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Technical Pitfalls of Insulin Pump Clock

Oct 17, 2012

Special guest blog from Saleh Aldasouqi, MD, FACE, ECNU, Associate Professor of Medicine, Michigan State University College of Human Medicine, East Lansing, and Director of Sparrow Diabetes Center, Lansing, Michigan

My team at Michigan State University and Sparrow Diabetes Center presented a poster at the 2012 AADE Annual Meeting that received considerable attention.  A pump manufacturer recently circulated a warning to users regarding a “glitch” in its software that didn’t recognize the 2012 leap day (February 29th). This could cause a basal insulin delivery or a recommended bolus amount that is incorrect for the actual time of day and could result in unexpected high or low blood sugars.

We recently encountered a similar issue related to a pump’s clock set up. An 18-year old international college student with type 1 diabetes had been using an insulin pump, which she started in her native country (where no seasonal daylight savings time changes occur). When we saw her in clinic this summer, her pump’s clock was one hour late because she didn’t realize the need to manually change the clock in the spring. Fortunately, no significant harm resulted from the incorrect setting, given the trivial time difference. However, while the daylight savings time change may not cause serious harm with just one hour difference, we do foresee a more serious problem with regards to 12-hour (AM, PM) versus 24-hour formatting. For example, if the pump’s clock is not set up correctly (e.g., PM instead of AM), this may result in incorrect insulin delivery; the patient may then receive the PM basal rate (usually higher) at midnight, potentially causing nocturnal hypoglycemia. Therefore, in order to avoid this human error, it is safer to use the 24-hour format.

It’s important that patients set up their pumps’ time and date correctly at all times. But insulin pump manufacturers can also help prevent such technical pitfalls. They constantly educate patients about all safety issues related to insulin pumps, including time and date set up, which is helpful. However, relevant technical improvements are desirable, such as equipping insulin pumps with built-in automatic time and date adjustment, or even equipping pumps with GPS connectivity which would guarantee that pumps clocks automatically adjust when patients travel across time zones.

However, until all pumps are equipped with automatic time and date adjustment, I recommend diabetes educators to inform their patients about adjustments for seasonal time and date changes,  to pay attention to current date and time settings of their pumps, and to constantly verify that the pump clocks are set up correctly at all times.


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  1. Nov 01, 2012

    This is an informative article on an important topic. When we reviewed the iBG Star we asked similar questions about traveling across time zones and would the meter make the adjustments. They were going to look into that feature. Thanks, Lisa
  2. Oct 23, 2012

    A nice review and reminder! Much appreciated-- Kellie
  3. Oct 20, 2012

    Very important reminder during this time of year!
  4. Oct 18, 2012

    Your blog provided excellent reminders for diabetes educators. The use of the 24 hour clock might be a hard sell to patients, but given the benefits your outlined, you have equipped us to better encourage the use of this feature. I can't wait for the GPS feature! Thank you.
  5. Oct 18, 2012

    very practical useful info. Thank you.
  6. Oct 17, 2012

    Thank you for this very timely information as our clocks are about to change again as the end of daylight savings time is near. Hopefully everyone out there will remind their patients to check the clocks not only on their pumps but their meters too. Here is the Daylight Saving Time Schedule for the USA 2012 – 2015, as prescribed in The Energy Policy Act of 2005. (remember the time changes at 2 am local time.) 2012 11 March 2012 4 November 2012 2013 10 March 2013 3 November 2013 2014 9 March 2014 2 November 2014 2015 8 March 2015 1 November 2015

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