I recently flew for the first time since being diabetic. I flew to Disney last Saturday morning, will be flying and returning again tomorrow morning. After reading the above articles I opted to remove my insulin pump during my one hour flight and risk going high instead of low.
The above articles proved to be true by my experiment.
While on runway I removed my pump. During ascent into the air I witnessed my pump deliver close to about an entire unit of insulin WITHOUT me manually delivering anything and with my pump telling me I still had the same number of units in the cartridge as I did before take off.
I spoke with Medtronic multiple times before my flight to gain access to their experience with this and they all seemed clueless and denied of hearing of any issues such as this.
My entire flight was one hour five minutes long.
While cruising my pump seemed to be working normally.
During descent my insulin pump began sucking insulin backwards creating huge air bubbles in the tubing.
During this flight I went from a blood glucose of 70 to 248.
This was much less risky to me than the other option. I require very small insulin doses and have absolutely NEVER taken an entire unit of insulin at one time. If I had opted to leave my pump on as Medtronic instructed I would have experienced a severe hypoglycemic reaction.
Just wanted to get the word out there to my fellow diabetics as this has never been mentioned before and even Medtronic seems to be unaware of it. I will be calling them personally later today and reporting my experience.
Now on to do it all over again tomorrow morning. Very nervous about how quickly my blood sugar went up last time and it happening again tomorrow. Does this mean I am very insulin dependent or is this a normal type 1 reaction? Do you guys think I should maybe bolus even 0.1u so I do not rise so rapidly?
WATCH YOUR INSULIN PUMPS DURING FLIGHT!!!
Happy Friday!
-Jenn
Thanks for the very well researched update. Clearly this is something to be aware of. However, it seems there are a couple of variables at play here that make this more of a risk for some than for others. The data seems to suggest that there is greater risk with a tubed pump than a patch pump (i.e., Omnipod). I can validate this from my own experience, as I'm on planes almost every week and I've never experienced this with my Omnipod. The other factor is insulin sensitivity, which is clearly high in your case, and probably also in children simply because of size and weight. As a fully grown adult male with average insulin sensitivity, a 1 unit "surprise" would only affect me by about 30pts and not put me in a life threatening situation.
Regardless, this is an important post and thank you for highlighting this risk.
Interesting studies for sure, and the logic appears to be quite straightforward.
My own experience has not followed this, although I do not fly very often (1 - 2x/year). I also test pretty frequently, so maybe it has happened and I just ate glucose tabs for over-delivery (or a lower tempy basal rate) and corrected for the under-delivery.
In your case, could you have experienced some additional high BG due to your stress level being raised?
Thank you for bringing this to my attention. I guess I wasn’t monitoring diabetes news as closely in 2011 when this study was published. I worked for a major commercial airline for 25 years and am aware of the pressure changes that occur during flight.
I’ve used insulin pumps non-stop for the last 28 years and have probably average about six flights per year. Since I’ve averaged about 35-60 units per day during that time, I probably attributed any BG changes to other travel related events.
You’ve raised an important point that insulin sensitive people like yourself and parents of small children need to monitor closely. For people like me, it doesn’t seem to have a large effect. I watch my BGs closely, especially when travelling, and I always carry quickly acting sources of glucose.
The bigger lesson for me is in the case of an emergency decompresssion, a relatively rare event. I guess i never thought that one through and it would have caught me unaware until your post.
Thank you! I've been wearing a pump for more than 8 years and didn't know about this! I take about 30 units/day and travel by plane several times a year. Wearing my CGMS I thought my lows on planes was a CGMS problem in flight (and high after landing), but now I know it's a pump delivery problem. I plan to disconnect after getting on the plane before takeoff, and after taking a small .1 or .2 Unit bolus to carry me, until I reconnect after "reaching cruising altitude". Also good idea to check and clear the line from bubbles after landing!
This is really valuable information. Like Terry, I used to work for a major airline, but I wasn't diabetic then so issues like this didn't arise. (Never mind how long ago!)
Being on MDI, I am not touched personally by this -- yet. But that could change one day and this is terribly important to be aware of. Thanks for doing the homework on this.
What would happen during an emergency decompression??? Would it cause the pump to deliver a bunch of insulin?? That would make that situation 10x scarier than it otherwise would be!
I fly several times a year but, like you, I use 40-70u a day (depending on hormones and other factors) and attributed BG changes to running around airports and the stress of travel.
But you were watching your pump with the tube disconnected from your body, correct? If the tube is inserted into the infusion set and connected to your body, wouldn't that affect the ability of the air pressure to interfere with the pump workings? I'm certainly not a scientist of any type and I don't pump, so I don't know about their mechanics, but that was my first thought.
That's what I wondered. Also since the reservoir amount stayed the same how could one know the delivery amount of "about an entire unit"? And then the " sucking insulin backwards" blows my mind. This should never happen for any reason ever. I hope a new pump is on the way.
Shadow Dragon said: "If the tube is inserted into the infusion set and connected to your body, wouldn't that affect the ability of the air pressure to interfere with the pump workings?"
Absolutely right. Which is why this doesn't happen with the OmniPod or when a tubed pump remains connected. It's simple physics.
This really intrigues me so I did a bit of googling. Here's a link to a study that was done. The conclusion from the authors:
CONCLUSIONS Atmospheric pressure reduction causes predictable, unintended insulin delivery in pumps by bubble formation and expansion of existing bubbles.
A 10-year-old girl with well-controlled type 1 diabetes managed with insulin pump therapy developed recurrent hypoglycemia 60 to 90 min after commencing commercial air travel. Upon direct inquiry, we are now aware of 50 children and adults using insulin pumps who experience this phenomenon.
In 1994, Aanderud et al. (1) demonstrated that insulin pumps delivered “more insulin than the set rate during decompression.” At sea level, the ambient pressure is 760 mmHg (1 atmosphere). When commercial planes ascend to 40,000 feet, the cabin pressure decreases by 200 mmHg to 560 mmHg (cabin pressure equivalent of 8,000 feet) (2). The objective of this study was to investigate the effects of pressure changes during airplane flight on insulin pump delivery.
Jenn posted this link in her discussion along with two other studies. Knowing this is possible just means (for us who fly a lot) to test often and be prepared. The delivering more insulin is NOT okay of course, but the sucking it backwards is a new one. MM has tested their pumps on flights. If a pump does this, it needs to be reported and replaced.
This is interesting food for thought regarding the physics and whether or not the pump being connected matters, but unless you are extremely insulin sensitive its probably not worth worrying about in my opinion-- considering there are thousands of people flying on airplanes with insulin pumps at any given moment and I’m not aware of an epidemic of them keeping over dead mid flight;)
Hi, it’s not to do with the pump at all, and replacing the pump will do nothing to help this issue. It’s just a reversal of the process that caused the overdelivery - that is as pressure increases as you go down, the bubbles that formed and existing ones that grew on the way up get re-dissolved and shrink respectively. I was on a flight today and tested with a cartridge and infusion set (not inside a pump) and on the way down it sucked back in 4" bubble. this was with 100U in the cartridge, and it is dependent on how much insulin you have in the cartridge, if you have a full 300U cartridge you could be getting several extra units on the way up, and on the way down, it will suck blood into the line which can wreck the site (cause occlusions etc).
Hi. Okay, you’re issues with flying with your pump are quite different than mine. So as long as you know then you can avoid the trouble. My pump has never sucked my blood into the line, thank goodness.
Might be the type of pump. We use an Animas Vibe, which has a rigid cartridge reservoir. When bubbles are formed in there and expand, there’s no-where to go but down the line and that pushes whatever is in the line out. I’m starting to think that some other pumps (e.g. t:slim) may be immune to this if they don’t have a rigid cartridge / plunger type design.