Perioperative Continuous Glucose Monitoring in Patients Undergoing an Abdominal Surgery

Study Overview
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Brief Summary
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The purpose of this study it to assess whether the continuous glucose monitor system Dexcom G6® can be reliably used for perioperative glucose monitoring in 20 prediabetic or diabetic patients undergoing abdominal surgery in terms of data continuity, accuracy and patient tolerability.

Detailed Description
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The current recommended method for monitoring glucose control is bedside point of care capillary blood glucose testing. A significant limitation for this method is the frequency by which blood glucose testing is typically performed, at most 4-6 times daily. Continuous glucose monitoring (CGM) provides an alternative approach to measure glucose values with the advantage of greater frequency of monitoring as it is measured every few minutes. Whilst CGM use in the outpatient setting is rising and has demonstrated benefits on glycaemic control, the accuracy of these devices perioperatively is less investigated. In this study the sixth-generation factory-calibrated real-time Dexcom G6® system will be used as a CGM and its glucose values perioperatively will be compared to the capillary glucose values which will be measured simultaneously by the Accu-Check Inform II (Roche Diagnostics) point-of-care blood glucose meter. The Investigators aim to assess the feasibility and accuracy of perioperative CGM.

Official Title
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Perioperative Continuous Glucose Monitoring in Patients Undergoing an Abdominal Surgery - an Observational Study

Conditions
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Diabetes Mellitus, Prediabetes

Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Aged ≥18 years Pre-diabetic (HbA1c 5.7-6.5%) or diabetic (regardless of aetiology) Scheduled to have elective abdominal surgery at the University Hospital Bern Surgery duration >2 hours Exclusion criteria: Planned MRI procedure during hospitalization Inability to follow procedures Incapacity to give informed consent Presence of extensive skin abnormalities at the sensor insertion site (upper arm) Known allergic/irritative skin reactions to dressings/adhesives Haematocrit values outside the normal range Patients with immunosuppression defined as neutrophil count <0.5x10^9/L Patients on isolation precautions (contact, droplet, airborne) Pregnancy or breast-feeding

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensor accuracy in the perioperative period | Mean Absolute Relative Difference (MARD) between Dexcom G6 sensor glucose values and capillary blood glucose values measured using the Accu-Check Inform II meter in the perioperative period (%) | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean absolute relative difference between sensor glucose and reference glucose in the preoperative period (%) | Mean absolute relative difference between sensor glucose and reference glucose (for reference values >3.9 and <10.0mmol/l, for reference values ≤3.9mmol/l, for reference values ≥10.0mmol/l) in the preoperative period (%) | 1 week | 
| Mean absolute relative difference between sensor glucose and reference glucose in the postoperative period (%) | Mean absolute relative difference between sensor glucose and reference glucose (for reference values >3.9 and <10.0mmol/l, for reference values ≤3.9mmol/l, for reference values ≥10.0mmol/l) in the postoperative period (%) | 1-2 weeks | 
| Median absolute relative difference between sensor glucose and reference glucose in the preoperative period (%) | Median absolute relative difference between sensor glucose and reference glucose (for reference values >3.9 and <10.0mmol/l, for reference values ≤3.9mmol/l, for reference values ≥10.0mmol/l) in the preoperative period (%) | 1 week | 
| Median absolute relative difference between sensor glucose and reference glucose in the perioperative period (%) | Median absolute relative difference between sensor glucose and reference glucose (for reference values >3.9 and <10.0mmol/l, for reference values ≤3.9mmol/l, for reference values ≥10.0mmol/l) in the perioperative period (%) | 1 day | 
| Median absolute relative difference between sensor glucose and reference glucose in the postoperative period (%) | Median absolute relative difference between sensor glucose and reference glucose (for reference values >3.9 and <10.0mmol/l, for reference values ≤3.9mmol/l, for reference values ≥10.0mmol/l) in the postoperative period (%) | 1-2 weeks | 
| Percentage of sensor measurements in the preoperative period within the limits specified by the International Organization of Standardization (ISO) : 15197:2013 criteria | Proportion of sensor measurements in the preoperative period within ±15% of reference glucose if the reference value is ≥5.6mmol/l and within 0.8mmol/l if the reference values is <5.6mmol/l (%) | 1 week | 
| Percentage of sensor measurements in the perioperative period within the limits specified by the ISO: 15197:2013 criteria | Proportion of sensor measurements in the perioperative period within ±15% of reference glucose if the reference value is ≥5.6mmol/l and within 0.8mmol/l if the reference values is <5.6mmol/l (%) | 1 day | 
| Percentage of sensor measurements in the postoperative period within the limits specified by the ISO: 15197:2013 criteria | Proportion of sensor measurements in the postoperative period within ±15% of reference glucose if the reference value is ≥5.6mmol/l and within 0.8mmol/l if the reference values is <5.6mmol/l (%) | 1-2 weeks | 
| Bias and 95% limits of agreement of sensor glucose compared to reference glucose in the preoperative period | Calculation of bias and 95% limits of agreement of sensor glucose compared to reference glucose in the preoperative period | 1 week | 
| Bias and 95% limits of agreement of sensor glucose compared to reference glucose in the perioperative period | Calculation of bias and 95% limits of agreement of sensor glucose compared to reference glucose in the perioperative period | 1 day | 
| Bias and 95% limits of agreement of sensor glucose compared to reference glucose in the postoperative period | Calculation of bias and 95% limits of agreement of sensor glucose compared to reference glucose in the postoperative period | 1-2 weeks | 
| Clarke error grid analysis in the preoperative period | Proportion of sensor glucose values in Clark's error grid zones (A, B, A+B, C, D, E)in the preoperative period (%) | 1 week | 
| Clarke error grid analysis in the perioperative period | Proportion of sensor glucose values in Clark's error grid zones (A, B, A+B, C, D, E) in the perioperative period (%) | 1 day | 
| Clarke error grid analysis in the postoperative period | Proportion of sensor glucose values in Clark's error grid zones (A, B, A+B, C, D, E) in the postoperative period (%) | 1-2 weeks | 
| Sensor availability in the preoperative period (%) | Proportion of study period with available sensor glucose values in the preoperative period | 1 week | 
| Sensor availability in the perioperative period (%) | Proportion of study period with available sensor glucose values in the perioperative period | 1 day | 
| Sensor availability in the postoperative period (%) | Proportion of study period with available sensor glucose values in the postoperative period | 1-2 weeks | 
| Number of sensor replacement events in the preoperative period | Number of times that the sensor needed to be replaced in the preoperative period | 1 week | 
| Number of sensor replacement events in the perioperative period | Number of times that the sensor needed to be replaced in the perioperative period | 1 day | 
| Number of sensor replacement events in the postoperative period | Number of times that the sensor needed to be replaced in the postoperative period | 1-2 weeks | 
| Number of adverse device effects in the preoperative period | Adverse event related to the use of study devices (e.g. skin irritative and allergic reactions, bleeding) in the preoperative period | 1 week | 
| Number of adverse device effects in the perioperative period | Adverse event related to the use of study devices (e.g. skin irritative and allergic reactions, bleeding) in the perioperative period | 1 day | 
| Number of adverse device effects in the postoperative period | Adverse event related to the use of study devices (e.g. skin irritative and allergic reactions, bleeding) in the postoperative period | 1-2 weeks | 
| Percentage of time in the preoperative period with sensor glucose levels within target range | Proportion of time in the preoperative period with sensor glucose levels between 3.9-10.0mmol/l | 1 week | 
| Percentage of time in the perioperative period with sensor glucose levels within target range | Proportion of time in the perioperative period with sensor glucose levels between 3.9-10.0mmol/l | 1 day | 
| Percentage of time in the postoperative period with sensor glucose levels within target range | Proportion of time in the postoperative period with sensor glucose levels between 3.9-10.0mmol/l | 1-2 weeks | 
| Percentage of time in the preoperative period with sensor glucose levels below target range | Proportion of time in the preoperative period with sensor glucose levels below 3.9mmol/l | 1 week | 
| Percentage of time in the perioperative period with sensor glucose levels below target range | Proportion of time in the perioperative period with sensor glucose levels below 3.9mmol/l | 1 day | 
| Percentage of time in the postoperative period with sensor glucose levels below target range | Proportion of time in the postoperative period with sensor glucose levels below 3.9mmol/l | 1-2 weeks | 
| Percentage of time in the preoperative period with sensor glucose levels above target range | Proportion of time in the preoperative period with sensor glucose levels above 10.0mmol/l | 1 week | 
| Percentage of time in the perioperative period with sensor glucose levels above target range | Proportion of time in the perioperative period with sensor glucose levels above 10.0mmol/l | 1 day | 
| Percentage of time in the postoperative period with sensor glucose levels above target range | Proportion of time in the postoperative period with sensor glucose levels above 10.0mmol/l | 1-2 weeks | 
| Mean sensor glucose value in the preoperative period | Mean value of the sensor glucose levels in the preoperative period | 1 week | 
| Mean sensor glucose value in the perioperative period | Mean value of the sensor glucose levels in the perioperative period | 1 day | 
| Mean sensor glucose value in the postoperative period | Mean value of the sensor glucose levels in the postoperative period | 1-2 weeks | 
| Standard deviation of sensor glucose levels in the preoperative period | Standard Deviation of the sensor glucose levels in the preoperative period | 1 week | 
| Standard deviation of sensor glucose levels in the perioperative period | Standard Deviation of the sensor glucose levels in the perioperative period | 1 day | 
| Standard deviation of sensor glucose levels in the postoperative period | Standard Deviation of the sensor glucose levels in the postoperative period | 1-2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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perioperative glucose management, continuous glucose monitoring, diabetes