Given an average glucose pool of 15 to 20 g in the adult and glucose consumption between 120 and 180 mg/min, the standard therapy is 25 g of glucose given intravenously (50 ml of 50 per cent glucose), which usually reawakens a comatose patient in 5 to 10 min. With a plasma half-life of 60 to 80 min, the blood glucose level will fall after this initial bolus depending on the hypoglycemic stimulus and the metabolic state, potentially leading to a relapse into neuroglycopenic symptoms.
If the awakened patient has sufficient protection of the airway (i.e. positive swallowing, gag and cough reflexes), an oral glucose load should be given as soon as possible to maintain blood glucose levels, followed by a high-carbohydrate meal. If an oral load is contraindicated, it is imperative to add an infusion of glucose to initial parenteral therapy (e.g. 200 ml/h of 10 per cent glucose infusion in an adult), with the rate adjusted as necessary to obtain normoglycemia.
Glucose solutions of 10 per cent or stronger are acidic, hyperosmotic, and highly irritant to tissues (the pH of 10 per cent glucose is 5.6, and the osmolarity is 523 mosmol/l). They will thrombose any venous access and should be followed with a flush of 0.9 per cent saline.
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