INS and diabetes mellitus: His scheme still dictates the principles for the perioperative pharmacological management of diabetes: (1) insulin administration is required to prevent lipolysis and subsequent DKA in patients with T1DM; (2) the ideal blood glucose zone for surgical patients on insulin therapy is approximately 5–10 mM; (3) hypoglycaemia especially in the anaesthetised patient with diabetes should be avoided; and (4) hyperglycaemia in surgical patients predisposes to infectious and non-infectious complications and should be avoided.