Paediatric Diabetes: Guide to Using the Medtronic 780G Closed Loop System

Patient Information leaflets

Guide to Using the Medtronic 780G Closed Loop System

This information is a guide to help you start to get the best out of your pump. You may find that you need to adapt these suggestions for your own specific use. It cannot cover every situation so seek advice if you are unsure.

Top tips:

  • Bolus before eating.
  • Avoid manual corrections.
  • Only use healthy sites.
  • Suspend your pump if disconnected.
  • Avoid over-treating hypos.

If the glucose level is rising unexpectedly or not coming down promptly THINK CANNULA.

Remember there is often nothing to see and no pump alarm even when the cannula has stopped working. 

Hypoglycaemia 

Your pump will now adjust the background insulin based on your sensor glucose to try and prevent low glucose levels. It cannot however remove any bolus insulin already given or make huge adjustments if your sensitivity to insulin changes a lot. 

Possible Causes 

  • Overestimation of carbohydrate. 
  • Carbohydrate ratio too strong — look out for the basal insulin suspending soon after the bolus.  
  • Late bolusing — the pump will already have increased the basal rate so you end up with too much. 
  • Giving a manual bolus on top of an increasing basal rate — try and be patient and avoid giving manual boluses. 
  • Exercise — remember to use a temporary target.        

Management 

The amount of glucose you need is likely to be much less than you are used to but will depend on how much active insulin you have. If it is within two hours of your last bolus you will need more treatment than if it is more than three hours since your last bolus. 

  • If you are using a closed loop pump for the first time, start with half your usual hypo treatment.
  • If you are having rebound high glucose levels then consider a quarter treatment if only one down arrow or half if two/three down arrows.
  • Learn from experience. 

Exercise                                                                             

The best way to manage exercise depends on lots of things including what exercise you are going to do, how long for, how hard you are going to push yourself. You may wish to discuss your plan in detail with the team. Any plan you make should be reviewed after you have tried it a couple of times. 

As a general plan: 

  • If you are eating within two hours of planned activity and you expect that your glucose will drop: reduce the bolus with the meal before. Start by reducing by half of the amount used on non-closed loop and review. For example, if usually reduce by 50% then try 25% reduction.
  • Put on a temporary target 90 minutes before planned activity.
  • Avoid having extra carbohydrate before activity unless glucose is below 7mmols AND down arrows (otherwise the rise in glucose leads to more insulin being given).
  • Trickle in carbohydrate during activity if needed to prevent hypos - small amounts of refined carbohydrate e.g. sugary sweets or glucose-containing drink.
  • During prolonged activity eg long walk, reduce the bolus with each meal during the activity.
  • Reduce the bolus with the meal after significant exercise. Start with half of the reduction used on non-closed loop therapy.
  • Continue the temporary target longer after significant exercise. Overnight may be needed. 

If you need a large reduction in insulin the pump may not be able to do this. Come out of auto mode and run in manual mode with a temporary basal rate. 

Alcohol 

  • Do not bolus for any carbohydrate in the alcoholic drink. 
  • Do bolus for any carbohydrate in foods eaten. This is different to what you may have done in the past but the pump will increase your insulin after eating if you do not bolus.         
  • Use a temporary target overnight. This makes your pump give less insulin and aim for a higher glucose level which should protect you from low glucose levels overnight. 

Different insulin requirements with menstrual cycle (your period)      

  • Allow the pump to adjust insulin automatically and review what happens. For most people the pump will be able to handle this without you needing to change anything. 
  • If you are finding that your glucose levels are still running too high or low then come out of auto mode and run in manual mode with a temporary basal rate. 

Illness with increased insulin requirement and NO KETONES 

  • Allow the pump to adjust insulin automatically and review what happens. 
  • Consider whether your cannula needs changing. 
  • If you are finding that your glucose levels are still running high then come out of auto-mode and run in manual mode with an increased temporary basal rate. 
  • Follow usual sick day rules. 

Illness with increased insulin requirement AND KETONES >0.6mmol/l 

  • Come out of auto mode. 
  • Give fast acting insulin with a pen based on usual sick day rule management. 
  • Change your cannula and insulin. 
  • Add an increased temporary basal rate onto your settings as you would usually do. 
  • Restart auto mode once ketones have resolved and it has been at least two hours since last pen injection (Remember the algorithm will not know that pen insulin has been given). 

Complex Meals   

For meals which normally cause a late glucose rise then the pump algorithm will usually deal with this. 

For low GI/high fat, high protein meals where a pattern of low glucose levels after eating is followed by delayed higher glucose levels then you will need to reduce the bolus given upfront. If you have been on a pump before and used split /extended boluses which worked then continue to split the bolus as before. Give the upfront portion as a bolus and let the pump algorithm cover the rest.

Date of Publication:02/10/2023
Reference Number:PIL215
Review Date:01/10/2026