Unintended insulin delivery using Omnipod DASH during a high-altitude flight
- 1 Dermatology, Campbell University School of Osteopathic Medicine, Buies Creek, North Carolina, USA
- 2 Dermatology, Sampson Regional Medical Center, Clinton, North Carolina, USA
- 3 Endocrinology, New Hanover Regional Medical Center, Wilmington, North Carolina, USA
- Correspondence to Dr Jonathan Crane; lcrane2384@msn.com
Abstract
Insulin pumps are an important tool in the management of type I diabetes mellitus. Omnipod DASH is a tubeless insulin pump that delivers insulin through customisable basal rate and bolus amounts. There is no data available to date on how this insulin pump delivery system is influenced by changes in atmospheric pressure during flight at high altitudes. We report a case of a 55-year-old woman who developed symptomatic hypoglycaemia while using this pump during flight in a non-pressurised cabin. This report demonstrates the risk of insulin pump therapy at high altitudes. Flight emergencies involving rapid depressurisation may lead to catastrophic hypoglycaemia. Caution should be exercised when using insulin pump therapy during flights and manual insulin delivery should be considered.
Background
Approximately 27 million Americans are diagnosed with diabetes mellitus (DM). Among diabetic adults, 3 million started on insulin therapy within 1 year of diagnosis.1 Insulin pump represents an important tool in management of type I DM. Multiple studies reported clinically meaningful improvement in glycaemic control for patients initiating insulin pump therapy compared with treatment with multiple daily injections.2
Omnipod DASH Insulin Management System is a tubeless insulin pump that holds up to 200 units of insulin and delivers insulin through customisable basal rate and bolus amounts. It builds on utilisation of Bluetooth wireless technology to enable communication between disposable infusion pump (Pod) and personal diabetes manager.2
Hypoglycaemia is a frequent and potentially serious complication of insulin therapy, with possible sequelae including seizure, coma, and death. Atmospheric pressure variation affected pump insulin delivery.3 New model, Omnipod DASH insulin pump is waterproof certified. However, there is no clear data available to date on how this insulin pump delivery system is influenced by changes in atmospheric pressure during the flight at high altitudes.
Case presentation
An early 50s woman with DM type 1 developed severe hypoglycaemia while using the Omnipod DASH system in conjunction with Dexcom G6 continuous glucose monitoring system (CGMS). On flight 1, level of glucose decreased from 160 to 39 mg/dL at a recorded altitude ranging from 32 to 8000 ft (figure 1A). On flight 2, level of glucose decreased from 130 to 51 mg/dL at 2500 to 7000 ft (figure 1B). Based on CGMS data, level of glucose began decreasing approximately in 15 min after reaching desirable cruising altitude at 7000–8000 ft and reached hypoglycaemic level, less than 70 mg/dL, within 40 min during both flights (figure 1A,B). During hypoglycaemia episodes the patient experienced fatigue, dizziness, diaphoresis and confusion. She consumed 65 g and 40 g of carbohydrates in the form of a glucose Gel on flight 1 and 2, respectively. However, hypoglycaemia persisted for the remainder of both flights and improved only after landing.
Flight altitude (blue) and serum glucose (red) displayed as a function of time on flight 1 on 1 August 2020 (A) and flight 2 on 2 August 2020 (B). A total of 65 and 40 g sugar (green) was consumed during flight 1 (A) and flight 2 (B), respectively.
Outcome and follow-up
Hypoglycaemia resolved once the aircraft landed and did not recur. The Omnipod DASH was sent back to the manufacturer.
Discussion
We report a case of a 55-year-old female who developed symptomatic hypoglycaemia while using the Omnipod DASH insulin pump with Dexcom G6 CGMS during the flight in a non-pressurised cabin aircraft at 7000–8000 ft above the sea level. Based on CGMS data, the glucose level started to decrease approximately 15 min after reaching desirable cruising altitude and persisted until landing despite carbohydrate consumption.
Previous studies demonstrated that reduction in atmospheric pressure causes predictable unintended insulin delivery. According to the Boyle low, volume of a gas inversely proportional to the pressure of the system; therefore, as atmospheric pressure decreases with higher altitude, the volume of the air bubbles increases in the insulin cartridge leading to increased insulin release.3 Moreover, Bertuzzi et al demonstrated an unintended insulin delivery occurred when pressure decreased by 0.3 ATA, which corresponds to the changes in the atmospheric pressure during a flight take off, from 1,013 hPa at sea level to 778 hPa at about 8000 ft. This phenomenon was observed in different insulin pumps including Omnipod. Furthermore, in the case of the Omnipod pump, the use of proprietary technology prevents air bubble trapping during Pod filling. However, the technology may not be effective if the Pod is partially filled.4
The Omnipod manufacturer ensures the safety of using the pump during flight in atmospheric pressure as low as 700 hPa, which is lower than the typical pressure in aeroplane cabins, and up to 10 000 ft altitude.2 Conversely, our case suggested unintended insulin delivery may occur at higher ambient pressure and lower altitude, as the maximum recorded altitude was 8000 ft (752 hPa) and 7000 ft (782 hPa) on flight 1 and 2. Commercial flights typically reach 30 000–40 000 ft, at which atmospheric pressure is 200–300 hPa.5 However, cabin pressure in commercial airlines is generally controlled to the atmospheric pressure experienced at 6000–8000 ft. Our patient’s flight was in non-pressurised aircraft; therefore, the cabin pressure was equivalent to atmospheric pressure at given flight altitude. Flight emergencies involving rapid depressurisation may lead to catastrophic hypoglycaemia as the sudden, drastic pressure change may cause a large amount of insulin delivery.5
Learning points
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Insulin pump malfunction can occur at high altitudes leading to inappropriate delivery of insulin.
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If hypoglycaemia occurs at high altitude, insulin pump malfunction should be considered and disconnected.
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For insulin dependent diabetics, glucose should be carefully monitored while in-flight.
Ethics statements
Patient consent for publication
Footnotes
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Contributors MS participated in this case, helped review literature on this topic, and helped write and edit the final manuscript. YH helped review literature on the topic and helped write the final manuscript. MP participated in the case and helped write the final manuscript. JC participated in the case and helped write and edit the final manuscript. He is the corresponding author.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.
References
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