Effects of atmospheric pressure change during flight on insulin pump delivery and glycaemic control of pilots with insulin-treated diabetes: an in vitro simulation and a retrospective observational real-world study
Authors' conclusion
Ambient pressure reduction during simulated flights results in bubble formation and expansion within insulin cartridges. This causes unintended delivery of small insulin doses independent of pre-determined delivery rates and represents the maximum amount of insulin that could be delivered and retracted. However, in vivo, pilots using CSII in-flight did not experience a fall in blood glucose or episodes of hypoglycaemia during these atmospheric pressure changes and the use of insulin pumps can be endorsed in view of their clinical benefits.
Study context
- Population
- Commercial and private pilots with insulin-treated diabetes granted a medical certificate to fly within the European Union Aviation Safety Agency approved protocol; in vitro insulin pumps in hypobaric chamber de-pressurised to 550 mmHg
- Exposure
- Continuous subcutaneous insulin infusion (CSII) vs multiple daily injections (MDI) in pilots with insulin-treated diabetes; insulin pump delivery under simulated flight pressure changes
- CSIIn = 7
- Outcome
- Insulin delivery vs ground-level performance (in vitro, full cartridges)
Methodological detailshypobaric chamber simulation, 7.5-year retrospective cohort, real-world observational
- Hypobaric chamber simulation
- 7.5-year retrospective cohort
- Real-world observational
Main finding
As reported in the abstract
Over-delivery during 20 min ascent
0.60 U
Under-delivery during descent
0.51 U
Excess insulin delivered during emergency rapid decompression
5.6 U
Observational data: associations, not effects.
Further findings
Insulin delivery during simulated flight (in vitro, hypobaric chamber 550 mmHg), full cartridges vs ground-level performance
U
- Over-delivered during 20 min ascent
- 0.60
- Under-delivered during descent
- 0.51
- Excess insulin delivered during emergency rapid decompression
- 5.6
- In vitro simulation
In-flight self-monitored blood glucose (SMBG) in pilots using CSII
- Pilots using CSII
- 7
- SMBG values recorded during 2345 h of flying across 1081 flights
- 4656
- Values outside acceptable safe range (5.0-15.0 mmol/l [90-270 mg/dl])
- 33 (0.7%)
- No clinically significant fall in median SMBG after aircraft ascent
- Retrospective cohort, 7.5 years
CSII vs MDI pilots: SMBG values
- Values within acceptable range, CSII vs MDI
- 99.3% vs 97.5%
- Values in low red range, CSII vs MDI
- 0.02% vs 0.1%
- In-flight out-of-range values, CSII vs MDI
- 0.2% vs 1.3%
- CSII pilots maintained stricter glycaemic control during flight
Safety
In-flight hypoglycaemia (<4.0 mmol/l [<72 mg/dl]) in pilots using CSII
- No in-flight SMBG values within the hypoglycaemic range (<4.0 mmol/l [<72 mg/dl])
Original publication
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