How should I treat a child or young person with type 1 diabetes who has a blood glucose below 3.9 mmol/L, including if they use a hybrid closed loop system according to ACDC?

Assuming the child/young person is conscious and able to swallow, the practical ACDC approach is:

If blood glucose is <3.9 mmol/L

• This is an alert level for hypoglycaemia.
• Give fast-acting oral carbohydrate immediately.
• ACDC suggests a smaller dose for insulin pump / hybrid closed loop (HCL) users: typically 5–10 g fast-acting carbohydrate, because the usual full treatment can cause rebound hyperglycaemia.
• Recheck blood glucose in 15 minutes and repeat treatment if it is still <3.9 mmol/L.
• Once blood glucose is back above 3.9 mmol/L, give longer-acting carbohydrate if needed to maintain it, unless they are about to eat. [1]

If they are using a hybrid closed loop system

• Treat with smaller oral carbohydrate doses (5–10 g) rather than the standard larger hypo dose.
• The reason is that HCL systems may already be reducing insulin delivery, so standard treatment can overshoot and trigger rebound hyperglycaemia.
• Recheck after 15 minutes and repeat small doses if still low.
• ACDC notes local policy may vary, so follow your unit’s HCL guidance where available. [1]

If the blood glucose is <3.0 mmol/L, or they have significant symptoms

• This is more urgent: treatment should be immediate, and they may need help from another person. [1]

If they are drowsy, unconscious, seizing, or cannot swallow

• Do not give anything orally.
• Use glucagon or IV glucose and seek urgent medical help. [2]

For comparison, NICE’s general paediatric hypoglycaemia guidance recommends 10–20 g oral fast-acting glucose for mild-to-moderate hypoglycaemia, with a 15-minute recheck, but the ACDC HCL guidance is more specific and advises smaller doses for pump/HCL users. [2]