Insulin is a hormone that is produced by the b cells of the pancreas. With the help of insulin, glucose enters the muscle, liver and adipose tissue, where it is used either as an energy source or is stored as glycogen.
Since the type 1 diabetes in se pancreatic b-cells die and insulin is not produced, the only way to maintain a normal blood glucose levels – insulin lifelong administration itself.
In a healthy person, insulin is produced continuously at a rate of about 1 U per hour. This secretion is called the background (basal): its role is to maintain a normal level of glucose in the blood between meals and at night.
In response to food intake, the rate of insulin secretion increases dramatically. This insulin secretion is called prandial ( bolus ): its role is to maintain normal glucose levels after meals.
There are 2 ways to simulate the physiological secretion of insulin:
- Multiple injection regimen (synonyms: bas- bolus regimen, intensified insulin therapy regimen):
- administration of basal insulin 1-2 times a day in combination with bolus insulin before each meal.
- Continuous continuous infusion of insulin with an insulin pump (synonym: insulin pump therapy):
- the introduction of an ultrashort insulin analogue or human short insulin (rarely) in a continuous mode;
- In some pumps there is the possibility of continuous monitoring of blood glucose levels (with the additional installation of the sensor).
Calculation of insulin dose in the mode of multiple injections
Basal insulin dosage:
- makes up 30-50% of the total daily dose;
- administered 1 or 2 times a day, depending on the profile of insulin action at the same time;
- dose adequacy is assessed by achieving the target fasting blood glucose level and before main meals;
- once every 1-2 weeks, it is advisable to measure glucose at 2-4 am at night to rule out hypoglycemia;
- dose adequacy is assessed by achieving the target fasting blood glucose level (for the insulin dose given at bedtime) and for the main meals (for the insulin dose given before breakfast);
- with prolonged physical exertion, a dose reduction may be required.
Correction of the dose of basal insulin:
Long-acting insulin – regardless of the time of introduction, the correction is carried out according to the average fasting glucose level for the previous 3 days. Correction is carried out at least 1 time per week:
- e fusion was hypoglycemia, the dose is reduced to 2 U init;
- if the average fasting glucose in the target range, then increasing the dose is not required;
- if the average fasting glucose is higher than the target, then it is necessary to increase the dose by 2 For example, fasting blood glucose values are 8.4 and 7.2 mmol / l. The goal of treatment is fasting glucose 4.0 – 6.9 mmol / l. The average value – 7.2 mmol / l – is higher than the target, therefore, it is necessary to increase the dose by 2 Units.
NPH-insulin – the algorithm for titration of basal insulins is the same:
- the titration algorithm for the dose administered before bedtime is similar to the titration algorithm for long-acting insulins;
- The titration algorithm for the dose administered before breakfast is similar to the titration algorithm for long-acting insulins, however, it is performed according to the median blood glucose value before dinner.
The dose of prandial insulin is at least 50% of the total daily dose and is administered before each meal containing carbohydrates.
The dose depends on :
- the amount of carbohydrate (HE) that you plan to eat;
- planned physical activity after insulin administration (may require a dose reduction);
- dose adequacy is assessed by reaching the target blood glucose level 2 hours after a meal;
- individual insulin requirements by 1 XE (in the morning hours, 1 XE usually requires more insulin than during the day and in the evening). The calculation of the individual need for insulin for 1 XE is carried out according to the “Rule 500”: 500 / total daily dose = 1 U of inits Prandial insulin is necessary for the absorption of X g of carbohydrates.
Example: total daily dose = 60 U. 500/60 = 1 U Prandial insulin is necessary for the assimilation of 8.33 g of carbohydrates, which means that for the assimilation of 1 XU (12 g) 1.5 U Units are needed prandial If the carbohydrate content in the food is 24 g (2 XE), 3 Units of injections should be entered . prandial insulin.
A dose of corrective insulin (short-acting insulin or an analogue of ultrashort-acting insulin) is introduced to correct an elevated blood glucose level (in the morning, before or after the next meal, or at night), and is also necessary if there is a concomitant inflammatory disease or infection.
Methods for calculating the adjustment dose of insulin
There are several ways to calculate the adjustment dose, you need to use the most convenient and understandable for you.
Method 1. The correction dose is calculated on the basis of the total daily insulin dose (basal and prandial insulin):
- with a glycemia level of up to 9 mmol / l, additional insulin administration (“shotgun”) is not required;
- with a blood glucose level of 10–14 mmol / l, the adjustment dose (“pinhole”) is 5% of the total daily insulin dose. At the level of glycemia above 13 mmol / l, control of acetone in the urine is necessary;
- with a blood glucose level of 15–18 mmol / l, the adjustment dose (“pinhole”) is 10% of the total daily insulin dose. At the level of glycemia above 13 mmol / l, control of acetone in the urine is necessary;
- when the blood glucose level is more than 19 mmol / l, the adjustment dose (“pinhole”) is 15% of the total daily insulin dose. When the blood glucose level is above 13 mmol / l, control of acetone in the urine is necessary.
Method 2. The calculation of the adjustment dose takes into account the total daily dose and the coefficient of insulin sensitivity or correction coefficient (individual indicator).
The sensitivity coefficient shows how much mmol / L one unit of insulin lowers blood glucose levels. When calculating the following formulas are used:
- “Rule 83” for short-acting insulin:
coefficient of sensitivity ( mmol / l) = 83 / per total daily dose of insulin - “Rule 100” for an ultra-short acting insulin analog:
sensitivity coefficient ( mmol / l) = 100 / per total daily insulin dose
Calculation example
The total daily dose of insulin is 50 U. You get an analogue of ultrashort-acting insulin, which means that the sensitivity coefficient is 100 divided by 50 = 2 mmol / l.
Suppose the glycemia level is 12 mmol / l, the target level is 7 mmol / l, thus, it is necessary to reduce the level of glycemia by 5 mmol / l. To do this, you need to enter 5 mmol / l divided by 2 mmol / l = 2.5 U (rounded to 3 U , unless your pen is not in increments of 0.5 units ) of ultrashort insulin.
After the introduction of the adjustment dose of short-acting insulin, it is necessary to wait 3-4 hours and 2-3 hours – after the introduction of the ultrashort analogue. Only after this, again measure the level of glucose in the blood and again, if necessary, enter the adjustment dose.
In the presence of acetone, the adjustment dose will be greater due to a decrease in insulin sensitivity. If there are symptoms of ketoacidosis, call the ambulance team.