Find out how to use Dexcom CGM Pattern Arrows for Insulin Changes

Should you use a CGM (Steady Glucose Monitor), you most likely already understand how a lot of a game-changer this know-how will be in terms of managing your diabetes.

Having perception into our blood glucose historical past, the place what our blood sugar is correct now, and the place it’s headed brings peace of thoughts and makes managing diabetes quite a bit simpler and safer.

However even in the event you love your CGM, do you make the most of the development arrows for insulin changes? If not, you’re really lacking out on the complete potential of the know-how.

By listening to the CGM development arrows, you’ll be capable of make extra proactive and knowledgeable selections in terms of adjusting your insulin doses.

The knowledge on this put up is particular to the Dexcom CGM system. Different CGM programs use development arrows as nicely, however they could have completely different meanings so please watch out using the data right here in the event you use one other system.

What the Dexcom CGM development arrows inform us

If you open your Dexcom app or take a look at your receiver, you’ll see your present blood sugar in addition to a sign of what your blood sugar can be in half-hour.

That indication comes within the type of arrows. On the receiver, the arrows are to the fitting of your present blood sugar. Within the app, it’s proven as a circle along with your blood sugar and the arrows across the circle.

You most likely know that an up arrow signifies that your blood sugar is rising and a down arrow that it’s falling, however are you aware by how a lot and the right way to embody it in your insulin changes?

Let’s begin with what the arrows point out based on the producer:

Supply: Dexcom G6 information

Actual-life instance

Let’s say my blood sugar is 120 mg/dL (6.7 mmol/l) and my Dexcom is displaying 2 arrows straight up.

On this case, I can count on my blood sugar to probably enhance to above 210 mg/dL (120 + 90) throughout the subsequent 30 min.

I attempt to keep beneath 200 mg/dL so I’d most definitely give myself a correction bolus primarily based on this information (so long as I didn’t simply eat a meal or have already got sufficient energetic insulin on board that simply hasn’t kicked in but).

Find out how to calculate your insulin changes primarily based on the Dexcom development arrows

Your CGMs arrows will be extremely useful for blood sugar administration — however provided that you know the way to reply to these arrows.

A number of medical professionals have provide you with approaches for utilizing CGM arrows to assist sufferers dose insulin safely and successfully. Most significantly, all of them agree that we should always take the rise or fall fee into consideration when adjusting our insulin doses. What they disagree on, nevertheless, is strictly how insulin doses must be adjusted primarily based on these arrows.

The Endocrine Society reviewed 4 revealed approaches in 2017 and got here up with their very own tips. Their tips had been revealed within the Journal of the Endocrine Society in December 2017 (please word that the rules mentioned listed below are for adults solely). 

Since I contemplate the Endocrine Society the best authority in terms of one of these advice, I’m going to share their advice with you.

Though the rules had been written for Dexcom G5, no modifications have been made to the arrows for the newer programs and the suggestions must be legitimate for Dexcom G6 as nicely.

The Endocrine Society recommends that you simply regulate your insulin primarily based on what your blood sugar can be in half-hour, quite than what it’s proper now. However as an alternative of calculating what your future blood sugar can be in half-hour, they suggest that you simply regulate your correction issue (CF).

This correction must be made on high of any correction on your present blood sugar in addition to any carbohydrates consumed.

Your CF is how a lot one unit of rapid-acting insulin (like Humalog or Novolog) will lower your blood sugar. Should you use a pump, you possibly can see your CF in your settings. Should you handle your diabetes with injections and don’t know your CF, you possibly can ask your medical staff that will help you calculate it.

Endocrine Society’s advisable correction primarily based on Dexcom development arrows

Supply: https://educational.oup.com/jes/article/1/12/1445/4642923

Let’s sum it up with an instance:

I’ve simply rolled off the bed within the morning, had no lows in a single day, and I’m about to sit down down for a meal of 20 grams of carbohydrates. My blood sugar is 120 mg/dL (6.8 mmol/l) with two arrows up. Which means I’ll should do three calculations:

1. First, I’ve to calculate the dose for my carbs. Assuming my Insulin to Carb Ratio (ICR) is 10, I’d want 2 IU of insulin to cowl my 20 grams of carbs.
2. Secondly, I’ll should calculate my correction dose primarily based on my present blood sugar. If my CF is 25 and my goal blood sugar is 95 mg/dl (5.3 mmol/l), my correction dose is 1 IU (120-95 = 25 and 25/25 = 1 IU).
3. Thirdly, I’d should calculate the correction primarily based on the arrows. Since I’ve two arrows up and my CF is 25 based on the suggestions, I’ll want a 3.5 IU correction.

Including all that up my whole dose can be 2 IU + 1 IU + 3.5 IU = 6.5 IU. 

Had my blood sugar been decrease than my goal or had I seen downwards arrows, I’d have ended up with a decrease advisable dose.

Simply to make it possible for is smart, let’s do one other instance:

I once more simply rolled off the bed and am about to sit down down for a meal of 20 grams of carbohydrates, however now my blood sugar is 120 mg/dL (6.8 mmol/l) with one arrow straight down.

All that modified in comparison with the final instance is the path of the arrow, which modifications calculation #3.

Since I now have one arrow straight down and my CF is 25, based on the suggestions I’ll want a -2.5 IU correction.

Including all that up, my new whole dose can be 2 IU + 1 IU – 2.5 IU = 0.5 IU 

Phew, that’s quite a lot of math. Try the following part on how I’d simplify it.

My recommendation for utilizing the Dexcom development arrows

The endocrine suggestions make full sense to me, however it’s quite a lot of math! In addition they don’t will let you take lower than 0.5 IU in correction (which will be a problem in the event you’re very insulin delicate).

I’d quite use a bolus calculator than do all that math each time I must bolus for a meal or a correction dose. When you’ve got a pump, you probably have a built-in bolus calculator. In case you are on a number of each day injections (MDI) like me, you’ll should look elsewhere.

Previously, I’ve used an app referred to as RapidCalc for these calculations. I now use InPen, a SmartPen that sends information on to my cellphone through Bluetooth and has an related app that calculates doses and retains monitor of IOB.

The InPen app and RapidCalc mainly do the identical as a bolus calculator, apart from truly giving me my dose (please word that the RapidCalc app isn’t FDA-approved).

After ending the bottom calculation in your bolus calculator, you possibly can then manually add within the development arrow correction primarily based in your CF.

Keep in mind to react primarily based on what you’ll be doing the following 1 to 4 hours, not on what you’re doing if you’re about to bolus.

Should you’re planning to train or simply transfer greater than ordinary (like go for a stroll, buying, cleansing, gardening, and so on.) you may not must react as aggressively as the rules state.

Typically, it’s advisable that you simply scale back your bolus and probably additionally your basal (in the event you use a pump) earlier than train. As a result of common fast insulin is energetic within the physique for as much as 4 hours (some even see a tail as much as 6 hours after injection), you must assume earlier than you bolus.

You’ll be able to learn my put up about adjusting insulin for train for a extra in-depth rationalization.

There are new ultra-fast performing insulins accessible now and the endocrine tips don’t work for these. Should you use Afrezza or Fiasp, please know that these insulins peak a lot quicker and making use of the calculations proven above may probably be extraordinarily harmful.

When to NOT use the CGM development arrows

All of the publications advocating for utilizing the development arrows for making insulin changes additionally state that there are some conditions the place you must completely NOT use them or at the least take extreme precautions.

Should you plan on beginning to make changes to your insulin dose utilizing development arrows, please learn these precautions first.

4-hour consuming window

The endocrine society recommends that the development arrows usually are not used throughout the 4 hours after having a meal with a bolus. As a substitute, they suggest the next:

• 2 hours post-meal – Don’t appropriate excessive blood sugars to stop insulin stacking
• 2-4 hours post-meal, blood sugar 150-250 mg/dL (8.3-13.9 mmol/l) with one or two arrows up – Think about using CF to regulate
• 2-4 hours post-meal, blood sugar >250 mg/dL (13.9 mmol/l) with one or two arrows up – Affirm with a fingerstick, check for ketones (if >300 mg/dL/16.7 mmol/l), appropriate utilizing injections, if after 1 hour you continue to see two arrows up, repeat
• 2-4 hours post-meal, blood sugar close to 150 mg/dL (8.3 mmol/l) with one arrow barely down – Examine once more in 30-min
• 2-4 hours post-meal, blood sugar close to 150 mg/dL (8.3 mmol/l) with one or two arrows down – Examine once more in 15-min
• 2-4 hours post-meal, blood sugar close to 100 mg/dL (5.6 mmol/l) with one arrow barely down OR one arrow down – Think about consuming 15 g of carbs, recheck in 20-min. If >70 mg/dL (3.9 mmol/l) and downward arrows, affirm with a fingerstick and contemplate one other 15 g of fast-acting carbs 
• 2-4 hours post-meal, blood sugar close to 100 mg/dL (5.6 mmol/l) with two arrows down – Observe the directions above (f) however eat 30 g carbs

Quickly rising blood sugar

Should you see 2 arrows up in your receiver or app earlier than a meal, it’s advisable that you’re diligent along with your pre-bolus and inject your insulin 15 to twenty min earlier than consuming.

Quickly lowering blood sugar

Should you see 2 down in your receiver or app earlier than a meal, it’s advisable that you simply wait and inject your insulin if you begin consuming or in the event you’re near 150 mg/dL (8.3 mmol/l) maintain off and don’t inject till you see your BGs leveling off.

Fragile / older adults

For fragile or older adults, the endocrine society recommends a much less aggressive insulin dose adjustment to restrict the chance of hypoglycemia.

For upward rising arrows, they suggest a 50% discount of the advised adjustment (e.g. from 1 IU to 0.5 IU) and for downward arrows, they suggest a 50% enhance in discount (e.g. from 1 IU to 2 IU).

Sick day administration and medicine issues

Sure drugs, each prescription and OTC, can intrude along with your CGM readings, and development arrows ought to consequently not be used for insulin changes. Moderately than relying fully in your CGM, accompany your CGM readings with finger sticks. 

All the time use widespread sense earlier than dosing

As with all device in our diabetes device package, I’d encourage you to by no means simply apply the suggestions blindly.

When you’ve got a sense that the advisable dose could be off, typically counting on how nicely you recognize your physique is the way in which to go. And though the Dexcom G5 and G6 CGMs are accredited for dosing by the FDA, they will typically be inaccurate, so I’ll at all times confirming with a fingerstick earlier than making any giant dosing changes.