Researchers in a new study say diabetics who use insulin pumps should consider disconnecting them during take-off on airplanes to avoid changes to their blood sugar level, which could result in unintended consequences to their metabolism.
According to lead researcher Dr. Ka Siu Fan with the University of Surrey in the United Kingdom, air bubbles can form inside insulin cartridges during depressurization in a plane’s cabin at takeoff, which can affect how much insulin is delivered.
“To prevent any unintended metabolic consequences, we recommend that individuals who use insulin pumps consider temporarily disconnecting their pumps before take-off and removing air bubbles before reconnecting it at cruising altitude,” he cautioned.
The bubbles can pull excess insulin out of the cartridges as cabin pressure drops, resulting in a higher-than-usual insulin dosage, which can result in Hypoglycemia or low blood sugar, according to a Sept. 8 news release by researchers from the Medical University of Graz, John Hunter Hospital, UZ Leuven, Royal Surrey County Hospital, and University of Surrey.
The findings were revealed on Sunday at the annual European Association for the Study of Diabetes meeting in Madrid.
“Individuals who use insulin pumps should be aware of the potential impact of changes in the cabin air pressure on insulin delivery,” Dr. Fan said in the same news release.
Preventative measures include disconnecting such pumps during take-off and removing any air bubbles that may have formed, and reconnecting after the plane has reached its cruising altitude, according to Fan.
During the study researchers tested 26 different insulin pumps which were placed in Europe’s largest hypobaric chamber, which was used to simulate the air pressure during a normal commercial flight, according to the news release.
The pumps over-delivered insulin during a simulated 20-minute ascent—which can cause a drop in blood sugar levels—and under-delivered during a simulated 20-minute descent, as air in the cabin re-pressurized.
The chamber was de-pressurized to 550 mmHg during ascent, maintained for 30 minutes to mimic a cruising altitude of 8,000 feet, and re-pressurized to 750 mmHg during descent to the ground.
During the simulation, insulin delivery was set at a rate of 0.6 units per hour to represent the typical rate for adults and paediatric practice, according to the study.
While insulin was over-delivered during ascent, it was also under-delivered during descent.
According to Fan, as the plane re-pressurizes on the descent, the same air bubbles that formed may then dissolve, sucking insulin back into the pump, which reduces how much is delivered. Insulin was delivered at a rate of 0.51 units per hour on descent, the findings showed.
Fan said the potential for such effects depends on several factors, including one’s sensitivity to insulin, what one eats, and how much sugar one consumes.
“Whether these abnormalities in insulin delivery during flights cause clinical effects will depend on several factors, including an individual’s insulin sensitivity, food intake, and glycaemic control,” he said.
Researchers said neither was cause for concern, but the dangers posed by too much insulin are greater than those from not enough.
The study also measured insulin delivery during rapid decompression, which, although rare, could happen in an emergency, such as when a plane loses its door mid-flight. Findings showed an excess delivery of insulin, which, although dangerous, could be counteracted by eating enough carbohydrates.