What is the recommended glucose level check and management approach for a diabetic patient undergoing radial artery cannulation?

Pre-Radial Artery Cannulation Glucose Check in Diabetic Patients

For diabetic patients undergoing radial artery cannulation, check capillary blood glucose immediately before the procedure and target a range of 6-10 mmol/L (108-180 mg/dL), with acceptable values between 4-12 mmol/L (72-216 mg/dL). 1

Timing and Target Range

• Measure blood glucose immediately before induction of anesthesia when radial artery cannulation will be performed 1
• Target perioperative capillary blood glucose of 6-10 mmol/L (108-180 mg/dL), though acceptable concentrations extend to 4-12 mmol/L (72-216 mg/dL) 1
• The lower limit of 6 mmol/L serves as a safety buffer to prevent hypoglycemia, particularly in patients on insulin, sulfonylureas, or meglitinides 1

Monitoring Frequency During the Procedure

• Monitor glucose at least hourly during any procedure in diabetic patients on glucose-lowering medications 1
• Increase monitoring frequency to every 1-2 hours if results fall outside the target range 1
• Continue hourly monitoring throughout the duration of radial artery cannulation use 1

Optimal Sampling Method

Once the radial arterial line is placed, use arterial blood samples for all subsequent glucose measurements rather than capillary samples. 1

• Arterial blood sampling from the radial line provides more accurate glucose measurements than capillary samples, particularly in hemodynamically unstable patients or those receiving vasopressors 1
• Capillary blood glucose readings can overestimate actual levels, especially during vasoconstriction, and should be avoided once arterial access is established 1, 2
• Arterial blood glucose will be approximately 0.2 mmol/L higher than peripheral venous blood 1

Critical Thresholds Requiring Immediate Action

Hypoglycemia Management

• For glucose <3.3 mmol/L (60 mg/dL): Administer 15-20 grams IV glucose immediately, even without symptoms 1
• For glucose 3.8-5.5 mmol/L (68-99 mg/dL) with symptoms: Administer glucose 1

Hyperglycemia Management

• For glucose >16.5 mmol/L (297 mg/dL) in Type 1 or insulin-treated Type 2 diabetics: Check for ketosis immediately 1
• If ketosis is present, suspect diabetic ketoacidosis and consider ICU transfer 1
• Maintain glucose below 10 mmol/L (180 mg/dL) to reduce infectious and non-infectious postoperative complications 1

Pre-Procedure Preparation

• Schedule diabetic patients early in the morning to minimize fasting time 1, 2
• If the patient uses an insulin pump, it should be maintained until arrival in the surgical unit, then removed with immediate transition to IV insulin 1, 2
• Initiate IV glucose infusion (equivalent to 4 g/hour) if the patient is NPO and on insulin 1

Common Pitfalls to Avoid

• Never rely solely on capillary glucose measurements in patients with vasoconstriction or hemodynamic instability, as these readings are unreliable 1, 2
• Do not allow more than 1 hour between glucose checks in diabetic patients on insulin during procedures 1
• Ensure adequate dead space withdrawal when sampling from the arterial line to avoid contamination from flush solution 1
• Any unexplained malaise should be treated as hypoglycemia until proven otherwise, even if measured glucose appears normal 2

Equipment Access Requirements

• Anaesthetists must have immediate access to capillary blood glucose monitoring equipment before the procedure begins 1
• Ready access to capillary blood ketone monitoring equipment should be available for diabetic patients 1