As Sarah has not taken rapid-acting insulin pre-meal before, her sensitivity to this insulin is not known. To get a “ball park” idea the amount of insulin you could use the Rule of 500 (see Chapter IV, Section D in module).
At present her TDD is 22 units. 500 ÷ 22 = 22.7, rounded to 23
Therefore, according to the calculation, Sarah would take 1 unit of insulin for every 23 grams of carbohydrate.
Her supper carbohydrate is 65 grams 65 ÷ 23 = 2.8
Therefore, you could recommend 2-3 units as the initial dose of rapid-acting insulin pre-supper. The follow-up plan with Sarah could include the following:
Record food or grams of CHO eaten at supper for a few days on the new insulin dose Test 2 hours post supper and at bedtime to assess the new insulin’s effectiveness If post meal glucose levels are not dropping to 10 or less, increase the dose of rapid-
acting insulin by 1 unit after 3 test days
If evening glucose levels are too low or she has symptoms of hypoglycemia, reduce the pre-supper dose of rapid-acting insulin by 1 unit
ANSWER - CASE #4
When switching from intermediate-acting insulin to Lantus, it is recommended that the total dose of intermediate-acting insulin be reduced by 20% and the Lantus be given as a single dose. John prefers to take this insulin at bedtime. An alternative could be a morning injection of long-acting as Lantus is usually a once a day injection as long as it is given daily at the same time. The following recommendations are based on the injection occurring at bedtime.
Total dose of N per day = 36 units 20% of this dose = 7.2 units
Recommended starting dose of Lantus = 29 units Advice to John
1. First avoid hypoglycemia. If he has night-time or early morning hypoglycemia symptoms, reduce the Lantus by 10% or 3 units.
2. Check a glucose level around 3 am to ensure he is not missing hypoglycemia.
3. If there is no hypoglycemia and after 3-4 days on the starting dose, the fasting glucose levels are high (>7 mmol/L), increase Lantus by 3 units. Wait 3-4 days between each insulin
increase. He may wish to check another 3 a.m. glucose level before making further increases. 4. He may find his pre-supper glucose readings become elevated as he no longer has
intermediate acting insulin in morning. He will likely need to start on a pre-noon dose of H. This change will require a physician’s order. Ask John to do some 2 hr pc lunch and ac supper results, to determine whether he needs to start a pre-noon dose of H. This information will be valuable for the physician determine what he needs to order.
5. If he is presently taking an afternoon snack, keep it in for now, but the need for the snack should be reassessed.
ANSWER - CASE #5
Using the Rule of 500 to determine how many grams CHO for each unit of insulin. TDD = 7 + 10 + 32 = 49
500 49 = 10.2
Therefore, for every 10 grams CHO he would use 1 unit of insulin.
It will be easier to assess the effectiveness of this recommendation if he agrees to use close to the same amount of carbohydrate for a few days. So, if he agrees to say about 70 grams, then he would use 7 units of H pre-noon. Advise John to check his 2 hr pc noon meal blood glucose levels. If the results fall between the target of 7-10, then it will confirm to John that he is using the correct amount of insulin for CHO eaten.
If he seems unsure about carbohydrate counting or needs more information/support, make a referral to the dietitian. . He has the option to add extra carbohydrate at his noon meal to compensate for the extra calories he has lost with the elimination his afternoon snack.
ANSWER - CASE #6
First calculate John’s total daily dose TDD = 7+10+8+32 = 57 units
Use the rule of 100 as he is using rapid acting insulin. 100 57 = 1.75
This means 1 unit of insulin will drop his blood glucose approximately 1.75 mmol/L
To create a grid the 1.75, could be rounded to up to 2 mmol/L. If John has a history of severe low glucose levels, hypoglycemia unawareness or is nervous about being “too low” you could use a larger range for the dose changes; for example, 3 mmol steps. Or, you could set the target glucose level higher; for example, to 8 mmol/L.
Grid using 1 unit will yield a decrease of approximately 2 mmol/L for morning insulin; the grid would be as follows:
Blood Glucose Range Insulin Dose
< 4.0* 6 4.1 – 7.0 7 7.1 – 9.0 8 9.1 – 11.0 9 11.1 – 13.0 10 13.1 – 15.0 11 > 15.1 12
Note: As part of client education, advise treatment of hypoglycemia and stabilization of blood glucose level before taking insulin and before deciding on the dose. Some clients may need less than the lowest amount on the grid.
If John does not want to use a written grid, he would proceed as follows: Blood glucose = 12.6
Target glucose = 7
Difference = 12.6 - 7 = 5.6
Divide the difference by his correction factor: 5.6/1.75 = 3.2, rounded to 3 Add 3 units to his base dose of 7 = 10 units Humalog to be taken pre-breakfast OR
He could use the rounded correction factor of 2 mmol/L drop for 1 unit of insulin 5.6 2 = 2.8, round up to 3 additional units added to the base dose of Humalog.
If John was using a short-acting insulin, the TDD would be divided into 85 instead of 100. So the calculation would be:
85/57 (total daily dose of insulin) = 1.5
The grid below for short-acting illustrates blood glucose ranges of 1.5 mmol and insulin dose increments of one unit.
Blood Glucose Range Insulin Dose
< 4.0 6 4.1 – 7.0 7 7.1 – 8.5 8 8.5-10.0 9 10.1-11.5 10 11.6-13.0 11 > 13.1 12
ANSWER - CASE #7
Mike is currently using a TDD of 48 units of insulin. This is about 0.6 units per kg and it is allbasal insulin with no insulin for his meals. The usual expected insulin requirement is about 0.5 to 1.0 units/kg. His BMI is 23 so you would not expect insulin resistance and a higher dose needed related to his weight.
He could increase his doses of N further, but considering his A1c and his only insulin is basal insulin, he would likely gain greater benefit from starting to use pre-meal insulin.
Review current his current patterns in his blood glucose records. The overall picture is too high. Highest pattern is fasting with a bedtime to fasting rise.
Breakfast to noon – a decrease by noon although not to target.
Noon to supper – pattern remains similar (1 elevation by supper, could explore reason). Supper to bedtime – general lowering, although not to target.
For extra information to guide IDA, could also suggest Mike check blood glucose 2 hrs pc when pre-meal blood glucose levels come closer to target.
Discuss with Mike his thoughts on the use of rapid/short-acting insulin with meals. As he has only used intermediate insulin, he may be anxious about using these insulins.
Possible choices to manage patterns– these may need to be done in steps, as Mike is ready. Increased fasting blood glucose level – with an average 5 mmol/l rise overnight, if this was
lowered, it may assist with noon and other times of the day as a domino effect occurs. Since N at supper is already fairly large, consider moving the N to bedtime. He may be more comfortable with decreasing it 10% initially until he gains experience with this move. Consider with this move the effect on the breakfast to noon blood glucose level pattern. With this move, some rapid or short-acting insulin will be required at supper. RNs need to
keep current with EDS requirements of the Saskatchewan Drug Plan.
You will need to determine how much of the short or rapid-acting insulin to start to cover the supper carbohydrate intake. A dietitian will be able to help you determine his usual intake. You could begin with a conservative estimate of 1 unit for 20 grams of
carbohydrate and adjust as needed.
To determine the correction dose of rapid or short-acting insulin, consider the rule of 100 for rapid or 85 for short: 100/48 = 2.08, round to 2. 1 unit of insulin will decrease the glucose level by 2 mmol/L. His insulin grid will change by 2 unit increments.
See what this move does however it is likely that Mike will also need to consider using some meal insulin at other times of the day.
ANSWER - CASE #8
Two things suggest that Milly may be having night-time hypoglycemia: the restlessness during the night and “new” higher fasting readings. Ideally it would be useful for Milly to test a few glucose readings at bedtime, 3 a.m. and fasting to see if there is a trend of lower blood glucose overnight. In your assessment also consider:
What does Milly eat at bedtime – if she does snack o Is the carbohydrate consistent?
o How much carbohydrate does she eat?
o Does she use a combination of protein and carbohydrate? o Does she sometimes miss an evening snack?
o Do any of these variables correlate with the symptoms or high fasting readings? Is Milly physically active in the daytime (especially later afternoon) or evenings? Is
anything different on the nights when Milly is active in the day/evenings – lower pre- bedtime readings, different fasting glucose levels the following mornings, correlation between evening activity and night-time symptoms?
Also, she could reduce her evening N to see if the night-time symptoms disappear.
If the night-time symptoms disappear and the fastings remain elevated, she may need to move her N from supper to bedtime to prolong the action towards morning without risking hypoglycemia with the higher doses. Changing the timing of the insulin requires a physician’s order. She may need to decrease her dose of N when the timing is changed. Also look at the impact of the potentially lower fasting reading on the daytime insulin doses.
Milly and her doctor may also consider use of a long-acting insulin analogue as EDS status is now available in Saskatchewan for Lantus42
42 See Saskatchewan Exception Drug Status Program for current information: http://formulary.drugplan.health.gov.sk.ca/ cited 26 march 2009
ANSWER - CASE #9
Consider as you have your discussion with Fred:
What is Fred willing to do? What are his goals for himself? Is he happy with what is happening? Does he have some ideas on what he could do?
Explore his concerns around insulin injections as the options for improving control involving more injections – what does he currently use – syringes, pens? Injection sites?
Technique? Fears he has?
The large single morning injection of one insulin may be causing some/all of Fred’s complaints. The N peaks in the afternoon and could cause mid-afternoon hypoglycemia. Review his
usual food intake and activity habits.
Even though the dose of N is large, it may not last long enough to control glucose levels through the night and early morning. This would be responsible for the nocturia and the high fasting glucose levels.
It is likely that Fred would benefit from spreading out his insulin however this will all depend on Fred’s readiness and will likely need to be done in a series of steps, as Fred is ready.
Some options for him to consider:
He currently uses 1.1 units/kg per day which is more than usual considering he is lean. All of his insulin is basal insulin and it is also being used to cover his meals.
The first priority is to reduce the frequency of lows in the afternoon by: increasing the carbohydrate taken in the afternoon
reducing activity
decreasing insulin dose in the morning
Assume Fred is happy with his carbohydrate intake and activity pattern. Lower the morning N by 10% every 3-4 days until unexplained low blood glucose levels are eliminated.
It is likely that at the same time, some N will need to be added at supper. Split the morning N dose between morning (2/3 of the NPH dose) and at supper or bedtime (⅓ of the NPH dose).
You may need to gradually add in pre-meal short or rapid-acting insulin
If he needs short or rapid-acting insulin later, he could use a syringe to measure to keep the number of injections at 2 or 3 per day.
ANSWER CASE - #10
The pattern of Joe’s glucose readings shows the supper N lasts until the following morning with fasting glucose reading at or below the recommended target of 4-7 mmol/L. Glucose levels for the remainder of the day are usually above target and the blood glucose level does rise from supper to bedtime.
Before he changes his insulin, it would be beneficial for Joe to see a dietitian. He can decide whether or not he wants to use an approach of consistent carbohydrate or learn carbohydrate counting. When he has a meal planning method, the pattern of the glucose levels can be reviewed again.
Likely the best option for Joe to consider will be pre-meal rapid acting insulin to handle the meal time carbohydrate. He could consider moving his supper N to bedtime or using extended long- acting insulin analogue.
Remember he is used to taking insulin twice daily and you may need to approach change
gradually. Depending on his response to proposed changes and options, one choice, initially, may be to added, one insulin at a time, such as adding R to his supper insulin dose. The N may need to be reduced as the HS blood glucose levels will likely improve.