How to use Dexcom CGM Trend Arrows for Insulin Adjustments

Table of Contents

When you use a CGM (steady glucose monitor), you already understand how a lot of a game-changer this know-how might be in managing diabetes.

Gaining perception into the historical past of your blood sugar ranges, the place they’re now, and the place they’re heading sooner or later provides you with peace of thoughts and make managing your diabetes a lot simpler. safer.

However even should you like CGM, do you utilize development arrows to regulate your insulin? When you do not, you are lacking out on the know-how’s full potential.

Taking note of the CGM development arrows will enable you make extra proactive and knowledgeable selections when adjusting your insulin dosage.

The data on this put up is particular to Dexcom CGM techniques. Different CGM techniques additionally use development arrows, however they could have completely different meanings, so watch out when utilizing different techniques.

While you open the Dexcom app or have a look at your receiver, you will see your present blood sugar stage and your 30-minute blood sugar stage.

Its signal will seem within the type of an arrow. On the receiver, the arrow is to the suitable of your present blood sugar stage. Within the app, your blood sugar stage is displayed as a circle with an arrow round it.

You in all probability know that an arrow pointing up signifies that your blood sugar is rising and an arrow pointing down signifies that your blood sugar is falling, however are you aware how a lot and issue blood sugar into your insulin regulation?

Let’s begin with what the arrow signifies, in response to the producer.

development arrow	which means
two arrows straight up	BG can improve by greater than 90 mg/dL (5 mmol/L) in half-hour.
one arrow straight up	BG can improve as much as 90 mg/dL (5 mmol/L) in half-hour.
1 Arrow barely up	BG can improve by 30-60 mg/dL (1.7-3.3 mmol/L) in half-hour.
1 arrow subsequent to	BG doesn’t improve or lower by greater than 1 mg/dL (0.05 mmol/L) per minute.
1 Arrow down somewhat	BG can lower by 30-60 mg/dL (1.7-3.3 mmol/L) in half-hour.
One arrow pointing straight down	BG decreased as much as 90 mg/dL (5 mmol/L) in half-hour.
two arrows straight down	BG might lower by greater than 90 mg/dL (5 mmol/L) in half-hour.

sauce: Dexcom G6 Information

actual instance

As an example my blood sugar stage is 120 mg/dL (6.7 mmol/l) and my Dexcom exhibits two arrows straight above me.

On this case, you possibly can anticipate your blood sugar stage to doubtlessly rise above 210 mg/dL (120 + 90) inside the subsequent half-hour.

I attempt to hold it beneath 200 mg/dL, so I will probably give myself a correction bolus based mostly on this information (until I simply ate a meal or I am already taking sufficient energetic insulin that it hasn’t kicked in but).

CGM arrows might be very useful in managing blood sugar ranges, however provided that you know the way to reply to them.

A number of medical professionals have devised an method to securely and successfully help sufferers in administering insulin utilizing CGM arrows. Most significantly, all agree that the speed of rise or fall ought to be thought of when adjusting insulin doses. However what they disagree on is how insulin doses ought to be adjusted based mostly on these arrows.

The Endocrine Society reviewed 4 printed approaches in 2017 and created its personal tips. Their tips are Endocrine Society Journal Carried out in December 2017 (please word that the rules described listed here are for adults solely).

I take into account the Endocrine Society to be the final word authority on some of these suggestions, so I wish to share them with you.

Though this guideline was written for the Dexcom G5, no adjustments have been made to the brand new system’s arrows and the suggestions must also be legitimate for the Dexcom G6.

The Endocrine Society recommends adjusting insulin based mostly in your blood sugar stage half-hour later, quite than your present blood sugar stage. Nevertheless, as an alternative of calculating future blood glucose ranges after half-hour, we advocate adjusting the correction issue (CF).

This correction have to be made along with corrections for present blood sugar ranges and carbohydrate consumption.

CF signifies how a lot one unit of fast-acting insulin (corresponding to Humalog or Novolog) lowers blood sugar ranges. If you’re utilizing a pump, you possibly can test the CF within the settings. When you handle your diabetes with injections and do not know your CF, your well being care group may also help you calculate it.

Endocrine Society Advice Modifications Based mostly on Dexcom Development Arrows

arrow is displayed	Correction issue (CF)	Corrected dose (IU)
two arrows straight up	<25 25-50 50-75 >75	+4.5 +3.5 +2.5 +1.5
one arrow straight up	<25 25-50 50-75 >75	+3.5 +2.5 +1.5 +1
1 Arrow barely up	<25 25-50 50-75 >75	+2.5 +1.5 +1 +0.5
one arrow subsequent to	<25 25-50 50-75 >75	No adjustment No adjustment No adjustment No adjustment
1 Arrow down somewhat	<25 25-50 50-75 >75	-2.5 -1.5 -1- 0.5
One arrow pointing straight down	<25 25-50 50-75 >75	-3.5 -2.5 -1.5 -1
two arrows straight down	<25 25-50 50-75 >75	-4.5 -3.5 -2.5 -1.5

sauce: https://tutorial.oup.com/jes/article/1/12/1445/4642923

Let’s summarize with an instance.

You simply rolled away from bed within the morning, your urge for food hasn’t gone away all evening, and also you’re about to take a seat all the way down to a 20-gram carbohydrate meal. My blood sugar stage is 120 mg/dL (6.8 mmol/l) with two up arrows. Because of this it’s good to make three calculations:

First, it’s good to calculate your carbohydrate consumption. Assuming my insulin-to-carbohydrate ratio (ICR) is 10, I would wish 2 IU of insulin to cowl 20 grams of carbohydrates.
Subsequent, it’s good to calculate a correction dose based mostly in your present blood sugar ranges. If my CF is 25 and my blood sugar goal is 95 mg/dl (5.3 mmol/l), the correction dose is 1 IU (120-95 = 25 and 25/25 = 1 IU).
Thirdly, it’s good to calculate the correction based mostly on the arrow. There are two arrows pointing upwards and the CF is 25 as really useful, so 3.5 IU of correction is required.

Including all this up, my complete dose is 2 IU + 1 IU + 3.5 IU = 6.5 IU.

If my blood sugar had been decrease than my goal, or if I had seen a downward arrow, the really useful dose would have been decrease.

Let us take a look at one other instance to see if it is sensible.

I am getting away from bed once more, about to take a seat all the way down to a 20 gram carbohydrate meal, and my blood sugar is 120 mg/dL (6.8 mmol/l) and the arrow is pointing straight down.

The one factor that has modified in comparison with the final instance is the route of the arrow, which adjustments calculation #3.

Now there’s one arrow straight down and the CF is 25, so in response to the suggestions -2.5 IU correction is required.

Including all this up, my new complete dose is 2 IU + 1 IU – 2.5 IU = 0.5 IU.

Hmm, that is fairly a calculation. See the following part to learn to simplify it.

The endocrine suggestions make excellent sense to me, however require numerous calculations. Additionally, you aren’t allowed to take lower than 0.5 IU in corrections (which generally is a drawback in case you are very insulin delicate).

I choose to make use of a bolus calculator quite than doing all of the calculations each time I have to inject a bolus for a meal or correction dose. When you’ve got a pump, there is a good probability it has a built-in bolus calculator. When you’re on a number of every day injections (MDI) like I’m, you will have to look elsewhere.

Beforehand, I used an app known as RapidCalc for these calculations. I at the moment use an InPen, which is a SmartPen that sends information on to my telephone through Bluetooth, and has an related app to calculate dose and observe IOB.

The InPen app and RapidCalc mainly work the identical approach as bolus calculators, besides they really show the dosage (Please word that the RapidCalc app isn’t FDA authorized.).

After getting accomplished the essential calculations within the bolus calculator, you possibly can manually add development arrow corrections based mostly in your CF.

Keep in mind to react based mostly on what you’ll do over the following 1-4 hours, not what you might be doing if you end up about to manage the bolus.

When to not use CGM development arrows

All publications recommending using Development Arrow for insulin adjustment state that Development Arrow ought to by no means be utilized in some conditions, or no less than strict precautions ought to be taken.

When you plan to start out adjusting insulin doses utilizing development arrows, please learn these notes first.

4 hour meal window

The Endocrine Society recommends not utilizing Development Arrow for 4 hours after a bolus meal. As a substitute, we advocate the next:

2 hours after meals – Don’t appropriate hyperglycemia to stop insulin buildup
One or two up arrows at blood sugar ranges 150-250 mg/dL (8.3-13.9 mmol/l) 2-4 hours after meals – Contemplate adjusting utilizing CF
One or two up arrows for blood glucose > 250 mg/dL (13.9 mmol/l) 2 to 4 hours after a meal – Fingertip test, check for ketones (if >300 mg/dL/16.7 mmol/l) and use injection to appropriate. When you nonetheless see two up arrows after an hour, repeat.
Two to 4 hours after a meal, blood sugar ranges are round 150 mg/dL (8.3 mmol/l) with one arrow pointing barely downward. – Please test once more in half-hour
Two to 4 hours after a meal, your blood sugar is close to 150 mg/dL (8.3 mmol/l) with one or two down arrows. – Please test once more in quarter-hour
Two to 4 hours after a meal, when blood sugar ranges are round 100 mg/dL (5.6 mmol/l), one arrow barely down or one arrow down. – Contemplate consuming 15 g of carbohydrates and recheck after 20 minutes. If >70 mg/dL (3.9 mmol/l) and down arrow, test along with your fingertips and take into account taking an extra 15 g of fast-acting carbohydrates.
2– 4 hours after a meal, blood sugar is close to 100 mg/dL (5.6 mmol/l) with two downward pointing arrows – Comply with instruction (f) above, however devour 30 g of carbohydrates.

Blood sugar ranges rise quickly

When you see two up arrows in your receiver or app earlier than a meal, it is a good suggestion to pre-bolus diligently and inject your insulin 15-20 minutes earlier than your meal.

blood sugar stage drops quickly

When you see a “2” in your receiver or app earlier than a meal, we advocate ready till you begin consuming earlier than injecting insulin, or in case your blood sugar is approaching 150 mg/dL (8.3 mmol/l), holding again and never injecting till your blood sugar stage has leveled off.

frail/aged

The Endocrine Society recommends much less aggressive insulin dose changes for frail or aged adults to restrict the chance of hypoglycemia.

An upward arrow recommends a 50% discount within the proposed adjustment (e.g., 1 IU to 0.5 IU), and a downward arrow recommends a 50% improve within the discount (e.g., 1 IU to 2 IU).

Sick day administration and medicine issues

Don’t use development arrows to regulate insulin, as sure drugs (each prescription and over-the-counter) can intervene with CGM readings. As a substitute of relying fully on the CGM, use a fingerstick to learn the CGM.

All the time use frequent sense earlier than taking

As with all device within the diabetes toolkit, we advocate that you don’t apply the suggestions blindly.

When you really feel like chances are you’ll be off the really useful dosage, it might rely on how properly your physique is aware of what to do.

Though the Dexcom G5 and G6 CGMs are authorized for administration by the FDA, they are often inaccurate, so all the time test your fingers earlier than making any vital dosage changes.