ESPE Abstracts

Introduction: Congenital Hyperinsulinism (CHI) is a rare disease of hypoglycaemia due to excess insulin production. Patients with both focal and diffuse forms of CHI may have severe hypoglycaemia not responsive to medical therapies. Such patients require lesionectomy or subtotal pancreatectomy with a corresponding necessity for enhanced glycaemic monitoring during the peri-operative period. Subcutaneous Continuous Glucose Monitoring (CGM) provides real-time high-frequency glucose readings in contrast to infrequent fingerpick blood glucose (BG) testing, although accuracy of detection of true hypoglycaemia remains circumspect. CGM has reported benefit for CHI patients in the outpatient setting but there is no data of the use and utility in patients undergoing surgery. We aimed to describe the use of CGM in one highly specialised centre through questionnaire survey of professionals and assessment of CGM accuracy in the peri-operative period.

Methods: Dexcom G6 CGM was used during pancreatic surgery for 10 patients over a 2-year period. Professional (anaesthetist, surgeon, endocrinologist, and specialist nurse) perception of CGM was assessed by 1-5 Likert scale and open questions in a questionnaire. Accuracy of CGM was tested on the Hypoglycaemia Error Grid.

Results: Seventeen professionals (5 Anaesthetists, 2 Surgeons, 7 Endocrinologists, 3 Specialist Nurses) completed questionnaires. All but one respondent found CGM very helpful or extremely helpful in the peri-operative period. A single endocrinologist was neutral on the utility of CGM in this setting due to concerns of device accuracy. Anaesthetists reported enhanced patient safety in avoiding hypo/hyperglycaemia with CGM, while surgeons commented on its use, in conjunction with histopathology, to identify successful surgery. Endocrinologists/specialist nurses highlighted that CGM reduced the frequency of fingerpicks and supported glucose reduction post-operatively. Peri-operative CGM glucose levels were significantly higher than those normally found outside the peri-operative period (mean (SD) 11.4mmol/L (4.1) vs 6.4mmol/L (2.2)). Accuracy was comparable to the outpatient setting with mean absolute difference (MAD) of 1.4mmol/L. Due to the rarity of hypoglycaemia in the peri-operative setting, and the high tolerance of CGM error at hyperglycaemic levels on the Hypoglycaemia Error Grid, 98% of values were classed as clinically safe.

Conclusion: In spite of low point accuracy, the low impact of CGM error at normal/high glucose levels ensures the safety of CGM as a surgical adjunct. Professional consensus is that CGM use in the peri-operative period has utility in the management of patients undergoing pancreatic surgery. CGM highlights surgical hyperglycaemia, prompting timely reductions in high concentration glucose infusions.