Perioperative Care of Patients Using Wearable Diabetes Devices

The increasing prevalence of diabetes mellitus has been accompanied by a rapid expansion in wearable continuous glucose monitoring (CGM) devices and insulin pumps. Systems combining these components in a "closed loop," where interstitial glucose measurement guides automated insulin delivery (AID, or closed loop) based on sophisticated algorithms, are increasingly common. While these devices' efficacy in achieving near-normoglycemia is contributing to increasing usage among patients with diabetes, the management of these patients in operative and procedural environments remains understudied with limited published guidance available, particularly regarding AID systems. With their growing prevalence, practical management advice is needed for their utilization, or for the rational temporary substitution of alternative diabetes monitoring and treatments, during surgical care. CGM devices monitor interstitial glucose in real time; however, there are potential limitations to use and accuracy in the perioperative period, and, at the present time, their use should not replace regular point-of-care glucose monitoring. Avoiding perioperative removal of CGMs when possible is important, as removal of these prescribed devices can result in prolonged interruptions in CGM-informed treatments during and after procedures, particularly AID system use. Standalone insulin pumps provide continuous subcutaneous insulin delivery without automated adjustments for glucose concentrations and can be continued during some procedures. The safe intraoperative use of AID devices in their hybrid closed-loop mode (AID mode) requires the CGM component of the system to continue to communicate valid blood glucose data, and thus introduces the additional need to ensure this portion of the system is functioning appropriately to enable intraprocedural use. AID devices revert to non-AID insulin therapy modes when paired CGMs are disconnected or when the closed-loop mode is intentionally disabled. For patients using insulin pumps, we describe procedural factors that may compromise CGM, insulin pump, and AID use, necessitating a proactive transition to an alternative insulin regimen. Procedure duration and invasiveness is an important factor as longer procedures increase the risk of stress hyperglycemia, tissue malperfusion, and device malfunction. Whether insulin pumps should be continued through procedures, or substituted by alternative insulin delivery methods, is a complex decision that requires all parties to understand potential risks and contingency plans relating to patient and procedural factors. Currently available CGMs and insulin pumps are reviewed, and practical recommendations for safe glycemic management during the phases of perioperative care are provided.