A few days ago, a package arrived at my house form Medtronic Minimed.   It included a brand new box of Quick-set infusion sets (my infusion set of choice), and a letter explaining a recall of all sets that have lot numbers starting with the number "8."  According to the letter, Medtronic estimates "that approximately 2% of the "Lot 8" Quick-set infusion sets may not work properly."  And, although "the manufacturing process has been changed and this is no longer a problem," Medtronic is now in the process of replacing all Lot 8 sets.

The problem with the Lot 8 Quick-sets involves ventilation; they may not allow the insulin pump to vent properly.  Medtronic states that "venting is necessary to equalize the pressure in the reservoir compartment with the surrounding atmosphere... [and] If the vent does not work properly, this could potentially result in too much or too little insulin being delivered." 

The website outlines the circumstances in which the clogged vents would cause an over delivery of insulin: "When an infusion set does not vent properly, a rapid increase in altitude could cause too much insulin to be delivered. Examples of this include when an airplane is taking off, and traveling from sea level to a higher elevation, such as when driving up a mountain."   The website also outlines the circumstances where the sets would cause an under delivery of insulin: "When an infusion set does not vent properly, even at stable altitude or stable air pressure, insulin delivery can be interrupted. This happens because the priming process may build up air pressure in the reservoir compartment. The insulin pump could appear to be working properly when it is not. This might result in too little insulin being delivered, which could cause high blood glucose to occur."

Every box of sets in my house was from Lot 8.  In the past month, I have flown on two planes, slept at an elevation of 0 feet, 7500 feet, and 9000 feet, respectfully, and climbed two mountains. One of these mountains was over fourteen thousand feet.  And, in the past month, I have had a lot of highs and a lot of lows.  Now, I highly doubt that I actually had one of the dysfunctional sets.  However, there would be no way to really know!  Even Medtronic writes that, "A significant over delivery of insulin may not be detected until after it has occurred... As always with insulin pump therapy, any interruption in insulin delivery can be detected through frequent blood glucose monitoring."

Whenever something doesn't go according to the plan, whenever my blood sugar is unexpectedly high or low, I work through a sort of process in order to determine what went wrong.  There are certain variables that play into the numbers, and most of them are very simple lifestyle elements.  For example, what did I just eat?  Did I work out today, and if so, how, and at what time, and for what duration and intensity?  When was the last time that I changed my set?  Are there bubbles in the cord?  Am I unusually stressed out?  Nervous?  Getting sick?  Usually, by the time that I get to the bottom of the list, I have identified the one variable that is causing me problems.