SAT-534 - Where Precision Meets Consequence: A Basal Decimal Slip Exposing the Human Side of AID Technology

Introduction: Automated insulin delivery systems improve glycemic outcomes in diabetes, but errors in pump programming can occur inadvertently and lead to poor glycemic control.

Case Description: A 33-year-old female with type 1 DM presented with worsening glycemic control after transitioning from a Tandem pump with Control-IQ to the Omnipod 5, over 1 year ago. She had previously managed diabetes effectively with the OmniPod 5. However, recent A1c was 9.8% after a respiratory illness. Her Pump download revealed that total daily Insulin dose had increased during the illness, and she was having post-prandial hyperglycemia. These spikes often triggered ‘Automated Delivery Restriction’ alarm, forcing her into manual mode. When this happened after midnight, she had significant glucose spikes that even persisted most of the day. We noticed that during pump transition, her programmed basal rate from 12am to 5am was entered as 0.05 unit/hr instead of actual 0.5 unit/hr, a ten-fold reduction. This was never noticed during follow up because Omnipod 5 automode algorithm does not take programmed basal rates into account and it was only obvious after illness when total daily dose increased substantially leading to a cycle of ‘Automated Delivery Restriction’ alarms, automode kickout, manual mode, and significant nocturnal hyperglycemia. This exacerbated when she occasionally omitted late evening mealtime boluses. She often remained in Manual Mode, unaware that she needed to actively switch back to automation. In manual mode, the system delivered the erroneously low basal of 0.05 U/hr, resulting in prolonged nocturnal hyperglycemia. Over five hours, she was receiving only 0.25 units instead of 2.5 units, contributing to elevated A1c. No mechanical pod failures or insulin absorption issues were identified. Correction doses were consistent because basal insulin was essentially absent overnight.

Conclusion: This case highlights how small programming errors during pump transitions can cause dangerous issues with glycemic control that are not obvious until an unexpected increase in total daily dose occurs. In Omnipod 5, 'Automated Delivery Restriction' is a safety alarm that is triggered when the pump has been delivering maximum insulin or suspending insulin for too long in response to persistently extreme glucose levels. Per Omnipod 5 design, clearing an Automated Delivery Restriction alarm transitions the system to Automated Mode: Limited, and shortly thereafter to Manual Mode, where insulin delivery relies entirely on the user-programmed basal rates. To re-enter full automation, the user must manually reactivate 'Automated Mode' after waiting at least five minutes. This highlights the importance of meticulous review of pump settings during device changes and reinforcement of user education regarding insulin pump systems.

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