT ON INSULIN DELIVERY (OMNIPOD 5 AID SYSTEM) DEXCOM G7 INACCURACIES DIRECTLY CAUSE INCORRECT AUTOMATED INSULIN DELIVERY: FALSE LOWS, INAPPROPRIATE BASAL REDUCTIONS, HYPERGLYCEMIA FALSE HIGHS, UNNECESSARY CORRECTIONS, HYPOGLYCEMIA RISK AUTOMATED MODE DECISIONS BECOME UNRELIABLE WHEN CGM VALUES ARE INCORRECT. I HAVE HAD TO TEMPORARILY EXIT AUTOMATED MODE TO MANUALLY PREVENT DANGEROUS INSULIN DOSING. MULTIPLE CORRECTIVE FINGERSTICKS AND MANUAL CORRECTIONS HAVE BEEN REQUIRED. CLINICAL & SAFETY RISKS RISK OF SEVERE HYPOGLYCEMIA IF CGM FALSELY REPORTS ELEVATED VALUES. RISK OF PROLONGED HYPERGLYCEMIA IF CGM FALSELY REPORTS LOW VALUES. INCREASED RISK WHEN THE ALGORITHM IS MAKING INSULIN DECISIONS BASED ON MARKEDLY INACCURATE DATA. REPEATED SENSOR FAILURES INCREASE PATIENT BURDEN AND REQUIRE CONSTANT VIGILANCE. FREQUENCY THESE EVENTS HAVE OCCURRED ACROSS MANY SENSORS, NOT AN ISOLATED BATCH. PROBLEMS RECUR DESPITE PROPER SITE ROTATION, INSERTION TECHNIQUE, DEVICE HANDLING, AND REPLACEMENT. OUTCOME REQUIRED CONFIRMATORY FINGERSTICKS TO DETECT DISCREPANCIES. REQUIRED MULTIPLE CORRECTION BOLUSES. REQUIRED DISABLING AUTOMATED INSULIN DELIVERY TEMPORARILY. REPEATED CUSTOMER SUPPORT CALLS AND SENSOR REPLACEMENTS. ONGOING RISK OF UNSAFE INSULIN THERAPY IF THE ISSUE CONTINUES. ADDITIONAL NOTES CLEARLY DEMONSTRATES THE STARTUP FAILURE AND THE IMMEDIATE, UNREALISTIC, SHARPLY RISING VALUES THAT OCCURRED DESPITE A CONFIRMED FINGERSTICK GLUCOSE OF 125 MG/DL. THIS FAILURE MODE IS DANGEROUS FOR USERS RELYING ON THE DEXCOM G7 FOR DOSING AND FOR CLOSED-LOOP INSULIN DELIVERY SYSTEMS. REPEATED FINGERSTICK ANALYSIS OF BLOOD GLUCOSE WITH CERTIFIED GLUCOMETER.