Background: Post-operative insulin resistance and hyperglycaemia are associated with an impaired outcome after surgery. Pre-operative oral carbohydrate loading (CHO) reduces post-operative insulin resistance with a reduced risk of hyperglycaemia during post-operative nutrition. Insulin-resistant diabetic patients have not been given CHO because the effects on pre-operative glycaemia and gastric emptying are unknown.
Methods: Twenty-five patients (45–73 years) with type 2 diabetes [glycated haemoglobin (HbA1c) 6.2 ± 0.2%, mean ± SEM] and 10 healthy control subjects (45–72 years) were studied. A carbohydrate-rich drink (400 ml, 12.5%) was given with paracetamol 1.5 g for determination of gastric emptying.
Results: Peak glucose was higher in diabetic patients than in healthy subjects (13.4 ± 0.5 vs. 7.6 ± 0.5 mM; P<0.01) and occurred later after intake (60 vs. 30 min; P<0.01). Glucose concentrations were back to baseline at 180 vs. 120 min in diabetic patients and healthy subjects, respectively (P<0.01). At 120 min, 10.9 ± 0.7% and 13.3 ± 1.2% of paracetamol remained in the stomach in diabetic patients and healthy, subjects respectively. Gastric half-emptying time (T50) occurred at 49.8 ± 2.2 min in diabetics and at 58.6 ± 3.7 min in healthy subjects (P<0.05). Neither peak glucose, glucose at 180 min, gastric T50, nor retention at 120 min differed between insulin (HbA1c 6.8 ± 0.7%)- and non-insulin-treated (HbA1c 5.6 ± 0.4%) patients.
Conclusions: Type 2 diabetic patients showed no signs of delayed gastric emptying, suggesting that a carbohydrate-rich drink may be safely administrated 180 min before anaesthesia without risk of hyperglycaemia or aspiration pre-operatively.