Current insulin pens are more convenient than injections with syringes, but they could do so much more. They could be designed like today's smart insulin pumps, and could even be designed to be far more intelligent so they really improve control.
Today's insulin pumps collect the data needed to improve control: basal doses, carb boluses, correction boluses, carb intake, and blood sugars. New features guide the user in meal and correction boluses, and protect against insulin stacking with the bolus on board (BOB) feature. Activity is not yet tracked in any device, but could easily be incorporated in the pen as shown below.
A smart insulin pen would incorporate the following:
The pen's dimensions are slightly thicker and longer than a typical pen as shown in the diagram.
- A sliding cover reveals the needle or can be extended and locked to protect the needle -
- a standard pen needle
- 200 unit custom refillable insulin vial for storage of rapid insulin
- a custom 3/8" x 3/16" motor
- a finely threaded plunger capable of delivering exact insulin doses in increments as small as 0.1 or 0.2 of a unit - See Animation
- back button - See Animation
- Bluetooth communication
- an 1 5/8" x 5/8" LCD panel
- dial built into the body to change selections or numerical values - See Animation
- select button See Animation
- dedicated computer chip
- non-volatile memory
- AAA battery
- blood glucose meter with 5 second micro-draw strip See Animation
- rubber tipped cap that can be slid into the slot for the meter strip with a flexible attachment to the pen barrel to prevent losing this protective cover
See the pen in action in this simulation.
- Carb factors (from 1:1 to 1:100 grams) and correction factors (from 1:4 to 1:400 mg/dl) can be personalized in the pen by the HCP or the user.
- The boluses given to cover carbs or to lower high blood sugars are stored separately in memory so that the HCP or the user can determine when boluses to cover carbs are too large or small a percentage of TDD and when correction boluses are excessive (make up more than 8% or 10% of the TDD).
- A dial is located to the right of the LCD to scroll to a selection, such as bolus type [carb, correction, or combo], or a carb choice from 300 to 500 personal food selections, Settings are available for time/date, carb factor, correction factor, BG target, duration of bolus activity, and intensity and duration of exercise.
- A button to the right of the turnable dial selects an option, while another button to the left of the LCD is used to escape or return to the previous screen.
- A 300 to 500 food database of favorite carb-containing foods with grams of carb per portion and glycemic index where available. Selections can be personalized via a Bluetooth connection to a PC or Palm device.
- Duration of insulin activity (4 to 6 hours) can be personalized to keep track of how much insulin activity remains from recent boluses. The BOB may be calculated from a Gaussian curve with a staggered start, a time/activity formula, or other appropriate means. If sufficient memory and processing power are available in the pen, a true dynamic insulin curve can be incorporated to track the BOB more accurately.
- Duration of exercise or activity levels can be entered in increments of 5 minutes, while intensity is graded on a 1 to 10 scale.
- Each time a new BG test is done, the LCD will display the current situation and indicate whether more carb intake or a correction bolus is needed. If excess BOB is present, carb or correction doses are reduced appropriately to account for active insulin (this is only when the pen is the only device used for insulin delivery). Alerts and warnings could be set by the user for various reasons, such as missing a bolus for a meal or a cartridge is low.
- Non-volatile memory in the pen tracks time, date, BGs, carb boluses, carb counts, correction doses, exercise or activity, most recent A1c value, as well as battery life and the number of units remaining in the cartridge.
- The user collects time and date of all high blood sugars as well as actual and suspected low blood sugar events, whether or not a BG test was done at the time.
- Bluetooth communication allows secure transfer of pen data to a personal PC, a physician's PC, Palm device, or through a modem to an internet site for analysis.
- Data downloaded from each pen is graded at a central processing site for severity of BG problems to determine need for intervention. Severe BG problems would be emailed or faxed with realistic recommendations to the personal MD and to the user for immediate intervention. Suggestions for handling less severe problems would be sent to the user, parent, or guardian via email or fax as clear, realistic recommendations.
- Clear recommendations for insulin or carb adjustments are made based, among other things, on recent A1c values, variability of current BGs, a determination whether lows or highs are the main problem, and recognition of patterns (low to high, high to low, excessive overnight rise or fall, time at which lows or highs are most common, whether post meal values are quite variable [need for more accurate carb counting], etc.)
Since we wrote this.....
Since we originally wrote this article, there have been some strides in the smart pen market. Take a look at our Insulin Pen Page to see more updated smart insulin pens.