Medtronic Insulin Pumps

770G Overview 

The Medtronic 770G insulin pump was approved by Health Canada in December, 2020 and will soon be available in Canada (first quarter 2021).

• The 770G will be upgradeable via software.
• The pump and transmitter are both new.
• The glucose sensor (Guardian Sensor 3) is the same as used with 670G. It requires twice daily calibrations.
• The pump and new transmitter will communicate to each other and to a MiniMed Mobile phone app via Bluetooth.
• Data will be visible on the app and will be uploaded to Carelink (cloud server) automatically. The app will not program the pump.
• As per Medtronic's previous pump model, the option exists to use suspend-before-low or in addition to that, to allow for more automated insulin adjustments (e.g. AutoMode). 
• Carb counting and manual meal bolusing are required. 
• For more information visit Medtronic. 
• Consideration: If A1c prior to the start of using a hybrid closed loop (HCL) could drop quickly by more than 2% over 3 months (particularly for those with A1c in double digits), consider discussions with the specialist physican and patient about higher temporary glucose targets. Rapid A1c improvements have been associated with changes in retinopathy and rarely, painful treatment induced neuropathy of diabetes (TIND) or insulin edema.

670G Overview 

The Auto Mode feature of the Medtronic 670G pump automatically adjusts basal insulin every 5 minutes.  "Setting" basal insulin profiles by missing meals is not required because:

• Auto Mode feature functions like a “dimmer switch”. It turns basal insulin up, down or off to attempt to maintain a target of 6.7 mmol/L (before and after meals). A temporary target of 8.3 mmol/L may be programmed by the pump user.
• Medtronic's proprietary (and unseen) algorithm uses recent and past glucose readings to determine basal insulin needs.
• The basal insulin provided is different every day. There will be times the patient receives no (zero) basal insulin. See here. 

The Auto Mode feature makes suggestions for correction insulin and meal bolus insulin. Patients must still accurately count carbohydrate and program into the pump. The pump's bolus advice for meals and corrections can be accepted or declined by the paitent. However, it cannot be modified. 

Auto Mode Features Available for Use

In Auto Mode, patients will only be able to control the:

• Active insulin time
• Carbohydrate ratio
• Glucose target (6.7 mmol/L, 8.3 mmol/L)

The following are NOT available for use in Auto Mode (they are available in Manual Mode):

• Temporary basal
• Insulin sensitivity factor - ISF (The algorithm determines a correction dose based on recent insulin delivery, not on ISF. The patient may accept or decline the dose.)
• Dual or square wave bolus
• Pre-set boluses
• Easy bolus
• Manual bolus
• Remote bolus

Additional Auto Mode information:

• Auto Mode requires regular blood glucose calibrations of CGM and additional blood glucose tests when the pump requests.
• The pump can exit out of Auto Mode under certain conditions. In this case, the pump will use "Safe Basal."
• Safe Basal is an automatic function. It is a constant basal rate based on recent insulin delivery history. No automatic adjustment of basal rates is done in Safe Basal and the sensor glucose data is not used. Safe Basal allows the user time to take the actions needed to resume Auto Mode (eg. input a blood glucose reading). If actions aren't taken to resume Auto Mode, then after 90 minutes of Safe Basal the pump will return to Manual Mode (e.g. it will function like a normal pump using programmed pump basal settings).
• Although Auto Mode delivers a different amount of basal insulin each day, periodically the manual basal rates should be updated to reflect the overall pattern of recent Auto Mode basal insulin delivery as seen in Carelink reports.