Transition to subcutaneous insulin
Patients with DKA and HHS should be treated with continuous intravenous insulin until the hyperglycemic crisis is resolved. Criteria for resolution of ketoacidosis include a blood glucose 7.3, and a calculated anion gap ≤12 mEq/l. Resolution of HHS is associated with normal osmolality and regain of normal mental status. When this occurs, subcutaneous insulin therapy can be started. To prevent recurrence of hyperglycemia or ketoacidosis during the transition period to subcutaneous insulin, it is important to allow an overlap of 1–2 h between discontinuation of intravenous insulin and the administration of subcutaneous insulin. If the patient is to remain fasting/nothing by mouth, it is preferable to continue the intravenous insulin infusion and fluid replacement. Patients with known diabetes may be given insulin at the dosage they were receiving before the onset of DKA so long as it was controlling glucose properly. In insulin-naïve patients, a multidose insulin regimen should be started at a dose of 0.5–0.8 units • kg−1 • day−1 (13). Human insulin (NPH and regular) are usually given in two or three doses per day. More recently, basal-bolus regimens with basal (glargine and detemir) and rapid-acting insulin analogs (lispro, aspart, or glulisine) have been proposed as a more physiologic insulin regimen in patients with type 1 diabetes. A prospective randomized trial compared treatment with a basal-bolus regimen, including glargine once daily and glulisine before meals, with a split-mixed regimen of NPH plus regular insulin twice daily following the resolution of DKA. Transition to subcutaneous glargine and glulisine resulted in similar glycemic control compared with NPH and regular insulin; however, treatment with basal bolus was associated with a lower rate of hypoglycemic events (15%) than the rate in those treated with NPH and regular insulin (41%) (55).