For patients undergoing neurosurgery, the target for intraoperative blood glucose control is 5.0–10.0 mmol/L and for postoperative blood glucose control is less than 12.0 mmol/L. On the basis of the target range, it is suggested that intraoperative blood glucose level is monitored every 1–2 h and postoperative blood glucose level is monitored every 2–4 h. (2C)

For patients undergoing fine surgery (fine surgery is defined as a minimally invasive or microsurgical procedure requiring high precision, and the types include ophthalmic surgery, facial plastic surgery, among others), the target for preoperative blood glucose control is 5.0–7.2 mmol/L; for patients with a long disease course and those who have difficulty reaching the blood glucose standards, the target for blood glucose control may be increased up to <8.3 mmol/L. The target for intraoperative blood glucose control is 6.7–11.1 mmol/L and for postoperative blood glucose control is less than 12.0 mmol/L. On the basis of the suggested target range, intraoperative blood glucose level is monitored every 1–2 h and postoperative blood glucose level is monitored every 4–6 h. (2C)

For patients undergoing emergency surgery, the target for blood glucose control is the same as that for patients undergoing the corresponding elective surgery; however, intraoperative monitoring should be performed more frequently. (2C)

For patients with gestational diabetes mellitus, the blood glucose control target ranges are as follows: blood glucose >3.3 mmol/L, fasting blood glucose <5.3 mmol/L, postprandial 1‐h blood glucose <7.8 mmol/L and postprandial 2‐h blood glucose <6.7 mmol/L for patients with pre‐pregnancy diabetes, the blood glucose control target can be individualization. (1B) Despite attempts to control their blood glucose levels through a combination of diet and exercise, if the maternal blood glucose levels in pregnant women do not meet the standard, it is suggested that insulin therapy is started. (2C) The blood glucose levels in the course of labour and childbirth should be controlled within 4–7 mmol/L and intraoperative and postoperative blood glucose levels should be controlled within 6.0–12.0 mmol/L. Blood glucose levels should be monitored every 30 min during this time. When the labour is prolonged and the blood glucose level is reduced to <6.0 mmol/L, an intravenous infusion of 5% glucose to increase the blood glucose is suggested. (2C)

For patients in postoperative intensive care or under mechanical ventilation and patients without cardiovascular disease or liver and kidney dysfunction, the target blood glucose level is 7.8–10.0 mmol/L. For patients with cardiovascular and cerebrovascular disease or liver and kidney dysfunction, the target for blood glucose control is 8.0–12.0 mmol/L; however, the upper limit of the target blood glucose level can be extended up to 13.9 mmol/L. The blood glucose levels are monitored every 1–4 h. (2C)

The medical staff should strengthen awareness regarding the prevention of hypoglycaemia, timely identify the hypoglycaemic performance, strengthen the monitoring and management of hypoglycaemia and educate patients and their families on strategies for preventing hypoglycaemia. (1B)

In case of hypoglycaemia, the need for intraoperative infusion of fluids and the dosage of insulin should be determined based on the blood glucose levels. When the blood glucose is between 5.6 and 10.0 mmol/L, no specialised treatment is required, and blood glucose monitoring every 2 h is recommended. Blood glucose below 5.6 mmol/l immediately stop intravenous insulin infusion. During the fasting state, when the blood glucose is less than 4.4 mmol/L, an intravenous injection of 10 g high glucose, and blood glucose monitoring every 15–30 min are recommended. When the blood glucose level is between 4.4 and 5.6 mmol/L, intravenous infusion of 5% glucose at 40 ml/h or 10% glucose at 20 ml/h and blood glucose monitoring every 1 h are recommended . If hypoglycaemia occurs during the nonfasting state, patients are advised to take 10–25 g of glucose orally for rapid absorption of carbohydrates (such as glucose‐based drinks). For patients who are unable to consume oral glucose, an intravenous injection of 20–50 ml of 50% glucose, followed by continuous intravenous infusion of 5% or 10% glucose are used to maintain the blood glucose levels. Blood glucose levels are monitored every 15 min until it reaches ≥5.6 mmol/L. (2C)

During minor and moderate surgeries (i.e., surgery time shorter than 1 h), it is not necessary to perform insulin therapy for patients with diabetes if the blood glucose levels are adequately controlled by the previously administered oral antidiabetic agents. (1B) Glucosidase inhibitors, DPP-IV inhibitors, GLP-1 analogues and PPAR-γ receptor agonists can be administered according to routine. During the fasting period, agents with high risk of causing hypoglycaemia, such as sulfonylurea drugs and non‐sulfonylurea insulin secretagogues should be stopped. (1B) Sodium–glucose cotransporter 2 (SGLT2) inhibitors should be avoided in case of surgical procedures. (2B)

Patients under intraoperative insulin therapy should continue to receive insulin therapy during the postoperative fasting period (24–48 h) until they start eating, following which oral anti‐diabetic agents can be resumed. (2C)

People with diabetes with normal renal function do not need to stop taking metformin before surgery. (2B) However, if the use of an intraoperative iodine contrast agent is necessary, metformin should not be taken 24 h before surgery. For patients with abnormal renal function, metformin should not be taken 48 h before surgery if using an iodine contrast agent and general anaesthesia, and it's administration should be suspended for 48–72 h postsurgery until renal function is normal. (2B) Metformin is not recommended when the glomerular filtration rate (eGFR) is 30–45 ml/(min•1.73 m2 ), and is prohibited when eGFR<30 ml/(min•1.73 m2). (1A)