Hi
@andyfrith, What you are experiencing jibes with me. I find if I happen to have a BSL >12 that I need to up the correction dose and even the basal dose. The reason is given as the BSL rises the insulin resistance increases (or insulin sensitivity decreases). Also trying to do exercise with high BSLs can just drive them higher.
The tricky bit is by how much to increase the correction doses.. As a diabetic for 52 years, 7 on a pump, not as professional advice or opinion: For me, and this may or may not apply to you so please check with your DSN/doctor:
if it appears to be a one off high from perhaps too much to eat etc I add a 20% increase to my correction dose if BSL is 12 to 15mmol/l plus up my basal dose by 10 to 20% for the next 2 to 3 hours. And I check my BSL at the 2 hours mark (I am on Novorapid). And I find it is better to get the BSL down stepwise. Doing a big hit of bolus risks a hypo later with BSL then going up and down like a yo-yo!!
if my BSL > 15 mmol/l I also check for ketones (I have a meter and strips that will check for ketones): I ring my DSN and discuss with her what to do: with no ketones present I will discuss whether to just add the 20% as above and see what happens but if ketones are present the decision is often to use a small dose of Novorapid intramuscularly to bring the BSL done more quickly plus keep the basal dose increased for longer in case I am in the early stages of an infection of some sort.
There are occasions when I know my BSL is going to be out of whack such as after a flu injection. Apparently the challenge of the vaccination to my immune system is still a stress to my body the way a cold virus etc is, some I have a routine for this which is, as soon as the BSLs start to rise (usually on the day after the vaccination) I increase my bolus and basal doses by 20 to 30 % and stay with that provided my bsls stay below 12 mol/l and continue like this for about 4 days.
Best of luck with those correction doses.
And never be afraid to ask for help from your DSN/doctor.!!!