Navigating Airport Security with an Insulin Pump and/or Sensor

N ew technologies are constantly being developed for diabetes management. It is impossible to know in advance all of the possible ramifications relating to patient care and safety. A recent report ¹ and editorial ² raised concern about the effects of pressure changes during air travel on insulin delivery from an insulin pump. A similar situation may exist with current airport safety screening and insulin pumps and continuous glucose monitoring (CGM) devices. There is a potential for problems, and people need to be made aware of currently recommended practices. With all of the changes a person makes with airplane travel (including food intake, stress, and exercise), along with the potential for technological difficulties, more frequent self-monitoring of blood glucose levels remains highly recommended.

We recently encountered a 16-year-old patient with type 1 diabetes from our Center who experienced potential insulin pump malfunction after being forced to walk through a full-body scanner by the Transportation Security Administration (TSA) screeners. ³ The patient presented to the TSA screeners with a doctor's note detailing the medical function of her insulin pump and the potential damage a pump can sustain from passing through a full-body scanner, as well as requesting that a pat-down be done instead. ³ This request was fully in accord with the TSA's own guidelines, which provide the following instructions to travelers: “If you are concerned or uncomfortable about going through the walk-through metal detector with your insulin pump, notify the Security Officer that you are wearing an insulin pump and would like a full-body pat-down and a visual inspection of your pump instead.” ⁴ Despite being well prepared for the demands of traveling with a pump and other diabetes supplies and making a request that is officially endorsed as legitimate by the TSA, the patient was told to take the pump through the full-body scanner, and it may have suffered damage as a result. Although the damage in this case was apparently hypothetical, the manufacturer took the safest approach. Upon being contacted by the family, Animas (a Johnson and Johnson Company, West Chester, PA), the manufacturer of the insulin pump, advised her to disconnect from the pump, as the company was not able to guarantee whether or not damage had occurred. ³

When an insulin pump or CGM device is passed through a full-body scanner, X-ray scanner, or other imaging equipment, there is a risk the motor may experience electromagnetic malfunctioning. There is scant published research on the impact of imaging technology on pumps and CGM devices, although manufacturers have conducted numerous related tests on their products and offer advice as to what kinds of equipment may cause interference. The Airport Security Guidelines from Medtronic (Northridge, CA) state that their CGM devices and pumps can safely pass through metal detectors but that the pump and CGM device (both sensor and transmitter) should be removed if going through an airport body scanner (Table 1). ⁵ The metal detector is of low magnetic energy and thus will not cause interference with insulin pumps or CGM devices. In contrast, the body scanner is a low-energy X-ray device producing approximately 3.8 microrems per screening. Medtronic also provides patients with airport information cards, which clearly state, “To avoid removing your devices, you may request an alternative screening process. If you choose to go through a full body scanner, you must remove your insulin pump and CGM [device] (sensor and transmitter). Do not send your devices through the X-ray machine as an alternative.” ⁶ Advising patients not only to be aware of the potential dangers of X-ray and body scanners, but also to carry an airport information card while traveling, may make it easier for them to get their request granted by TSA screeners. Medtronic also lists an equipment interference chart on its Web site, detailing which of its devices should be kept away from various sources of interference. These include X-rays, magnetic resonance imaging machines, positron emission tomography scanners, computed tomography scanners, and airport body scanners. ⁷ Animas recommends that patients not expose their pumps to X-ray equipment and instead request a hand-wand inspection. ⁸ The only pump company that does not advise users to avoid any machines is OmniPod^® (Insulet Corp., Bedford, MA), whose system utilizes shape-memory alloy wire technology, as opposed to a direct current motor, thus rendering it theoretically safe from electromagnetic malfunctioning risk. ⁹

Another novel problem stemming from improved technologies involves the effects of hypobaric pressure conditions on insulin delivery. King et al. ¹ found that hypobaric conditions led to an average increased insulin delivery of 0.623% of the cartridge volume. Although these results were predictable (decreased pressure leads to an increase in bubble formation, consistent with Henry's Law of gas solubility, as well as an increase in size of preexisting bubbles, consistent with Boyle's Law), it is a new challenge to make sure patients are adequately informed of a possible problem before traveling. A separate study, conducted by Adolfsson et al., ¹⁰ found that the mean absolute relative difference in CGM readings was lower during hyperbaric than hypobaric conditions, and sensor sensitivity was slightly decreased during hypobaric conditions. Although insulin pump and CGM technology generally makes diabetes management easier, many patients may not be aware of potential problems, such as the effects of hypobaric and hyperbaric pressure or of imaging equipment, on insulin delivery and CGM device functioning. It should also be realized that changes in insulin delivery may be more critical for younger children who may be more sensitive to insulin and receiving a lower total daily insulin dose.

We currently provide all patients with a standard travel letter, ¹¹ which details the medical supplies travelers must keep on their person during flights and can be presented to security officials in the event they have questions during the screening process. Among other things, the letter states, “This patient's insulin infusion pump should not be exposed to magnetic X-ray equipment, including a full body scanner. Please ensure that this device be hand-checked by TSA personnel.” ¹¹ It is probable that on any given day, large numbers of travelers subject their insulin pumps and/or CGM devices to X-ray and full-body machines, and some may unknowingly experience mild (or worse) malfunctioning as a result. More research is needed to better evaluate the frequency of problems and the type of problems most likely (e.g., increased vs. decreased insulin delivery from an insulin pump). Awareness is thus paramount, and it is the responsibility of diabetes care providers to increase this awareness in their patients.