The Flight Rules of Diabetes

At NASA we operate our spacecraft using something called "Flight Rules". There are volumes and volumes of such rules, providing guidance on everything from the length of a spacewalk to how to depart the space station in case of emergency. We use these rules to build our timelines, streamline real-time communication, and assess risk.

At its core, a 'flight rule' is a decision planned in advance.

Some of my diabetes flight rules

As I was driving home from a late shift a few weeks ago I thought about how so many parts of my life have their own "flight rules" -- including diabetes. Sure there are the concrete rules:

• Change your site every 3 days

• Keep your insulin in a specific temperature range

• Treat a low blood sugar with 15 grams of carbohydrates

But there are so many others!

At NASA we try to use very precise language to define thresholds, some things are "required" to mitigate a hazard while other things are just "highly desired" or even less stringently, "consideration should be given". I started lumping my diabetes flight rules in similar buckets:

Required:

• Insulin pump charge level must remain above 10%

• Carry enough diabetes equipment to be one-fault-tolerant

• Always carry fast-acting glucose

Highly Desired:

• Charging cords available in high use areas

• Placement of insulin pump and CGM sites in approved locations

• Bolus 30 minutes before eating a meal

Consideration should be given:

• Wear a medical ID bracelet

• Change pump settings for extended duration activity

• Use of an alcohol swab (!)

• Change lancet before every BG check (ha)

Obviously, these buckets and rules will be different for everyone, all based on their individual risk acceptance comfortability, age, access, experience, and a million other factors. Heck, individually we may even jostle rules between difference buckets, which leads me to...

Changing the rules

The other notable property of flight rules is they are not static. There is a detailed process to update them based on new information, new analysis, a change in hardware or software, a change in configuration, and flight experience. As people with diabetes, we know this all too well. Got a new pump? Update the diabetes flight rules. Pregnant? Update the diabetes flight rules. Changing insulin types? Update the diabetes flight rules. Going on vacation? Update the diabetes flight rules. We are constantly making tiny tweaks, zeroing in on the best rhythm and constraints for our specific diabetes situation.

Waiving a flight rule

At NASA someone called the "Flight Director" has the ultimate authority to waive any given flight rule. Why would you do such a thing anyway? Well, in space travel, as in diabetes, there are situations or combinations of failures that we just can't predict. And so, we have mission control staffed with humans instead of just computers. Sometimes it takes engineering judgment, not algorithms, to make the best decision for a particular scenario. You can probably see where this is going...

As people living with type 1 diabetes (or caregivers), we are our own diabetes flight directors. We make decisions based on inputs, data, and projections. We understand the strengths and limitations of our "team" (CGM, insulin pump, glucose meter, A1c, etc), and build cases almost every day to waive flight rules in pursuit of our own safety.

What are some of your diabetes flight rules?