# Dual wave to cut spike immediately after eating?



## Pigeon (Jan 18, 2022)

Hi there, I'm interested in hearing other pump users' ideas regarding a conversation I had with my consultant today. I'm pregnant with baby no 2 so lots of attention to my Libre graphs and "what happened there?" kind of questions. I use a Medtronic 780g with Novorapid. HBA1c is 51, so not bad, but he was looking at post-prandial spikes. I tend to find lunch most problematic - normally a flatbread sandwich, yoghurt, apple and satsuma, around 45g carbs. It's easy to pack up for a work lunch or a quick one at home.

Lunchtime yesterday I took the bolus around 30 mins beforehand (11.30) (11g/u). Ate a few peanuts at the start of the meal to try to slow down absorption, went for a 10 min brisk walk immediately afterwards. Spiked to 14, came back within range by 2.30. He said I should  reduce the reduce the carb/insulin ratio... I argued no as I was back within range within 3 hours. So then he said I should dual wave 50:50 over 1 hour delivery as giving 5 u or so at once was too much and would cause a "puddle" of insulin which was slower to absorb than giving the dose over an hour. Has anyone heard this theory before? When I google dual waves or look it up in the books I have it only mentions dual waves/extended bolus for fatty/slow to absorb foods such as pizza, pasta, roast dinner, rice, which is what I use it for at present. Or if I'm worried about hypo-ing while eating (e.g. due to exercise) I might do a dual wave to avoid that. I spoke to the DSN on the phone last week who was also surprised I'm not dual waving for every meal, so just wondered if I have missed something somewhere or if they're just quoting something they've read which doesn't apply to real life?

My normal technique (better suited to work days) is to keep my fruit for mid-afternoon but bolus for it before lunch so that I eat it when I am coming back in range, with some active insulin still on board. I mentioned this today and he dismissed it as a technique for countering highs. It worked for me in my last pregnancy so I think I just need to remember to do this now even when I'm at home (I've gone part time since baby #1) and not forget to eat the fruit later on!

I suppose the obvious thing to to try it and see then go back to my method if it doesn't work, I was just interested if anyone has heard his "puddle" theory before, or uses dual wave for all meals?


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## Inka (Jan 18, 2022)

Congratulations on your pregnancy @Pigeon  I was never told to use a dual-wave when pregnant. How many weeks are you? I did find I had to change my ratios and also pre-bolus noticeably earlier as time went on.

If what you did worked last time, you could do that again. What I did was bolus enough to be below  7.8 at one hour. This meant I often dropped a little a bit later, but I just ate a small carb snack. That worked very well for me and kept my numbers good. Your fruit idea sounds similar, I think?


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## Pigeon (Jan 18, 2022)

Thank you for your reply, Inka, I'm 12 weeks. 
 The past few weeks have been full of hypos but hopefully I'm on top of that now, until insulin requirements start going up again!


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## SB2015 (Jan 19, 2022)

Congratulations @Pigeon 

I have used dual waves but only for fatty meals in order to deal with the slow release of glucose.  You sound like you have a good strategy with the combination of pre bolusing, exercising and delaying the faster acting carbs.  

I have not had to deal with diabetes and pregnancy so this suggestion may not be relevant to you.  When I was trying to lower my spikes, having seen what was happening by using the Libre,  I set a lower target for my meals and this leads to less glucose, so although I would go up after a meal it was smaller.  All the other things I would  try you are already doing.

I have not heard of the issues around pooling on boluses.  I like the slower delivery rate that is available in the 780 and found that that helped with any issues around skanky cannula sites.  

Let us know how you get on.


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## Pigeon (Jan 19, 2022)

SB2015 said:


> , I set a lower target for my meals and this leads to less glucose, so although I would go up after a meal it was smaller.


Thanks for your reply. Sorry I don't quite understand what you mean by the above, do you mean the target on your pump or Libre? And how does this lead to less Glucose- you eat less? Or do you mean you start off with lower BG so the rise takes you less high?


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## trophywench (Jan 19, 2022)

Glad @Pigeon asked that, I wonder what you meant, too.

Any insulin can 'pool' and absorb less quickly and though it normally happens with basal esp. eg Lantus and that is usually a higher dose in one go as opposed to bolus insulin, there's nowt to stop it occurring with 'fast acting' insulin cos it's going into the same skin.

Just that not everyone always gets pooling/poor absorption so it's one of those things that tends to get overlooked (like the effect of viruses and T1) .... think it's probably happened recently at your hospital though (or eg some authority like Partha Kar has just published an article/given a speech about it) so they have a current bee in their bonnet about it.  What you've said about your previous strategy with the fruit sounds sensible to me - but also the extended bolus sounds reasonable - so I'd suggest trying the extended bolus to begin with a see what happens but if not enough, try remembering to eat the fruit later and see if that works, I'd think with a combination of the two you'll get there!

Or - just do one of em, because you know very well it'll all get harder in the last trimester you could keep whichever one you didn't do now, up your sleeve to whip out then!


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## SB2015 (Jan 19, 2022)

Pigeon said:


> Thanks for your reply. Sorry I don't quite understand what you mean by the above, do you mean the target on your pump or Libre? And how does this lead to less Glucose- you eat less? Or do you mean you start off with lower BG so the rise takes you less high?


Sorry not to have explained more clearly.

I set a lower number of carbs that we would aim to eat at each meal.  We now aim for the carbs in our meals to be about half what they were before, and with fewer carbs, that is less glucose in the system, so a smaller spike.  This is still not ‘low carb’ just what we are happy with.

With effective timing of the bolus I can usually get breakfast to be a small bump in glucose levels, as that is the most consistent meal of my day.  Lunches are more difficult as I don’t always have time to pre bolus.

I hope that that makes more sense.


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## Pigeon (Jan 19, 2022)

Thanks for clarifying, SB! I used to eat very carby meals til I first tried a cgm and saw the big spikes, so my flatbread etc is actually my lower carb solution, rather than a roll or similar. It's hard to think how I can go any lower carb without cooking separately. 

Well I tried the dual wave today and I've currently got a spike of 17 so I think I'll stick to my way of doing things! Thanks all for the reassurance!


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## Pumper_Sue (Jan 19, 2022)

Pigeon said:


> Well I tried the dual wave today and I've currently got a spike of 17 so I think I'll stick to my way of doing things! Thanks all for the reassurance!


You don't have to do a 50/50 split you can perhaps do a 80/20 over two hours. I use Fiasp and always split my dose 80/20 over a two hour period.
The split though is trial and error for everyone


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## Inka (Jan 20, 2022)

I can’t see the logic of a dual wave. You need to get all the insulin in to stop the spike as pregnancy targets are super-strict. You then top-up with a small amount of carbs at 3 or whatever hours. That way your blood sugar stays in target. I found I needed a fair whack of insulin due to pregnancy.

I’ve heard of the puddle effect but I’ve never heard of that for 5 units. 15 yes, I can see that, but 5 units isn’t a big dose. If what you’re doing is working, then I’d carry on and continue to monitor how it works.


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## Pumper_Sue (Jan 20, 2022)

If it were me I would be redoing my basal test and taking things from there. Something isn't right to spike like that.


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## Pigeon (Jan 20, 2022)

Thanks @Pumper_Sue , useful advice as ever. My understanding was that dual waves are often used with FIASP to prevent hypos during a meal, which does make sense, but that's not the problem I'm having. 

I was a bit disillusioned last night with the spike I got, but thinking about it, I had also taken the pump off for swimming 3- 4.30 and replaced the cannula before tea - I think maybe it was a dodgy cannula site as I got a big breakfast spike this morning (when I don't normally) so I have now swapped it again. So probably not a good meal to throw experimentation with bolus into the mix! 

Will attempt a basal test this evening to check the background rate.


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## rebrascora (Jan 20, 2022)

I have no experience of pregnancy, so take my input with a pinch of salt, but I too can't see the logic of delaying some of the insulin with a dual wave when you are clearly needing all the insulin there ASAP to tackle that spike. To me increasing the prebolus time would make more sense to give the NR more time to get going. When I was using NR I had to give myself 75mins prebolus time at breakfast to prevent spiking to mid teens each day and then swooping back down into range which really wasn't pleasant. I am now using Fiasp but still need 45mins prebolus time at breakfast with that and I tend to get my food ready and then scan with Libre to watch for my levels starting to come down and not eat until I am in the 5s or maybe low 6s. I am not saying this will work for you but it might be worth experiementing with your prebolus time a little further at lunchtime. I would add that my lunchtime and evening prebolus time is usually just 20 mins and if levels are low 5s or 4s I can usually get away with eating more or less straight away, but in the morning my insulin has to work hard against a strong Foot on the Floor response and as a result it takes much longer to work but my body is very fast at digesting carbs, even slow release carbs. 
Anyway, what I am suggesting is to try giving yourself another few mins prebolus time each day beyond the 30 to see if that improves things and hopefully find the optimum balance time for your insulin and food and maybe consider setting a level, above which you delay eating.....So at breakfast time I don't start eating until levels drop below 6.5. If they are already below 6.5 then I watch for the Libre arrow showing that the insulin is starting to kick in before I eat. I appreciate that is not possible every day but I have found that once I get into a routine with it, it works pretty well for me to prevent spikes.

It might also be worth discussing a possible change to a faster acting insulin like Fiasp with your team, particularly if pregnancy is causing a lot of insulin resistance.


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## Pigeon (Jan 20, 2022)

Ooh, 75 mins is interesting, @rebrascora ! I feel a bit daring waiting 30 mins, and again, at past appointments dsns have been surprised that I still got a spike with this and suggested I was "missing the peak" - which again makes no sense if the bg level comes down eventually. Just goes to show many of them have no idea of what life is like outside of a textbook! I'll give your idea of increasing by 5 mins each day a try. Thanks!


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## Inka (Jan 20, 2022)

In later pregnancy, I had to pre-bolus 50 mins or up to an hour in advance for breakfast @Pigeon So weird to feel the insulin resistance! 

Another thought - is your bolus ratio ok? Mine changed a lot during pregnancy and I found even when my basal was ok, I sometimes needed to change my ratio for one or more meals. This happened more in the second half of pregnancy but in the first half things could change then change back again, so it’s something to consider.


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## rebrascora (Jan 20, 2022)

Pigeon said:


> Ooh, 75 mins is interesting, @rebrascora ! I feel a bit daring waiting 30 mins, and again, at past appointments dsns have been surprised that I still got a spike with this and suggested I was "missing the peak" - which again makes no sense if the bg level comes down eventually. Just goes to show many of them have no idea of what life is like outside of a textbook! I'll give your idea of increasing by 5 mins each day a try. Thanks!


My consultant was absolutely horrified that I was pre-bolusing that far in advance but he couldn't argue with my results! The problem was that I would get distracted during that hour and a quarter and try to fit things into it that were OK if everything went smoothly but occasionally I got side tracked or delayed and ended up hypo. 
With Fiasp, 45mins is better to work with, as I can fit my morning routine into it. The key thing for me is that I make my breakfast first so that, when that Libre arrow starts to point downwards, it is ready to eat. 
It amazes me just how quickly my body breaks down food, even low GI like porridge can get from my mouth to my finger tip in 20 mins, but insulin takes the best part of an hour!.... It's a bit frustrating!


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## Pumper_Sue (Jan 20, 2022)

Pigeon said:


> Lunchtime yesterday I took the bolus around 30 mins beforehand (11.30) (11g/u). Ate a few peanuts at the start of the meal to try to slow down absorption, went for a 10 min brisk walk immediately afterwards. Spiked to 14, came back within range by 2.30.


I can not see how the carbs are absorbed so quickly to cause the hike in blood sugars like that and basically bolus doing sod all for you.
So my way of looking at it is check the basal and see what's going on. 99.9% of problems are basal


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## Pigeon (Jan 21, 2022)

Did a basal test today over my normal lunchtime and it was pretty flat. So the spike is definitely caused by carbs, seems like I have similar quick absorption to @rebrascora and @Inka . I've now had my lunch (2 hrs later than normal, full bolus 30 mins ahead) and the spike is happening now. 

So tomorrow I will try the dr/dsn dual wave idea (just so I can definitely say it didn't help) then try increasing the time of pre bolussing. 
 I could ask about FIASP (once I've shown them their suggestion didn't help), but I don't know if they will be reluctant for me to make a big change whilst pregnant? 

Thanks all for your suggestions


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## rebrascora (Jan 21, 2022)

Sounds like a good plan. Whilst their suggestion doesn't really make any sense to us, that doesn't mean to say we know everything and they are wrong, so you have to give it a go and there are always quirks with people's bodies and the way they respond to insulin or food which is different. I know I am different in needing so long for insulin to absorb, but I am not the only one. I imagine your pregnancy hormones will be having an impact with that on your body. What I do know is that a DSN or consultant would be extremely unlikely (or probably never) suggest anyone prebolus more than 30 mins in advance of food for fear of people hypoing..... and many people would....  but some people do need longer and to me that is why they should encourage us to cautiously experiment and find what works for us as individuals rather than sticking with "rules". 

I found the change over from NR to Fiasp quite frustrating and challenging as Fiasp has it's own quirks, and after 3 months the first time I tried it, I gave up and went back to NR but then decided to give it another attempt and made a pact with myself that I would stick it for a full 12 months before making a definite decision and again I had 3 months of frustration with it and then about 4-5 months in I started to be more aggressive with it (probably out of frustration and perhaps increased familiarity. I started using more insulin than I thought I should need, doing corrections when my levels were 8 or 9 as once they got into double figures the Fiasp just seemed to become so much less effective and even stacking corrections on occasion  and that has made a big difference to my management with it. I am certainly not recommending stacking insulin, but it is another "diabetes rule" that I break because it works for me. I am normally not a rebel at all so I find it quite odd that I seem to like to break the "diabetes rules" so frequently.

You might get away with Fiasp straight away, but I know of other people who have struggled with a change to Fiasp or at least found it "quirky", so if you can manage a work around with an extended prebolus of NR or whatever other strategy works, for this, hopefully limited period, it is probably better than swapping insulin at this stage.


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## Inka (Jan 21, 2022)

Pigeon said:


> Did a basal test today over my normal lunchtime and it was pretty flat. So the spike is definitely caused by carbs, seems like I have similar quick absorption to @rebrascora and @Inka . I've now had my lunch (2 hrs later than normal, full bolus 30 mins ahead) and the spike is happening now.
> 
> So tomorrow I will try the dr/dsn dual wave idea (just so I can definitely say it didn't help) then try increasing the time of pre bolussing.
> I could ask about FIASP (once I've shown them their suggestion didn't help), but I don't know if they will be reluctant for me to make a big change whilst pregnant?
> ...



You could up your ratio for lunch too maybe. As well as pre-bolusing, I found I needed increased ratios to help, especially later on. I thought my increases were big but another lady went from 1:10g to 1:1g in the third trimester - so 10 times as big a ratio.


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## everydayupsanddowns (Jan 21, 2022)

Doesn’t Dr B suggest in his ’law of small numbers’ that larger doses absorb less reliably.

And who was it that used to say 7u was a good rule of thumb for a max dose?

I have always been bemused by people saying they were using dual wave to reduce a spike - and this is the first time I’ve actually heard a suggestion of how delaying delivery might improve things.

5u does seem small though.

If you are interested, I guess you could 50:50 over 30 mins from your usual prebolus time?

Be interested to see how that worked for you.


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## Pattidevans (Jan 22, 2022)

everydayupsanddowns said:


> And who was it that used to say 7u was a good rule of thumb for a max dose?


Bernstein again!


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## everydayupsanddowns (Jan 23, 2022)

Pattidevans said:


> Bernstein again!



Ha! Probably the same article then. Never been too keen on what I’ve heard about his approaches, so that free article is the only thing I’ve read. Fortunately max of 7u or thereabouts is plenty for the vast majority of my meals


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