Pump basals & Saxmaniac's revelation

[twodoor2]

I'm currently trying to understand pump basals.

There was a post the other day by Saxmaniac indicating that if he gives two small shots, an hour apart, they bring down the blood sugar more than one shot with the same amount of insulin. I'm curious, but I'm thinking that's how the basals in the pump kind of work. If you give pump basals, for example, .2u/h, that's a drip of a .5units per quarter hour (that's what Medtronic told me). Is there some correlation to the pump basal working more effectively when it is given in four smaller doses each quarter hour, vs one big dose at the beginning of the hour.

Also, if you use a temp basal, do you have to worry about the effects of it after the temp period is over? Is there a duration of insulin action caused by using the tiny amounts for the pump basals?

I also read another post the other day that stated if you increase the pump temp basal by 150% for one hour, it will bring down a high effectively. It was a "pump trick." It doesn't sound like there is much to the duration of insulin action if that is the case. If I did that, I would worry about the residual effect of stacking for the high.

Maybe I'm reading too much into this:confused:, but I just wanted to know what everyone thought, or what their experience was.

[Kaylee's Mommy]

I'm not sure how the MM pump works exactly, but with Cozmo and Animas the basal would be divided into 3 min intervals . The MM divides its basal based on how many units per hour so if You are only giving .2 units it may only be given ON THE HOUR (or .1 each 1/2 hr). ( .6units/hr would be 0.1 (the lowest available) given every 10 mins according to diabetesnet.com )
.2 units perhour would be .05 units every 1/4 hr not .5

I would think a temp basal would be the same as any other basal and not take effect for 2-3 hrs. I prefer to do a bigger correction than normal than increase the basal.


.05 is the lowest basal setting the pump will do.. it give it every 10minutes.. when you are only give .05, it give it in the beginning of the hour.. I believe if its .10, it'll give it the first .05 in the first 10minutes of the hour, then the next ..05 at the beginning of the 1/2hr.. in the first 10minutes.. it breaks it into half hours, then into 10minutes.. I believe this is the way it works..

[hypercarmona]

When I was pregnant, my CDE recommended using a temp basal to bring down mild highs instead of correction boluses. Her reasoning behind it was that there isn't the crash-inducing "tail" with a temp basal (even a huge one) like there is with a correction bolus, and that it's safer to come down softly than have a crazy drop. (High blood sugar exposure was bad for the baby, but high/low rollercoaster BGs were worse.) At the end of the temp basal, the extra insulin stops and so does the effect. Of course, this is at the end of the affected time period, based on how long the temp basal was set and when a basal change usually affects you-I can usually start to see results of a temp basal within 20 minutes. I still do this a lot, especially if I have a high after a meal, where I know I'm still going to go down some, but not quite enough to be in range. I'll do a temp basal for an hour or so, and instead of dropping like a rock into range, I'll drift down.

[twodoor2]

When I was pregnant, my CDE recommended using a temp basal to bring down mild highs instead of correction boluses. Her reasoning behind it was that there isn't the crash-inducing "tail" with a temp basal (even a huge one) like there is with a correction bolus, and that it's safer to come down softly than have a crazy drop. (High blood sugar exposure was bad for the baby, but high/low rollercoaster BGs were worse.) At the end of the temp basal, the extra insulin stops and so does the effect. Of course, this is at the end of the affected time period, based on how long the temp basal was set and when a basal change usually affects you-I can usually start to see results of a temp basal within 20 minutes. I still do this a lot, especially if I have a high after a meal, where I know I'm still going to go down some, but not quite enough to be in range. I'll do a temp basal for an hour or so, and instead of dropping like a rock into range, I'll drift down.


That's very interesting, I didn't realize that there wasn't a "crash inducing tail" with the temp basal. I guess what I'm trying to get at is the difference between giving a correction in one fell swoop (like an injection) vs. giving it in sections over the span of a certain period of time. It may also be more effective at bringing down highs because the multiple doses may overlap each other and square off the peaks. I don't know for sure, but this seems very interesting to me. I'm typically scared to use a temp basal to bring down an after meal spike because I think it's synonymous with stacking (in particular if I gave a correction to begin with), so I would like to know if this is a safer way to deal with spikes.

[jules12]

I'm currently trying to understand pump basals.

Is there some correlation to the pump basal working more effectively when it is given in four smaller doses each quarter hour, vs one big dose at the beginning of the hour.


Not sure if the following goes along with your question but.....

I thought that one advantage of the pump giving the basal is that is mimmick's the pancreas in that it gives small doses every so often (for us, the top of the hour). It also helps in that you can use the temp basal to gently adjust numbers and prevent crashes or spikes - we do this a lot with sports by either setting a temp basal before or after the event.

I also found that when he had the stomache flu and had ketones, I could increase the basal with a temp. setting rather than bolus.

My son is very sensitive right now so sometimes adjusting the basal works better for us than say giving a .3 correction. The good thing about the temp basal is you can stop it at anytime.

[Nancy in VA]

I'm not sure I'm fully understanding the question.

But, when Emma is sick, we use the temp basal rate a lot. Instead of doing corrections every 3 hours or so, when we see she is sick and running high, we run 20-30% higher basals for 4-6 hours at a time. I do think its more effective than the corrections. We just check more frequently to make sure she doesn't go low - if so, we turn off the basal - something you can't do with a correction.

[Mary Lou]

Like others, we use the temp basal to bring down highs. It has been our experience, with both boys, that this is a gentler way to correct, and really helps out when the highs are very high. Usually the drop in BG is more gradual, and less likely to cause a "rebound" low (for lack of a better term at the tip of my tongue).

There is certainly an impact two hours out, and you do need to be aware of insulin sensitivies and insulin on board. I do not know if the pump accounts for the increase in its IOB calculation, but we do, so we can override future corrections if we feel they are too high.

hope that answered your questions.

[Abby-Dabby-Doo]

I'm currently trying to understand pump basals.

There was a post the other day by Saxmaniac indicating that if he gives two small shots, an hour apart, they bring down the blood sugar more than one shot with the same amount of insulin. I'm curious, but I'm thinking that's how the basals in the pump kind of work. If you give pump basals, for example, .2u/h, that's a drip of a .5units per quarter hour (that's what Medtronic told me). Is there some correlation to the pump basal working more effectively when it is given in four smaller doses each quarter hour, vs one big dose at the beginning of the hour.

Also, if you use a temp basal, do you have to worry about the effects of it after the temp period is over? Is there a duration of insulin action caused by using the tiny amounts for the pump basals?

I also read another post the other day that stated if you increase the pump temp basal by 150% for one hour, it will bring down a high effectively. It was a "pump trick." It doesn't sound like there is much to the duration of insulin action if that is the case. If I did that, I would worry about the residual effect of stacking for the high.

Maybe I'm reading too much into this:confused:, but I just wanted to know what everyone thought, or what their experience was.

I'm not sure I'm fully understanding the question.

I might not be understanding the question either?!
First off, MM has a patent on the way the insulin is delivered-
Take whatever the basal is and divide by .05 (that is amount the pump delivers the basal) after you get that number, divide by 60 (60 minutes in an hour). And that is how many minutes apart the basal is given.
.10 divide by .05 = 2 divide by 60= 30 minutes (every 30 minutes .05 is delivered)
.15 divide by .05 = 3 divide by 60= 20 minutes (every 20 minutes .05 is delivered)
.20 divide by .05 = 4 divide by 60= 15 minutes (every 15 minutes .05 is delivered)
.25 divide by .05 = 5 divide by 60= 12 minutes (every 12 minutes .05 is delivered)
.30 divide by .05 = 6 divide by 60= 10 minutes (every 10 minutes .05 is delivered)
And so on and so forth.

The pump will not take basal into consideration for IOB.

***If your basal is .05 and you set a temp basal for 150% for one hour. She is still just getting .05. The pump increases it's doses by .05. 150% of .05 is .07, and it won't deliver that, so she's still only getting .05.

If your talking about a meal high- that is where the dual or square wave bolus will help take care of what the food is doing.

[Momof4gr8kids]

Temp basals are good for highs if
a) your corrections are keeping your child in the same higher range instead of bringing them down. Like you are keeping up with the bg rise.
b) Larger highs that need more insulin.

Julia's ISF is set to handle the lower highs because she needs less. I'd say she needs an extra 10% for bg over 200, and at least an extra 20% but probably closer to 30% for 300s. 400s she needs at least 50% and once we surpass that it usually means a ton of insulin and there is a major problem like illness.

Now, lets talk about bolus size. When you inject, or bolus insulin, either way you do it it can pool. Lesser amounts seem to absorb better.
Take a syringe and draw up your child's largest bolus that they have ever had. Then push out half a unit onto a plate, into your hand, you can use a cup, or a bowl, but I want you to see the insulin pool. Push out another half unit so that you have a full unit. Play with this so you see the different amounts until you have the all of the insulin out of the syringe. You'll see the difference, and I think you'll understand why. now back to the pool of insulin under the skin. We know that larger amounts of insulin have a bigger tail and last longer. How much insulin it takes to do that seems to be a person by person issue. Understanding that pool is there makes me wonder if it is the chicken or the egg, or both if you catch my meaning. Like is the insulin pooled under the skin the cause of the insulin lasting longer, and having the harsher tail, or is there something more to it?

Some people say bringing a high down slower is less traumatic on the body. I know for the person with D it sure feels a lot better to have a smoother transition.... but we as parents kind of freak out at the bigger numbers.

Marsha, I could go on and on about all of this with you. What I would suggest is try using your combo bolus for larger boluses and see if it works better. It should be the same as giving a bolus over time with your basal insulin. We usually pre bolus by 15-30 min using a combo bolus and it works really well for Julia.

[saxmaniac]

I would think basals and boluses are quite different. Splitting a 4u bolus into 2x2u is different than a basal meted out .05 units at a time. That's a huge difference. I also suspect the basal amounts are small enough that they're under some sort of threshold where absorption makes difference.

Additionally, if you're pumping, a second bolus goes into the same exact place as the first bolus. Two boluses on MDI would be like 2 different sites - so when pumpers say they can bolus twice with no difficulty, I believe it... but I think MDI might act differently.

Walsh says larger boluses take longer to absorb, and it follows that smaller ones absorb faster, but he doesn't say why. Perhaps it's is the surface area of the insulin pool, where it touches the body. A large bolus has a bigger pool, and touches the body proportionally less. (The volume of a sphere grows faster than the surface area does.) Anyway, that's my guess.

[Kaylee's Mommy]

I might not be understanding the question either?!
First off, MM has a patent on the way the insulin is delivered-
Take whatever the basal is and divide by .05 (that is amount the pump delivers the basal) after you get that number, divide by 60 (60 minutes in an hour). And that is how many minutes apart the basal is given.
.10 divide by .05 = 2 divide by 60= 30 minutes (every 30 minutes .05 is delivered)
.15 divide by .05 = 3 divide by 60= 20 minutes (every 20 minutes .05 is delivered)
.20 divide by .05 = 4 divide by 60= 15 minutes (every 15 minutes .05 is delivered)
.25 divide by .05 = 5 divide by 60= 12 minutes (every 12 minutes .05 is delivered)
.30 divide by .05 = 6 divide by 60= 10 minutes (every 10 minutes .05 is delivered)
And so on and so forth.

The pump will not take basal into consideration for IOB.

***If your basal is .05 and you set a temp basal for 150% for one hour. She is still just getting .05. The pump increases it's doses by .05. 150% of .05 is .07, and it won't deliver that, so she's still only getting .05.

If your talking about a meal high- that is where the dual or square wave bolus will help take care of what the food is doing.


thank you for posting that chart:) I knew they had a formula on it, but didn't know what was..but I have a question.. when the basal gets up into full units per hour, is it figured out the same way? I don't think it can be delivered any closer than every 10minutes.. is this correct? so, if you have a basal of say 3u an hour.. how would it deliever it? would it be .5 every 10 minutes?

[Abby-Dabby-Doo]

thank you for posting that chart:) I knew they had a formula on it, but didn't know what was..but I have a question.. when the basal gets up into full units per hour, is it figured out the same way? I don't think it can be delivered any closer than every 10minutes.. is this correct? so, if you have a basal of say 3u an hour.. how would it deliever it? would it be .5 every 10 minutes?

I have a call into my Pump Rep (the guy is great:)). I'll answer your question when I hear from him. Since Abby doesn't have those bigger basals I didn't think to ask. I wonder if it doesn't have something to do with which pump you have and the size of how much insulin it holds. It wouldn't hurt to know...

[Kaylee's Mommy]

I have a call into my Pump Rep (the guy is great:)). I'll answer your question when I hear from him. Since Abby doesn't have those bigger basals I didn't think to ask. I wonder if it doesn't have something to do with which pump you have and the size of how much insulin it holds. It wouldn't hurt to know...

Kaylee's not on these higher basals either, when you posted the chart it got me thinking.. I don't think it would have anything to do with the size of the pump (522/722) the only difference between the two is the resevoir size, everything else is the same, as far as I know.. I could be wrong:D

I know the smallest it can deliver at one time is the .05, and I THOUGHT it was every 10minutes (some pumps are every 3minutes..) but again, I could be wrong...:D

[twodoor2]

I would think basals and boluses are quite different. Splitting a 4u bolus into 2x2u is different than a basal meted out .05 units at a time. That's a huge difference. I also suspect the basal amounts are small enough that they're under some sort of threshold where absorption makes difference.

Additionally, if you're pumping, a second bolus goes into the same exact place as the first bolus. Two boluses on MDI would be like 2 different sites - so when pumpers say they can bolus twice with no difficulty, I believe it... but I think MDI might act differently.

Walsh says larger boluses take longer to absorb, and it follows that smaller ones absorb faster, but he doesn't say why. Perhaps it's is the surface area of the insulin pool, where it touches the body. A large bolus has a bigger pool, and touches the body proportionally less. (The volume of a sphere grows faster than the surface area does.) Anyway, that's my guess.


Thanks for everyone's insight on this. I suspect that the smaller the bolus, the flatter the peak, and if they are done in consecutive time spacings, they square off. I wish I could show you a picture of what I mean since I'm a more visual person, and I tend to communicate better through pictures. I'm guessing this is how the basal works since they're such small amounts. Kind of a flat curve, like Lantus, is what I'm picturing. I don't know though. I suspect the dose size and pool is proportional to the peak. Large dose, large pool, large peak. Small dose, small pool, small peak.

[Kaylee's Mommy]

Thanks for everyone's insight on this. I suspect that the smaller the bolus, the flatter the peak, and if they are done in consecutive time spacings, they square off. I wish I could show you a picture of what I mean since I'm a more visual person, and I tend to communicate better through pictures. I'm guessing this is how the basal works since they're such small amounts. Kind of a flat curve, like Lantus, is what I'm picturing. I don't know though. I suspect the dose size and pool is proportional to the peak. Large dose, large pool, large peak. Small dose, small pool, small peak.

I can tell you that when we started pre-bolusing Kaylee we saw a HUGE difference in the way she reacted to the carbs.. it could be either the way it was delievered, or the mear fact that I'm pre-bolusing.. for example, I pre-bolus her 15 carbs about 15 minutes before she began to eat, once I am sure of what she's going to eat I then do a dual wave with the rest of the carbs, say 30, with pretty much 50% up front and 50% over 3 hours.. so, she's getting two smaller boluses of 15carbs worth, or .75u for her, and then the other 15carbs over 3 hours.. her sensor will look like a rolling hill.. now, if I give it to her without the prebolus and give 45carbs in a dual wave with 50% up front, or 22.5carbs which equals to 1.125 (of course rounded down to 1.1u) and then another 1.1 u over the next 3 hours we get a mountain peak instead of the pretty little hill..

Now, if this because I prebolused so part of the insulin is working as the food is starting to absorb, OR is it because they are broken down into smaller doses and there for having more of an effect, I don't know.. I just know we get far better numbers with the pre-bolus followed by a dual wave set for at least 3 hours :cwds:

[twodoor2]

I would think basals and boluses are quite different. Splitting a 4u bolus into 2x2u is different than a basal meted out .05 units at a time. That's a huge difference. I also suspect the basal amounts are small enough that they're under some sort of threshold where absorption makes difference.

Additionally, if you're pumping, a second bolus goes into the same exact place as the first bolus. Two boluses on MDI would be like 2 different sites - so when pumpers say they can bolus twice with no difficulty, I believe it... but I think MDI might act differently.

Walsh says larger boluses take longer to absorb, and it follows that smaller ones absorb faster, but he doesn't say why. Perhaps it's is the surface area of the insulin pool, where it touches the body. A large bolus has a bigger pool, and touches the body proportionally less. (The volume of a sphere grows faster than the surface area does.) Anyway, that's my guess.

It turns out that Saxmaniac (Scott) was right about this. Please see the aformentioned article. It is the surface area.

Sorry Scott if I beat you to posting this. I was pretty excited that you figured it out. Thanks to Twinket for sending me the article!!

Anyways, the designers of syringes are working on a syringe to have tiny holes up and down the needle and this will help insulin work faster and more efficiently, all due to the "surface area" effect. This is also why pump basals are probably are more "potent" as well since they are released in proportionally spaced portions throughout the hour.

http://i19.photobucket.com/albums/b179/igglet/InsulinAbsorption.jpg

[saxmaniac]

Thanks so much for posting this. Since we started pumping I've had to get over my fear of bolusing and correcting more frequently. It's good to find this actually written down.

[Rachel]

What I would suggest is try using your combo bolus for larger boluses and see if it works better. It should be the same as giving a bolus over time with your basal insulin. We usually pre bolus by 15-30 min using a combo bolus and it works really well for Julia.

The nice thing about this strategy - if you are using it for corrections, rather than doing the temp basal - is that then the insulin is factored into the insulin on board.

[frizzyrazzy]

We have often used an extended bolus at night to bring down a high for just these reasons. Little amounts, more often work better than one large bolus.

[Jacob'sDad]

I read this topic yesterday morning and had a comment and then forgot about it. Anyway:

I like the idea of using a combo bolus instead of a temp basal to lower a high BG gradually.

If you use a temp basal you have to do an awful lot of calculations to get it right. You have to decide how much total insulin it will take to bring down the high. Then you have to calculate how much that is per hour for the temp basal. Then you have to calculate what that equals as a percentage increase. If your right at a point in the day where a new basal rate kicks in there's even more calculating. Or you can guess. I don't like to guess unless I have to.

If, however, you use a combo bolus you don't have to do ANY calculating as long as the correction factor is right. For example: Let's say you wanted to bring down a BG of 300 over 3 hours. With the Animas 2020 you simply put the BG of 300 into EZBG and then select combo bolus. Set it for 0% now and 100% over 3 hours. It will calculate how much the bolus should be. It will split up that bolus equally over a 3 hour period.
You may have to experiment with changing the correction factor because it may not lower BG the same as it would if you were giving the correction all at once.

With either method you have the ability to cancel either the temp basal or the combo once BG reaches a certain point. If you check BG and it is down to 140 you might want to cancel the temp basal or combo since the effects may continue for up to 2 more hours.

[twodoor2]

Question, is the regular basal still delivering at the same time as the combo bolus? If so, you're probably giving more insulin then needed. I don't use the combo bolus much, so I'm not sure.

[saxmaniac]

Thanks for the input here... the omnipod does the same thing. If you put in a BG it will suggest a correction, and you can extended just like a meal. Other than being able to cancel it, what are the benefits of an extended correction? How long is the best correction?

Yes, the basal still goes during the combo bolus. All you're doing it stretching bolus of X units over time.

[Jacob'sDad]

Question, is the regular basal still delivering at the same time as the combo bolus? If so, you're probably giving more insulin then needed. I don't use the combo bolus much, so I'm not sure.

Look at it this way: If I were to just do a regular correction for a high of, say, 300 with an ISF of 150 and a target of 125, the pump would tell me to give a correction of 1.15 units (I think?). With a combo bolus it would simply give that same 1.15 units but spread it out over whatever time frame I choose. If the concern is that less of a correction will be needed because it is spread out and absorption is better, then the ISF could be changed from 150 to a higher amount like 175. With the Animas pump you can change ISF on the fly.

[twodoor2]

Look at it this way: If I were to just do a regular correction for a high of, say, 300 with an ISF of 150 and a target of 125, the pump would tell me to give a correction of 1.15 units (I think?). With a combo bolus it would simply give that same 1.15 units but spread it out over whatever time frame I choose. If the concern is that less of a correction will be needed because it is spread out and absorption is better, then the ISF could be changed from 150 to a higher amount like 175. With the Animas pump you can change ISF on the fly.

Yes, I understand that, but when you do a temp basal it takes the place of the regular basal. I'm not sure what you're doing is taking the place of the regular basal, but adding additional insulin on top of it. That's where I'm unsure.

[saxmaniac]

but when you do a temp basal it takes the place of the regular basal. I'm not sure what you're doing is taking the place of the regular basal, but adding additional insulin on top of it. That's where I'm unsure.

You asked about a combo bolus, a different thing than a temp basal. Or am I confused here??

[twodoor2]

You asked about a combo bolus, a different thing than a temp basal. Or am I confused here??

"Jacob's Dad" (Dave) was mentioning that he rather use a 0%/100% combo bolus to correct since it will calculate how much you need to give each hour. He rather do this than a temp basal since you have to do the calculations yourself. My thing is that a temp basal is different from a combo bolus in the fact that the temp basal replaces the regular basal for a specific period of time. I believe, but I'm not sure so I'm hoping someone will enlighten me, is that a combo bolus does not replace the existing basal, but adds additional insulin on top of what the regular basal is already giving out. Or maybe I'm just not understanding anything?:confused:

If someone could correct/enlighten/notify me on how the combo and temp basal work in conjunction with the regular basal, that would help.

Thanks!

[Jacob'sDad]

Yes, I understand that, but when you do a temp basal it takes the place of the regular basal. I'm not sure what you're doing is taking the place of the regular basal, but adding additional insulin on top of it. That's where I'm unsure.

It IS added on top of the regular basal rate, but if want Jacob to have 1.15 extra units to bring down a high, I DO want it added on top of the regular basal. Actually, it has nothing to do with the basal rate. The basal goes on as always, but every so many minutes the portion of the correction bolus is given too. I doubt if they occur at the same time.

To me basal rate is just BASAL RATE. It is background insulin that is meant to keep BG steady. I don't think it should be manipulated to correct temporary highs. That should be done with a correction bolus, and if it is desired to give that correction over time, it can be done with an extended (combo) bolus.

[Twinklet]

A combo bolus adds additional insulin on top of the basal rate.

A temp rate replaces the basal. The only disadvantage of a temp rate is that it is not accounted into IOB.

If Jacob's Dad is using a combo to make a correction, he'd have to enter it as a meal bolus in order to get to the combo screen, wouldn't he? Then he'd have to figure it out manually.

[saxmaniac]

The combo bolus does not affect the basal at all. When I do a TDD report, which is broken into basal and bolus, the basal component is unchanged. If the combo bolus replaced it, I would (hope to) see less in the delivered basal report.

I suppose you could use a temp basal to emulate a combo bolus, but man, that looks like a lot of work, for no gain I can see.

[Twinklet]

We've used a temp basal to imitate a combo bolus when we already have a combo running. We do have to figure it manually and remember that her IOB will be incorrect, but it can work if you need it to. When Emily has pizza, I have to run an 8-hour-long combo, so if she wants something else combo'd after that we have to do the temp rate/"manual combo".

[twodoor2]

Thanks for the explanations!:D