Insulin dose simulations
David Kinshuck
These simulations are teaching tools and are not accurate. For instance, obviously a severe hypo will not lead to an instant recovery as it does in these simulations. Thanks to the 'Flash' community for lots of online help. Simulations written by David Kinshuck
Links to each simulation
Brief explanation of models
Simple model
- Simple model
- exe file for laptop 1mb
- Just adjust the insulin dose by dragging the 'dose' button with your mouse up and down.
- You can calculate what dose of insulin you need to produce a nearly normal glucose level.
- You can adjust the time of the insulin dose, by dragging the 'slider', and you can adjust the dose.
- In addition you can use you mouse to adjust the time of meals, sliding the meals to different times by dragging them with your mouse.
- By adjusting the insulin dose as above (up and down) and change the time by draging the insulin dose button with your mouse you can simulate 'real' injections.
- When you change the time of the meals, the glucose levels goes very
erratic, so you have to adjust the time of the insulin dose, by dragging
the 'dose' button from side to side with your mouse.
In this way you give the insulin before or at the beginning of the meal, to produce a nearly flat glucose level. - The simulation is very inaccurate in certain respects. The simulation allows 'negative' glucose values, which is clearly impossible/inaccurate; it allows a very quick recovery from a very high or low glucose value, whereas in reality at best the patient would be very ill. Each insulin dose produces a consistent effect, and this is not always the case clinically.
Exercise
- Exercise model
- exe file for laptop 1mb
- With this model exercise is added. You need to adjust the insulin dose to prevent a low blood sugar (a hypo) after food.
- You drag in more exercise from the left side of the screen.
- Here it becomes difficult to control the diabetes, as it does for
patients.
You can do this by keeping all the glucose levels high, but of course this damages eyes and kidneys etc...but you will need to reduce insulin levels. - Exercise after meals..you can reduce the rapid-acting insulin.
- Lots of exercise...you will need to reduce the long-acting insuln, the lantus or detemir insulin.
- Walking produces a slight drop in sugar (and insulin levels drop in a non-diabetic person).
- Cycling uphill produces a much greater drop. After lots of cycling, glucose levels drops for hours after the cycling, and you will need to reduce the 'lantus' level to prevent a low glucose level and a hypo episode.
- Each 'walking' of 'cycling' cartoon represents 30-60 minutes exercise.
- Walking is equivalent to any gentle exercise, such as gardening.
- Cycling uphill is equivalent to any vigorous exercise, such as swimming or football.
Exercise, snacks, and boluses model
- exercise, snacks, and boluses model
- as above, but additional snacks
- add insulin boluses to cover the snacks
Adjusting for different patients
- model adjusting for different patients
- A more complicated model
- adjust for 'insulin resistance' etc. Each person has different insulin requirements...you can dial in your patient's estimated requirements and then simulate different meals, different exercise and so on.
- thus very thin patients need much less insulin than those who are over-weight.
- there are more 'help' buttons adjacent to simulation buttons
Working out energy expenditure as well
- working out energy expenditure as well
- A more complicated model
- energy expenditure is included
- an extra large pizza
- you can work out whether you will gain/lose weight each day.
Insulin pump
- insulin pump
- Simulates a very basic insulin pump.
- adjust the basal rate
- adjust the bolus rate
- a computer glitch allows' negative' insulin doses (this is impossible clinically)
- for ease insulin doses at the right end of screen, that is 4-5pm (~17.00hours) control glucose readings on the left side of the screen ( 6-8pm (~19.00hours)
- the simulation is very slow to respond
- you can simulate different types of bolus insulin by giving some insulin with the pre-meal bolus, and some later ( to simulate a square wave or exented wave bolus for instance)
Insulin pump 2
- insulin pump 2
- slightly more elaborate simulation for insulin pump
Insulin pump 3
- insulin pump 3
- exe file for laptop 1mb
- Much more elaborate, but with many limitations.
- Start
- dial in your own normal basal rate
- (top set of blue buttons) on a day you were well controlled
- then put in your basal rates, add your food, add exercise, and readjust your basal and bolus rates.
- see pump paragraphs above
- there are several 'example patients' at the bottom.
How do they work
- The simulations calculate the difference between ideal insulin levels and the diabetic level...that is not natural insulin, but having insulin injections.
- Typical insulin levels have been measured in healthy people and go up with food. They go up more rapidly with fast food like pizza, slower with healthier higher fibre foods. The simulation use a very simplifed formula for calulating this, and cannot accurately simulate the situation in people.
- Glucose levels in diabetes are very reliant on insulin levels. Insulin works more effectively with exercise, and this is simulated in the exercise model.
- Most of the simulations ignore the fact that insulin levels in the non-diabetic vary during the day, for instance they are much lower at certain parts of the night than others. But the insulin pump 3 takes this into account....you dial in your normal basal requirement. All the simulations ignore stress, insulin site problems, and so on.
- But the simulations clearly demonstrates the problems with basal bolus regime (insulin injections must match food intake) and with exercise. The pump simulation is more complicated, but can simulate very accurate glucose control.