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Diabetes at the RCH

Insulin pump malfunction

  • Insulin pump failure: What to do

    Note

    If ketones are present (0.6mmol/L or higher), refer to hyperglycaemia and ketone advice link

      Failure to deliver insulin could be due to:

    • Pump malfunction
    • Flat battery
    • Empty cartridge
    • Running out of pump supplies

      For pump malfunction contact the pump company.

    Customer service numbers

    Medtronic:1800 777 808

    AMSL Diabetes (Tandem T Slim): 1300 851 056

    YpsoMed: 1800 447 042

    You must revert to injected rapid acting insulin until pump delivery is recommenced.

    Injected insulin dose 

    • Divide your pump total daily dose (PTDD) by 6 (PTDD ÷ 6) and administer this dose as rapid acting (NovoRapid® or Humalog®) insulin every 4 hours.
    • Eat 30 grams of carbohydrate with each injection of rapid acting insulin.
    • If you are awaiting a replacement pump, consider changing to rapid acting insulin with meals and once daily long acting insulin (multiple daily injections). See the information below. 

    Be prepared - All families on pump therapy should ensure they have:

    • Upload your insulin pump weekly or ensure that the pump is set up to do automatic uploads  
    • Have rapid acting insulin pens - Novorapid® or Humalog® penfill cartridges or disposable pens
    • Pen needle tips
    • A prescription (in date) for long-acting insulin (i.e. glargine/Optisulin®)
    • A plan of how to calculate doses if you need to revert back to injections 

    Remember know your pump total daily dose (PTDD)! 

    If you pump malfunctions you will not be able to retrieve this information from the pump. It is important to;

    • For Tandem T:Slim upload your pump weekly and have a copy of the settings page including the page with your PTDD available so that you have all of the needed settings available 
    • For Ypso insulin pumps. Your upload will automatically be on Glooko, it is important you can access these settings. It is important to know your username and password for Glooko. 
    • For Medtronic pumps, your pump will upload automatically if you are linked to the app. Ensure you know your CareLink username and password. If you do not have your pump linked to the app, you need to manually upload it weekly with the USB and have a copy of the settings page including the page with your PTDD available so that you have all of the needed settings available 
    • Know how to access your online information – contact your pump company if you forget your login details, or have difficulty accessing the upload website (CareLink® or Glooko®) 

    Changing back to multiple daily injections while waiting for a replacement pump

    If your pump has malfunctioned or needs replacement e.g. due to cracked screen, you will need to give insulin injections until you have a new pump set up. 

    Key tips: 

    • The information below explains how to work out doses for both long acting (basal insulin e.g. glargine/Optisulin®) and rapid acting (bolus insulin e.g. NovoRapid® or Humalog®). 
    • A replacement pump can take a few days to arrive.   
    • Ideally, you should know your Pump Total Daily Dose (PTDD), however if you don't, you can assume it is the same as your body weight (e.g. weight 30 kg, assume PTDD = 30 units)
    • If you are using CGM and the reading is less than 4.0 mmol/L or 15 mmol/L or higher check your fingerprick blood glucose level (BGL). Remember to check for ketones if the glucose is 15 mmol/L or higher - see ketone treatment guidelines if ketones 1.0 or higher (as you are now on injections ketones need to be managed when 1.0 mmol/L or higher) 
    • What ever option you follow, you will need closer glucose monitoring including checking overnight. If you use continuous glucose monitoring (CGM) connected to your pump and you cannot access your CGM on a smart phone, remember to regularly check your BGLs 4 - 6 x per day. 
    • On injections, hypoglycaemia management requires both quick acting and slow acting carbohydrates to manage the low glucose level

    Basal insulin:

    1. Give 40% of your PTDD as glargine (e.g. if your PTDD is 50 units, 40% = 20 units glargine). 

    • Glargine works for 24 hours and should be given at the same time each day. 
    • When you restart your pump, consider starting the pump when glargine is no longer working in the body (24 hours from when you gave glargine). 
      Other options to re start the pump when glargine is still working in the body is to: 
      - Tandem - Exercise Activity Mode until glargine is not working in the body
      - Ypso - Use Ease off mode or re-start the pump when glargine is not working in your body anymore 
      - Medtronic - requires 48 hours in Manual Mode with the new pump until Automode can be re-started and use a temporary basal rate at 0% until glargine is not working in the body anymore (this ensure basal insulin isn't doubling up with your injected insulin in your body 

    Bolus insulin: 

    • You'll need to give NovoRapid insulin with your main meals. 
    • Option 1 below assumes you know your insulin pump settings, including carb ratio and sensitivity / correction factor. If you do not have access to these settings, follow Option 2

    Option 1 

    a. To work out your insulin for food based on your current carbohydrate ratios. 

    - Find your carbohydrate ratio in your pump settings  

    - Divide the amount of carbohydrate to be eaten by your carbohydrate ratio setting 

    Example: I am eating 60 grams of carbohydrate and my carb ratio setting is 10 grams

    60 ÷ 10 = 6 

    Give 6 units of rapid acting insulin before eating

    b. To work out your insulin for corrections based on your current insulin sensitivity/correction factors. (we will use correction factor for the remainder of this page. This may be called sensitivity factor in your insulin pump. It means the same) 

    We advise to only correct above target glucose levels before meals using your current glucose level. 

    If you are wanting to give a correction after meal time insulin, wait at least 3 hours after your meal time rapid acting injection and closely monitor your glucose levels following this dose e.g. by doing a fingerprick BGL 2 hours after this dose or by monitoring on your CGM

    You need to know your "target glucose" for corrections. We will use a target glucose of 6 mmol/L

    The correction factor is an estimation of how many mmol/L 1 unit of insulin will lower your glucose

    Calculating your rapid acting insulin for correction: 

    There are a few ways to know how much insulin you need to help your glucose levels come down to the target range. The amount of insulin to give is based on what we call a correction factor (also called insulin sensitivity factor).

    We describe it as: 1 unit of insulin will lower your glucose by ‘X’ number of mmol/L, where ‘X’ is the correction factor.

    Step 1: Take your PTDD

    Step 2: Calculate your correction factor = 120 ÷ your PTDD OR take your current correction factor from your pump upload 

    Step 3: Work out the correction dose (the amount of extra insulin needed to bring your glucose level back into range). This amount will vary, depending on your current glucose level and your correction factor. 

    • Go to this calculator to work out how much need to correct. If you do not have a carb ratio just keep this blank and fill in your Correction/ISF and Current BG and it will do the calculation for you.
    • To do this calculation manually go through the following: 

    This is how you work out how much insulin you need at this time:  

    A. Calculate the correction gap to be treated: Current blood glucose level - Target glucose level (use 6 mmol/L) =

    B. Calculate your insulin correction amount by dividing your correction amount (worked out in A) by your correction factor (Worked out in Step 2 above)

    Correction amount ÷ correction factor = correction dose to be given

    C. Add the ‘correction dose’ amount to your usual mealtime insulin dose (i.e. the dose that will cover food).

    Example of working out the insulin you need for a correction: 

    My current glucose is 13.8 mmol/L before lunch. I am targetting my glucose to come down to 6 mmol/L. In my pump my current correction factor is 5.5 mmol/L/ 

    A. 18.8 (my current glucose level) - 6 mmol/L = 7.8 mmol/L is the gap my glucose level needs to come down to target 

    B. 7.8 mmol/L ÷ 5.5 mmol/L (current correction factor) = 1.4 units of rapid acting insulin

    If you have a half unit rapid acting pen you would round this dose to 1.5 additional units of rapid acting insulin but if you don't you would add an additiona 1 unit of rapid acting insulin to your lunch time dose.  

    Then, calculating your bolus dose for food and corrections: from the example above, 6 units of rapid acting insulin will be given for the 60 grams of carbohydrate and 1.5 or 1 units for the correction = 7 or 7.5 units 

    Option 2

    Working out your bolus insulin if you do not know your pump bolus settings

    Give 20% of your PTDD as rapid acting insulin with breakfast, lunch and dinner - i.e. 3 meals will give 60% of daily insulin as bolus insulin and 40% as basal (glargine/Optisulin®) insulin.

    e.g. if the PTDD is 50 units, 20% of 50 units = 10 units. Give 10 units rapid acting insulin (Novorapid® orHumalog®) with meals and 20 units glargine once daily  

    You may need to adjust this dose by 10-20% e.g. 1-2 units if you are eating more or less carbohydrate than usual. Generally aim for a minimum of 30 grams of carbohydrate to be eaten with each meal.

    You may need to adjust the long acting dose by 10% each day if you are having higher or lower glucose readings overnight or on waking

    Dose adjustment guide for injections


    Page updated September 2024