The loop status is shown on the main screen with one of the icons below.
AAPS offers several loop modes, such as Open Loop (7), Closed Loop (1) and Low Glucose Suspend (LGS - 2).
See AAPS Screens > The Homescreen > Loop status for information on how to select the loop mode.
(KeyAapsFeatures-OpenLoop)=
AAPS continuously evaluates all available data (IOB, COB, BG...) and makes treatment suggestions (temporary basal rates) on how to adjust your therapy if necessary.
The suggestions will not be executed automatically (as in closed loop). The suggestions have to be enacted by the user manually into the pump (if using virtual pump) or by using a button if AAPS is connected to a real pump.
This option is for getting to know how AAPS works or if you are using an unsupported pump. You will be in Open Loop, no matter what choice you make here, until the end of Objective 5.
(KeyAapsFeatures-LGS)=
In this mode, maxIOB is set to zero.
This means that if blood glucose is dropping, AAPS can reduce the basal for you. But if blood glucose is rising, no automatic correction will be made. Your basal rates will remain the same as defined in your current Profile. Only if IOB is negative (from a previous Low Glucose Suspend) additional insulin will be given to lower BG.
This mode is available starting at Objective 6.
(KeyAapsFeatures-ClosedLoop)=
AAPS continuously evaluates all available data (IOB, COB, BG...) and automatically adjusts the treatment if necessary (i.e. without further intervention by you) to reach the set target range or value (bolus delivery, temporary basal rate, insulin switch-off to avoid hypo etc.).
The Closed Loop works within numerous safety limits, which can be set individually.
Closed Loop is only possible if you are in Objective 7 or higher and use a supported pump.
(Open-APS-features-autosens)=
- Autosens is an algorithm which looks at blood glucose deviations (positive/negative/neutral).
- It will try and figure out how sensitive/resistant you are based on these deviations.
- The oref implementation in OpenAPS runs off a combination of 24 and 8 hours worth of data. It uses either one which is more sensitive.
- In versions prior to AAPS 2.7, the user had to choose between 8 or 24 hours manually.
- From AAPS 2.7 on Autosens in AAPS will switch between a 24 and 8 hours window for calculating sensitivity. It will pick whichever one is more sensitive.
- If users have come from oref1 they will probably notice the system may be less dynamic to changes, due to the varying of either 24 or 8 hours of sensitivity.
- Changing a cannula or changing a profile will reset Autosens ratio back to 100% (a percentual profile switch with duration won't reset autosens).
- Autosens adjusts your basal and ISF (i.e.: mimicking what a Profile shift does).
- If continuously eating carbs over an extended period, Autosens will be less effective during that period as carbs are excluded from BG delta calculations.
(Open-APS-features-super-micro-bolus-smb)=
SMB, the shortform of Super micro bolus, is an OpenAPS feature introduced from 2018 onwards, within the Oref1 algorithm. In contrast to AMA, SMB does not use temporary basal rates to control glucose levels, but mainly small super micro boluses. In situations where AMA would add 1.0 IU insulin using a temporary basal rate, SMB delivers several super micro boluses in small steps at 5 minute intervals, e.g. 0.4 IU, 0.3 IU, 0.2 IU and 0.1 IU. At the same time (for safety reasons) the actual basal rate is set to 0 IU/h for a certain period to prevent overdose ('zero-temping'). This allows the system to adjust the blood glucose faster than with the temporary basal rate increase in AMA.
Thanks to SMB, it may be sufficient for meals containing only "slow" carbs to inform the system of the planned amount of carbohydrate and leave the rest to AAPS. However, this may lead to higher postprandial (post-meal) peaks because pre-bolusing isn’t possible. Or you can give, if necessary with pre-bolusing, a start bolus, which only partly covers the carbohydrates (e.g. 2/3 of the estimated amount) and let SMB deliver the rest of the insulin.
SMBs are shown on the main graph with blue triangles. Tap on the triangle to see how much insulin was delivered, or use the Treatments tab.
SMB's features contain some safety mechanisms:
-
Largest single SMB dose
The largest single SMB dose can only be the smallest value of:- value corresponding to the current basal rate (as adjusted by autosens) for the duration set in "Max minutes of basal to limit SMB to", e.g. basal quantity for the next 30 minutes, or
- half the amount of insulin currently required, or
- the remaining portion of your maxIOB value in the settings.
-
Low temp basal rates
Low temporary basal rates (called 'low temps') or temporary basal rates at 0 U/h (called 'zero-temps') are activated more in SMB. This is by design for safety reasons and has no negative effects if the Profile is set correctly. On the main graph, the IOB curve (yellow thin line) is more meaningful than the course of the temporary basal rates. -
Un-Announced Meals
Additional calculations to predict the course of glucose, e.g. by UAM (un-announced meals). Even without manual carbohydrate input from the user, UAM can automatically detect a significant increase in glucose levels due to meals, adrenaline or other influences and try to adjust this with SMB. To be on the safe side this also works the other way round and can stop the SMB earlier if an unexpectedly rapid drop in glucose occurs. That's why UAM should always be active at SMB.
You must have started objective 9 to use SMB.
See also :
The settings for OpenAPS SMB are described below.
(Open-APS-features-max-u-h-a-temp-basal-can-be-set-to)=
This safety setting determines the maximum temporary basal rate the insulin pump may deliver. It is also known as max-basal.
The value is measured in units per hour (U/h). It is advised to set this to something sensible. A good recommendation for setting this parameter is:
MAX-BASAL = HIGHEST BASAL RATE x 4
For example, if the highest basal rate in your profile was 0.5 U/h you could multiply that by 4 to get a value of 2 U/h.
AAPS limits this value as a 'hard limit' according to Preferences > Treatments safety > Patient Type. The hard limits are as follows:
- Child: 2
- Teenager: 5
- Adult: 10
- Insulin-resistant adult: 12
- Pregnant: 25
See also overview of hard-coded limits.
(Open-APS-features-maximum-total-iob-openaps-cant-go-over)=
This value determines the maximum Insulin on Board (basal and bolus IOB) that AAPS will remain under while running in closed loop mode. It is also known as maxIOB.
If the current IOB (e.g. after a meal bolus) is above the defined value, the loop stops dosing insulin until the IOB limit is below the given value.
A good start for setting this parameter is:
maxIOB = average mealbolus + 3x max daily basal
Be careful and patient when adjusting your max-IOB. It is different for everyone and can also depend on the average total daily dose (TDD).
AAPS limits this value as a 'hard limit' according to Preferences > Treatments safety > Patient Type. The hard limits are as follows:
- Child: 3
- Teenager: 7
- Adult: 12
- Insulin resistant adult: 25
- Pregnant: 40
See also overview of hard-coded limits.
Note : When using SMB, the max-IOB is calculated differently than in AMA. In AMA, maxIOB is a safety-parameter for basal IOB, while in SMB-mode, it also includes bolus IOB.
See also OpenAPS documentation for SMB.
This is the DynamicISF feature. When enabled, new settings become available. Settings are explained on the DynamicISF page.
This is the Autosens feature. When using DynamicISF, Autosens can not be used, since they are two different algorithms altering the same variable (sensitivity).
Autosens looks at blood glucose deviations (positive/negative/neutral). It will try and figure out how sensitive/resistant you are based on these deviations and adjust basal rate and ISF based on these deviations.
When enabled, new settings become available.
If this option is enabled, the sensitivity detection (autosens) can raise the target when sensitivity is detected (below 100%). In this case your target will be raised by the percentage of the detected sensitivity.
If the target is modified due to sensitivity detection, it will be displayed with a green background on your home screen.
This setting is available when one of "Enable dynamic sensitivity" or "Enable Autosens feature" are enabled.
If this option is enabled, the sensitivity detection (autosens) can lower the target when resistance is detected (above 100%). In this case your target will be lowered by the percentage of the detected resistance.
This setting is available when one of "Enable dynamic sensitivity" or "Enable Autosens feature" are enabled.
Enable this to use SMB functionality. If disabled, no SMBs will be given.
When enabled, new settings become available.
If this setting is enabled, SMBs will still be delivered even if the user has selected a high Temp Target (defined as anything above 100mg/dL or 5.6mmol/l, regardless of Profile target 'High Temp Target'). Please exercise caution when enabling this setting as SMB can be overly aggressivley if the user's settings are not correct or if the user's Profile is subject to frequent variation like with children.
If this option is disabled SMBs will not be delivered when a High Temp Target has been selected within AAPS. For example, SMBs will be disabled by selecting TT Activty. SMBs will always be disabled regardless of what other condition is trying to enable SMB apart from 'TT Eating Soon' (or if TT is set below 100mg/dL or 5.6mmol/l) which may deliver SMBs to drive BG to desired target level depending on BG.
If this setting is enabled, SMB is activated always regardless of independent of COB or Temp Targets. The rest of the enabled settings below under Preferences will have no effect.
However, if selected along with Enable SMB with temp targets as disabled under settings and a high Temp Target is set, SMBs will be disabled. This setting's combination is important and seems to be preferred by some AAPS users to avoid AAPS delivering too many SMBs and prevent hypoglycemia.
This setting is only available if AAPS detects that you are using a reliable BG source, with advanced filtering. FreeStyle Libre 1 is not considered a reliable source due to the risk of infinitely repeating old BG data in case of sensor failure.
Noisy data could cause AAPS to believe BG is rising really fast, resulting in the administration of unnecessary SMBs. For more information about noise and data smoothing, see here.
If this setting is enabled, SMB is enabled when the COB is greater than 0.
This setting is not visible if "Enable SMB always" is switched on.
If enabled, SMB is enabled for 6h after carbohydrates are announced, even if COB has reached 0.
For safety reasons, this setting is only available if AAPS detects that you are using a reliable BG source. It is not visible if "Enable SMB always" is switched on.
This setting is only available if AAPS detects that you are using a reliable BG source, with advanced filtering. FreeStyle Libre 1 is not considered a reliable source due to the risk of infinitely repeating old BG data in case of sensor failure.
Noisy data could cause AAPS to believe BG is rising really fast, resulting in the administration of unnecessary SMBs. For more information about noise and data smoothing, see here.
This setting is not visible if "Enable SMB always" is switched on.
This feature limits the frequency of SMBs. This value determines the minimum time between SMBs. Note that the loop runs every time a glucose value comes in (generally 5 minutes). Subtract 2 minute to give loop additional time to complete. E.g. if you want SMB to be given every loop run, set this to 3 minutes.
Default value: 3 min.
(Open-APS-features-max-minutes-of-basal-to-limit-smb-to)=
This is an important safety setting. This value determines how much SMB can be given based on the amount of basal insulin in a given time, when it is covered by COBs.
Making this value larger allows the SMB to be more aggressive. You should start with the default value of 30 minutes. After some experience, increase the value in 15 minutes increments and observe the effects over multiple meals.
It is recommended not to set the value higher than 90 minutes, as this would lead to a point where the algorithm might not be able to accommodate a decreasing BG with 0 U/h basal ('zero-temp'). You should also set alarms, especially if you are still testing new settings, which will warn you well before a hypo.
Default value: 30 min.
This setting allows to adjust the strength of SMB during UAM, when there are no more carbs.
Default value : the same as Max minutes of basal to limit SMB to.
This setting is only visible if "Enable SMB" and "Enable UAM " are switched on.
With this option enabled, the SMB algorithm can recognize unannounced meals. This is helpful if you forget to tell AAPS about your carbs or estimate your carbs wrong and the amount of entered carbs is wrong or if a meal with lots of fat and protein has a longer duration than expected. Without any carb entry, UAM can recognize fast glucose increase caused by carbs, adrenaline, etc., and tries to adjust it with SMBs. This also works the opposite way: if there is a fast glucose decrease, it can stop SMBs earlier.
Therefore, UAM should always be activated when using SMB.
(key-aaps-features-minimal-carbs-required-for-suggestion)=
Minimum grams of carbs to display a carbs suggestion alert. Eating of additional carbs will be suggested when the reference design detects that it requires carbs. In this case you will receive a notification which can be snoozed for 5, 15 or 30 minutes.
Carb required notifications can be pushed to Nightscout if wished, in which case an announcement will be shown and broadcast.
In any case, the required carbs will be displayed in the COB section on your home screen.
You can read more here : OpenAPS docs.
Always use short average delta instead of simple data If you enable this feature, AAPS uses the short average delta/blood glucose from the last 15 minutes, which is usually the average of the last three values. This helps AAPS to be steadier with noisy data sources like xDrip+ and Libre.
Max daily safety multiplier This is an important safety limit. The default setting (which is unlikely to need adjusting) is 3. This means that AAPS will never be allowed to set a temporary basal rate that is more than 3x the highest hourly basal rate programmed in a user’s pump and/or profile. Example: if your highest basal rate is 1.0 U/h and max daily safety multiplier is 3, then AAPS can set a maximum temporary basal rate of 3.0 U/h (= 3 x 1.0 U/h).
Default value: 3 (shouldn’t be changed unless you really need to and know what you are doing)
Current Basal safety multiplier This is another important safety limit. The default setting (which is also unlikely to need adjusting) is 4. This means that AAPS will never be allowed to set a temporary basal rate that is more than 4x the current hourly basal rate programmed in a user’s pump and/or profile.
Default value: 4 (shouldn’t be changed unless you really need to and know what you are doing)
(Open-APS-features-advanced-meal-assist-ama)=
AMA, the short form of "advanced meal assist" is an OpenAPS feature from 2017 (oref0). OpenAPS Advanced Meal Assist (AMA) allows the system to high-temp more quickly after a meal bolus if you enter carbs reliably.
You can find more information in the OpenAPS documentation.
This safety setting helps AAPS from ever being capable of giving a dangerously high basal rate and limits the temp basal rate to x U/h. It is advised to set this to something sensible. A good recommendation is to take the highest basal rate in your profile and multiply it by 4 and at least 3. For example, if the highest basal rate in your profile is 1.0 U/h you could multiply that by 4 to get a value of 4 U/h and set the 4 as your safety parameter.
You cannot choose any value: For safety reason, there is a 'hard limit', which depends on the patient age. The 'hard limit' for maxIOB is lower in AMA than in SMB. For children, the value is the lowest while for insulin resistant adults, it is the biggest.
The hardcoded parameters in AAPS are:
- Child: 2
- Teenager: 5
- Adult: 10
- Insulin resistant adult: 12
- Pregnant: 25
See also overview of hard-coded limits.
This parameter limits the maximum of basal IOB where AAPS still works. If the IOB is higher, it stops giving additional basal insulin until the basal IOB is under the limit.
The default value is 2, but you should rise this parameter slowly to see how much it affects you and which value fits best. It is different for anyone and also depends on the average total daily dose (TDD). For safety reason, there is a limit, which depends on the patient age . The 'hard limit' for maxIOB is lower in AMA than in SMB.
- Child: 3
- Teenager: 5
- Adult: 7
- Insulin resistant adult: 12
- Pregnant: 25
See also overview of hard-coded limits.
Here, you can choose, if you want to use the sensitivity detection autosens or not.
If you have this option enabled, autosens can adjust targets (next to basal and ISF), too. This lets AAPS work more 'aggressive' or not. The actual target might be reached faster with this.
- Normally you do not have to change the settings in this dialogue!
- If you want to change them anyway make sure to read about details in OpenAPS docs and to understand what you are doing.
Always use short average delta instead of simple data If you enable this feature, AAPS uses the short average delta/blood glucose from the last 15 minutes, which is usually the average of the last three values. This helps AAPS to work more steady with noisy data sources like xDrip+ and Libre.
Max daily safety multiplier This is an important safety limit. The default setting (which is unlikely to need adjusting) is 3. This means that AAPS will never be allowed to set a temporary basal rate that is more than 3x the highest hourly basal rate programmed in a user’s pump. Example: if your highest basal rate is 1.0 U/h and max daily safety multiplier is 3, then AAPS can set a maximum temporary basal rate of 3.0 U/h (= 3 x 1.0 U/h).
Default value: 3 (shouldn’t be changed unless you really need to and know what you are doing)
Current Basal safety multiplier This is another important safety limit. The default setting (which is also unlikely to need adjusting) is 4. This means that AAPS will never be allowed to set a temporary basal rate that is more than 4x the current hourly basal rate programmed in a user’s pump.
Default value: 4 (shouldn’t be changed unless you really need to and know what you are doing)
Bolus snooze dia divisor The feature “bolus snooze” works after a meal bolus. AAPS doesn’t set low temporary basal rates after a meal in the period of the DIA divided by the “bolus snooze”-parameter. The default value is 2. That means with a DIA of 5h, the “bolus snooze” would be 5h : 2 = 2.5h long.
Default value: 2
(Open-APS-features-overview-of-hard-coded-limits)=
| Child | Teenager | Adult | Insulin resistant adult | Pregnant | |
|---|---|---|---|---|---|
| MAXBOLUS | 5 | 10 | 17 | 25 | 60 |
| MINDIA | 5 | 5 | 5 | 5 | 5 |
| MAXDIA | 9 | 9 | 9 | 9 | 10 |
| MINIC | 2 | 2 | 2 | 2 | 0.3 |
| MAXIC | 100 | 100 | 100 | 100 | 100 |
| MAXIOB_AMA | 3 | 5 | 7 | 12 | 25 |
| MAXIOB_SMB | 7 | 13 | 22 | 30 | 70 |
| MAXBASAL | 2 | 5 | 10 | 12 | 25 |