Diabetes and insulin pumps during flight

Patients with type 1 diabetes should ensure that their seatbacks are upright, their seatbelts fastened and their insulin pumps disconnected before takeoff, researchers say.

They should also ensure their pump contains only 1.5mL of insulin before flying, remove any air bubbles before reconnecting the pump at cruising altitude, and disconnect again during emergencies.

The advice comes from an Australian study showing that drops in atmospheric pressure can lead pumps to dispense excess insulin – up to 0.6% of the chamber’s contents.

The effect is caused by the formation of new air bubbles in the pump chamber, which displace insulin from the cartridge. Existing bubbles in the insulin can also expand in size by as much as 36%, researchers wrote this week in Diabetes Care (online).

They warned the effect could lead to hypoglycaemia, and made the following recommendations for prospective flyers:

1) Insulin pump cartridges should contain only 1.5mL of insulin when flying.

2) Disconnect the pump before takeoff.

3) At cruising altitude, take the cartridge out of the pump and remove any air bubbles before reconnecting.

4) After the aeroplane lands, disconnect the pump, “prime the line” with two units, then reconnect the pump.

5) Disconnect the insulin pump during in-flight emergencies involving cabin decompression.

The researchers, led by Dr Bruce King of the University of Newcastle, NSW, studied 10 insulin pumps during a commercial Boeing 767-338 flight. They also studied the pumps in a hypobaric chamber mimicking the drop in cabin pressure when flying.

Diabetes Care 2011; online – more info